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  • 1.
    Candefjord, Stefan
    et al.
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Nyberg, Morgan
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ramser, Kerstin
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Lindahl, Olof
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Combining fibre optic Raman spectroscopy and tactile resonance measurement for tissue characterization2010In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 21, no 125801, p. 1-8Article in journal (Refereed)
    Abstract [en]

    Tissue characterization is fundamental for identification of pathological conditions. Raman spectroscopy (RS) and tactile resonance measurement (TRM) are two promising techniques that measure biochemical content and stiffness, respectively. They have potential to complement the golden standard-–histological analysis. By combining RS and TRM, complementary information about tissue content can be obtained and specific drawbacks can be avoided. The aim of this study was to develop a multivariate approach to compare RS and TRM information. The approach was evaluated on measurements at the same points on porcine abdominal tissue. The measurement points were divided into five groups by multivariate analysis of the RS data. A regression analysis was performed and receiver operating characteristic (ROC) curves were used to compare the RS and TRM data. TRM identified one group efficiently (area under ROC curve 0.99). The RS data showed that the proportion of saturated fat was high in this group. The regression analysis showed that stiffness was mainly determined by the amount of fat and its composition. We concluded that RS provided additional, important information for tissue identification that was not provided by TRM alone. The results are promising for development of a method combining RS and TRM for intraoperative tissue characterization.

  • 2.
    Candefjord, Stefan
    et al.
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Nyberg, Morgan
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Ramser, Kerstin
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Lindahl, Olof
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Evaluating the use of a Raman fiberoptic probe in conjunction with a resonance sensor for measuring porcine tissue in vitro2009In: IFMBE Proceedings of the World Congress on Medical Physics and Biomedical Engineering, Heidelberg: Springer , 2009, p. 414-417Conference paper (Refereed)
    Abstract [en]

    Prostate cancer is the most common form of cancer and is the third leading cause of cancer-related death in European men. There is a need for new methods that can accurately localize and diagnose prostate cancer. In this study a new approach is presented: a combination of resonance sensor technology and Raman spectroscopy. Both methods have shown promising results for prostate cancer detection in vitro. The aim of this study was to evaluate the combined information from measurements with a Raman fiberoptic probe and a resonance sensor system. Pork belly tissue was used as a model system. A three-dimensional translation table was equipped with an in-house developed software, allowing measurements to be performed at the same point using two separate instruments. The Raman data was analyzed using principal component analysis and hierarchical clustering analysis. The spectra were divided into 5 distinct groups. The mean stiffness of each group was calculated from the resonance sensor measurements. One of the groups differed significantly (p < 0.05) from the others. A regression analysis, with the stiffness parameter as response variable and the principal component scores of the Raman data as the predictor variables, explained 67% of the total variability. The use of a smaller resonance sensor tip would probably increase the degree of correlation. In conclusion, Raman spectroscopy provides additional discriminatory power to the resonance sensor.

  • 3.
    Candefjord, Stefan
    et al.
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Nyberg, Morgan
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ramser, Kerstin
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Lindahl, Olof
    Dept. of Computer Science and Electrical Engineering, Luleå University of Technology.
    Kombinationsinstrument för detektering av prostatacancer: korrelation mellan resonanssensor och fiberoptisk Ramanprobe2009In: Medicinteknikdagarna 2009, Svensk förening för medicinsk teknik och fysik , 2009, p. 60-Conference paper (Refereed)
  • 4.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Hand-held resonance sensor for tissue stiffness measurements: a theoretical and experimental analysis2010In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 21, no 055801, p. 8pp-Article in journal (Refereed)
    Abstract [en]

    A piezoelectric transducer in a feedback circuit operating in a resonance state is the basis of a resonance sensor. Upon contact with a soft object a change in the resonance frequency reflects the acoustic impedance. Together with force measurement it is possible to obtain the elastic stiffness of the object. The aim of this study was to evaluate the concept of a hand-held resonance sensor for tissue stiffness measurement. A time derivative analysis of the force and the frequency change showed that a stiffness-sensitive parameter was independent of the impression speed. Soft tissue phantoms of gelatin were used in an experimental validation of the theory. A force indentation method was used as a reference method for assessing the gelatin's elastic stiffness. Results from the hand-held measurements showed that the stiffness parameter accurately measured the elastic stiffness of the gelatin (R2 = 0.94, p < 0.05). The stiffness parameter was weakly (on average R2 = 0.15) and non-significantly (p > 0.05, 14 out of 17) dependent on an impression speed parameter. On average, a small amount of the total variance was explained by the impression speed. In conclusion, soft tissue stiffness can be objectively measured with free-hand measurement with a resonance sensor. This study contributes a theoretical analysis and an experimental demonstration of the concept of a hand-held resonance sensor for stiffness measurements.

  • 5.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Handheld resonance sensor instrumentation towards faster diagnosis of prostate cancer: stiffness measurements on a soft tissue phantom2009In: IFMBE Proceedings of the World Congress on Medical Physics and Biomedical Engineering, Heidelberg: Springer , 2009, p. 808-811Conference paper (Refereed)
    Abstract [en]

    Prostate cancer is the most common type of cancer among men. Standard methods for detecting and diagnosing prostate cancer are not sensitive enough. Radical prostatectomy is a procedure where the prostate is removed as a treatment for prostate cancer. Objectively measured prostate stiffness could be a clinical marker for prostate cancer and this could be accomplished with a stiffness sensitive resonance sensor. A future handheld pen-like resonance sensor instrument could be a valuable clinical tool for locating cancer during radical prostatectomy surgery and thus aid in the diagnosis and treatment. The aim of this study was to evaluate the concept of a handheld resonance sensor for stiffness measurements on a soft tissue phantom. For a handheld resonance sensor set-up the impression depth and speed of the sensor tip into the tissue are unknown. A theoretical model was derived to show that a stiffness sensitive parameter can be obtained independent of the impression depth and the impression speed. The theoretical result was verified on a soft tissue phantom made of gelatin with a silicon tumor inclusion. These results were promising for further studies and development of a handheld instrument towards faster diagnosis of prostate cancer.

  • 6.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Handhållen resonanssensor för styvhetsmätning av vävnadsmodeller2009In: Medicinteknikdagarna 2009, Svensk förening för medicinsk teknik och fysik , 2009, p. 62-Conference paper (Refereed)
  • 7.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics.
    Resonance sensor technology for detection of prostate cancer2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Prostate cancer is the most common type of cancer in men in Europe and the USA. Some prostate tumours are regarded as stiffer than the surrounding normal tissue, and therefore it is of interest to be able to reliably measure prostate tissue stiffness. The methods presently used to detect prostate cancer are inexact, and new techniques are needed. In this licentiate thesis resonance sensor technology, with its ability to measure tissue stiffness, was applied to normal and cancerous prostate tissue.

    A piezoelectric transducer element in a feedback system can be set to vibrate at its resonance frequency. When the sensor element contacts an object a change in the resonance frequency is observed, and this feature has been utilized in sensor systems to describe physical properties of different objects. For medical applications it has been used to measure stiffness variations due to various pathophysiological conditions.

    An impression-controlled resonance sensor system was used to quantify stiffness in human prostate tissue in vitro using a combination of frequency change and force measurements. Measurements on prostate tissue showed statistically significant (p < 0.001) and reproducible differences between normal healthy tissue and tumour tissue when using a multivariate parameter analysis. Measured stiffness varied in both the normal tissue and tumour tissue group. One source of variation was assumed to be related to differences in tissue composition. Other sources of error could be uneven surfaces, different levels of dehydration of the prostates, and actual differences between patients.

    The prostate specimens were also subjected to morphometric measurements, and the sensor parameter was compared with the morphology of the tissue with linear regression. In the probe impression interval 0.5–1.7 mm, the maximum coefficient of determination was R2 ≥ 0.60 (p < 0.05, n = 75). An increase in the proportion of prostate stones (corpora amylacea), stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Cancer and stroma had the greatest effect on the measured stiffness. The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed.

    It is concluded that prostate cancer increases the measured stiffness as compared with healthy glandular tissue, but areas with predominantly stroma or many stones could be more difficult to differentiate from cancer. Furthermore, the results of this study indicated that the resonance sensor could be used to detect stiffness variations in human prostate tissue in vitro, and especially due to prostate cancer. This is promising for the development of a future diagnostic tool for prostate cancer.

  • 8.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Tactile sensing of prostate cancer: a resonance sensor method evaluated using human prostate tissue in vitro2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Prostate cancer is the most frequent type of cancer in men in Europe and the USA. The methods presently used to detect and diagnose prostate cancer are inexact, and new techniques are needed. Prostate tumours can be regarded as harder than the surrounding normal healthy glandular tissue, and therefore it is of interest to be able to reliably measure prostate tissue stiffness. In this dissertation the approach was to evaluate tactile resonance sensor technology and its ability to measure mechanical properties and to detect cancer in human prostate tissue.

    The tactile resonance sensor is based on a piezoelectric transducer element vibrating at its resonance frequency through a feedback circuit. A change in the resonance frequency is observed when the sensor contacts an object. This feature has been utilized to measure tissue stiffness variations due to various pathophysiological conditions.

    An impression-controlled tactile resonance sensor system was first used to quantify stiffness and evaluate performance on silicone. Then the sensor system was used on fresh human prostate tissue in vitro to measure stiffness using a combination of frequency change and force measurements. Significant differences in measured stiffness between malignant and healthy normal tissue were found, but there were large variations within the groups.

    Some of the variability was explained by prostate tissue histology using a tissue stiffness model. The tissue content was quantified at four depths in the tissue specimens with a microscope-image-based morphometrical method involving a circular grid. Numerical weights were assigned to the tissue data from the four depths, and the weighted tissue proportions were related to the measured stiffness through a linear model which was solved with a least-squares method. An increase in the proportion of prostate stones, stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Stroma and cancer had the greatest effect and accounted for 90 % of the measured stiffness (45% and 45%, respectively).

    The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed. A sensing depth was extrapolated from the numerical weights for the measurements performed at different impression depths. Horizontal surface tissue variations were studied by altering the circular grid size relative to the contact area between the sensor tip and the tissue. The results indicated that the sensing area was greater than the contact area. The sensor registered spatial tissue variations.

    Tissue density-related variations, as measured by the frequency change, were weakly significant or non-significant. The measured force registered elastic-related tissue variations, to which stroma and cancer were the most important variables.

    A theoretical material-dependent linear relation was found between frequency change and force from theoretical models of frequency change and force. Tactile resonance sensor measurements on prostate tissue verified this at small impression depths. From this model, a physical interpretation was given to the parameters used to describe stiffness.

    These results indicate that tactile resonance sensor technology is promising for assessing soft tissue mechanical properties and especially for prostate tissue stiffness measurement with the goal of detecting prostate cancer. However, further studies and development of the sensor design must be performed to determine the full potential of the method and its diagnostic power. Preferably, measurements of tissue mechanical properties should be used in combination with other methods, such as optical methods, to increase the diagnostic power.

  • 9.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Medical Biosciences. Umeå University, Faculty of Medicine, Medical Biosciences, Pathology.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences. Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Urology and Andrology.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Detection of prostate cancer with a resonance sensor2005In: IFMBE Proccedings: NBC'05 Umeå 13th Nordic Baltic Conferenceon Biomedical Engineering and Medical Physics, Umeå, 2005, p. 130-131Conference paper (Refereed)
  • 10.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Lindahl, Olof
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Indentation loading response of a resonance sensor: discriminating prostate cancer and normal tissue2013In: Journal of Medical Engineering & Technology, ISSN 0309-1902, E-ISSN 1464-522X, Vol. 37, no 7, p. 416-423Article in journal (Refereed)
    Abstract [en]

    Prostate cancer is the most common type of cancer among men worldwide. Mechanical properties of prostate tissue are promising for distinguishing prostate cancer from healthy prostate tissue. The aim was to investigate the indentation loading response of a resonance sensor for discriminating prostate cancer tissue from normal tissue. Indentation measurements were done on prostate tissue specimens ex vivo from 10 patients from radical prostatectomy. The measurement areas were analysed using standard histological methods. The stiffness parameter was linearly dependent on the loading force (average R2 = 0.90) and an increased loading force caused a greater stiffness contrast of prostate cancer vs normal tissue. The accuracy of the stiffness contrast was assessed by the ROC curve with the area under the curve being 0.941 for a loading force of 12.8 mN. The results are promising for the development of a resonance sensor instrument for detecting prostate cancer.

  • 11.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Eklund, Anders
    Medicinsk teknik och informatik, Biomedical Engineering and Informatics, Umeå University Hospital.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    A resonance sensor technique to detect cancer in prostate - Model experiments in silicone2002In: IFMBE Proceedings: The 12th Nordic Baltic Conference on Biomedical Engineering and Medical Physics, Reykjavik, 2002, p. 33-34Conference paper (Refereed)
  • 12.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof
    Dept of Computer Science and Electrical Engineering, Luleå University of Technology.
    Instrument towards faster diagnosis and treatment of prostate cancer: Resonance sensor stiffness measurements on human prostate tissue in vitro2009In: IFMBE Proceedings of the World Congress on Medical Physics and Biomedical Engineering, Heidelberg: Springer , 2009, p. 145-148Conference paper (Refereed)
    Abstract [en]

    Prostate cancer is the most common cancer among men and the methods used to detect and diagnose prostate cancer are not sufficiently accurate. Radical prostatectomy is a surgical treatment of prostate cancer where the whole prostate is removed from the patient. Prostate tissue stiffness can be measured with a stiffness sensitive resonance sensor. The aim of this study was to measure the stiffness on the anterior and posterior side of fresh human prostate tissue in vitro and compare these two groups with each other and relate the findings with the prostate tissue histology.  In a prostate tissue slice with mostly normal healthy tissue, the anterior side was significantly harder (p-value < 0.05) as expected. In a prostate tissue slice with areas of cancer tumors, no difference was found between the anterior and posterior sides. However, large stiffness variations were found within groups with measurements points on cancer tissue (coefficient of variation, CV = 42 and 85%), as opposed to groups without cancer tissue (CV = 27 and 28%).  The large stiffness variations could be used as a sign for the presence of cancer. The results are promising for the development of an instrument and method for faster diagnosis on radical prostatectomy samples.

  • 13.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof
    Dept. of Computer Science and Electrical Engineering (Systemteknik), Luleå University of Technology.
    Stiffness of a small tissue phantom measured by a tactile resonance sensor2010In: IFMBE Proceedings of XII Mediterranean Conference on Medical and Biological Engineering and Computing, Heidelberg: Springer , 2010, p. 395-398Conference paper (Refereed)
  • 14.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Medical Biosciences.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Resonance sensor for prostate tissue stiffness measurements – detecting prostate cancer2006In: World Congress on Biomedical Engineering and Medical Physics, August 27 - September 1, 2006, Seoul, Korea, IFMBE , 2006Conference paper (Refereed)
  • 15.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Lindahl, Olof A
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Explanatory models for a tactile resonance sensor system-elastic and density-related variations of prostate tissue in vitro2008In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 29, no 7, p. 729-745Article in journal (Refereed)
    Abstract [en]

    Tactile sensors based on piezoelectric resonance have been adopted for medical applications. The sensor consists of an oscillating piezoelectric sensor–circuit system, and a change in resonance frequency is observed when the sensor tip contacts a measured object such as tissue. The frequency change at a constant applied force or mass load is used as a stiffness-sensitive parameter in many applications. Differential relations between force and frequency have also been used for monitoring intraocular pressure and stiffness variations in prostate tissue in vitro. The aim of this study was to relate the frequency change (Δf), measured force (F) and the material properties, density and elasticity to an explanatory model for the resonance sensor measurement principle and thereby to give explanatory models for the stiffness parameters used previously. Simulations of theoretical equations were performed to investigate the relation between frequency change and contact impedance. Measurements with a resonance sensor system on prostate tissue in vitro were used for experimental validation of the theory. Tissue content was quantified with a microscopic-based morphometrical method. Simulation results showed that the frequency change was dependent upon density (ρ) and contact area (S) according to Δf ∝ ρS3/2. The experiments followed the simulated theory at small impression depths. The measured contact force followed a theoretical model with the dependence of the elastic modulus (E) and contact area, FES3/2. Measured density variations related to histological variations were statistically weak or non-significant. Elastic variations were statistically significant with contributions from stroma and cancer relative to normal glandular tissue. The theoretical models of frequency change and force were related through the contact area, and a material-dependent explanatory model was found as Δf ∝ ρE−1F. It explains the measurement principle and the previously established stiffness parameters from the material properties point of view.

  • 16.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Medical Biosciences.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Lindahl, Olof A
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Prostate tissue stiffness as measured with a resonance sensor system: a study on silicone and human prostate tissue in vitro.2006In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 44, no 7, p. 593-603Article in journal (Refereed)
    Abstract [en]

    Prostate cancer is the most common form of cancer in men in Europe and in the USA. Some prostate tumours are stiffer than the surrounding normal tissue, and it could therefore be of interest to measure prostate tissue stiffness. Resonance sensor technology based on piezoelectric resonance detects variations in tissue stiffness due to a change in the resonance frequency. An impression-controlled resonance sensor system was used to detect stiffness in silicone rubber and in human prostate tissue in vitro using two parameters, both combinations of frequency change and force. Variations in silicone rubber stiffness due to the mixing ratio of the two components could be detected (p<0.05) using both parameters. Measurements on prostate tissue showed that there existed a statistically significant (MANOVA test, p<0.001) reproducible difference between tumour tissue (n=13) and normal healthy tissue (n=98) when studying a multivariate parameter set. Both the tumour tissue and normal tissue groups had variations within them, which were assumed to be related to differences in tissue composition. Other sources of error could be uneven surfaces and different levels of dehydration for the prostates. Our results indicated that the resonance sensor could be used to detect stiffness variations in silicone and in human prostate tissue in vitro. This is promising for the development of a future diagnostic tool for prostate cancer.

  • 17.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Medical Biosciences.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Lindahl, Olof A
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Resonance sensor measurements of stiffness variations in prostate tissue in vitro: a weighted tissue proportion model2006In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 27, no 12, p. 1373-86Article in journal (Refereed)
    Abstract [en]

    Prostate cancer is the most common type of cancer in men in Europe and the US. The methods to detect prostate cancer are still precarious and new techniques are needed. A piezoelectric transducer element in a feedback system is set to vibrate with its resonance frequency. When the sensor element contacts an object a change in the resonance frequency is observed, and this feature has been utilized in sensor systems to describe physical properties of different objects. For medical applications it has been used to measure stiffness variations due to various patho-physiological conditions. In this study the sensor's ability to measure the stiffness of prostate tissue, from two excised prostatectomy specimens in vitro, was analysed. The specimens were also subjected to morphometric measurements, and the sensor parameter was compared with the morphology of the tissue with linear regression. In the probe impression interval 0.5-1.7 mm, the maximum R(2) > or = 0.60 (p < 0.05, n = 75). An increase in the proportion of prostate stones (corpora amylacea), stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Cancer and stroma had the greatest effect on the measured stiffness. The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed. Tissue sections deeper in the tissue were assigned a lower mathematical weighting than sections closer to the sensor probe. It is concluded that cancer increases the measured stiffness as compared with healthy glandular tissue, but areas with predominantly stroma or many stones could be more difficult to differ from cancer.

  • 18.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Resonanssensorteknik för detektering av prostatacancer2010In: Medicinteknikdagarna 2010 / [ed] Ronnie Lundström, Umeå: Svensk förening för medicinsk teknik och fysik , 2010, p. 193-193Conference paper (Refereed)
  • 19.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Medical Biosciences.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences.
    Lindahl, Olof A
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Spatial variations in prostate tissue histology as measured by a tactile resonance sensor2007In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 28, no 10, p. 1267-81Article in journal (Refereed)
    Abstract [en]

    In recent years, tactile sensors based on piezoelectric resonance sensor technology have been used for medical diagnosis where the sensor's stiffness-measuring properties can reflect tissue pathology. The change in the frequency of the resonating system and the change in force when contact is made with tissue are used as a stiffness parameter. Earlier stiffness measurements of prostate tissue in vitro demonstrate variations related to tissue composition. In this study, measured stiffness from two human prostate specimens was compared to histological composition of prostate tissue below and around the measurement points. Tissue stiffness was measured with the resonance sensor system. Tissue composition was measured at four different depths in the tissue specimen using a microscopic-image-based morphometrical method. With this method, the proportion of tissue types was determined at the points of intersections in a circular grid on the images representing each measurement point. Numerical values were used for weighting the tissue proportions at different depths in the tissue specimen. For an impression depth of 1.0 mm, the sensing depth in this study was estimated to be 3.5-5.5 mm. Stiffness variations due to horizontal tissue variations were investigated by studying the dependence of the size of the circular grid area relative to the contact area of the sensor tip. The sensing area (grid radius) was estimated to be larger than the contact area (contact radius) between the sensor tip and the tissue. Thus, the sensor tip registers spatial variations in prostate tissue histology, both directly below and lateral to the tip itself. These findings indicate that tumours around the sensor tip could be detected, which in turn supports the idea of a future resonance-sensor-based clinical device for detecting tumours and for guiding biopsies.

  • 20.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Eklund, Anders
    Medicinsk teknik och informatik, Biomedical Engineering and Informatics, Umeå University Hospital.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics.
    Force and frequency shift from a resonance sensor for detection of prostate cancer2003In: IFMBE Proceedings: World Congress on Medical Physics and Biomedical Engineering, Sydney, 2003Conference paper (Refereed)
  • 21.
    Jalkanen, Ville
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof
    Dept. of Computer Science and Electrical Engineering (Systemteknik), Luleå University of Technology.
    Hand-held resonance sensor instrument for soft tissue stiffness measurements:  a first study on biological tissue in vitro2010In: IFMBE Proceedings of XII Mediterranean Conference on Medical and Biological Engineering and Computing, Heidelberg: Springer , 2010, p. 463-466Conference paper (Refereed)
  • 22.
    Lindahl, Olof A.
    et al.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet.
    Nyberg, Morgan
    Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet.
    Jalkanen, Ville
    Department of engineering sciences and mathematics, Luleå University of Technology, Luleå, Sweden.
    Ramser, Kerstin
    Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet.
    Prostate cancer detection using a combination of Raman spectroscopy and stiffness sensing2015In: 1st Global Conference on Biomedical Engineering and 9th Asian-Pacific Conference on Medical and Biological Engineering: October 9-12, 2014, Tainan, Taiwan / [ed] Fong-Chin Su, Shyh-Hau Wang, Ming-Long Yeh, Springer International Publishing , 2015, p. 267-270Conference paper (Refereed)
    Abstract [en]

    Prostate cancer (PCa) is the most common cancer form for men in Europe. A sensor system combining Raman spectroscopy and stiffness sensing with a resonance sensor has recently been developed by us for prostate cancer detection. In this study the sensor system has been used for measurements on two slices of fresh human prostate tissue. The stiffness sensor could detect locations slices with significantly different stiffness contrasts (p < 0.05). Raman spectroscopic measurements could be performed with the dual-modality probe for tissue classification. The findings are important for the continued development of a combination probe for prostate cancer detection.

  • 23.
    Nyberg, Morgan
    et al.
    Luleå University of Technology.
    Candefjord, Stefan
    Luleå University of Technology and Chalmers University of Technology.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ramser, Kerstin
    Luleå University of Technology.
    Lindahl, Olof A
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    A combined tactile and Raman probe for tissue characterization - design considerations2012In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 23, no 6, p. 065901-Article in journal (Refereed)
    Abstract [en]

    Histopathology is the golden standard for cancer diagnosis and involves the characterization of tissue components. It is labour intensive and time consuming. We have earlier proposed a combined fibre-optic near-infrared Raman spectroscopy (NIR-RS) and tactile resonance method (TRM) probe for detecting positive surgical margins as a complement to interoperative histopathology. The aims of this study were to investigate the effects of attaching an RS probe inside a cylindrical TRM sensor and to investigate how laser-induced heating of the fibre-optic NIR-RS affected the temperature of the RS probe tip and an encasing TRM sensor. In addition, the possibility to perform fibre-optic NIR-RS in a well-lit environment was investigated. A small amount of rubber latex was preferable for attaching the thin RS probe inside the TRM sensor. The temperature rise of the TRM sensor due to a fibre-optic NIR-RS at 270 mW during 20 s was less than 2 °C. Fibre-optic NIR-RS was feasible in a dimmed bright environment using a small light shield and automatic subtraction of a pre-recorded contaminant spectrum. The results are promising for a combined probe for tissue characterization.

  • 24.
    Nyberg, Morgan
    et al.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Dept. of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ramser, Kerstin
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Dept. of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Lindahl, Olof A.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Dept. of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Dual-modality probe intended for prostate cancer detection combining Raman spectroscopy and tactile resonance technology—discrimination of normal human prostate tissues ex vivo2015In: Journal of Medical Engineering & Technology, ISSN 0309-1902, E-ISSN 1464-522X, Vol. 39, no 3, p. 198-207Article in journal (Refereed)
    Abstract [en]

    Prostate cancer is the most common cancer for men in the western world. For the first time, a dual-modality probe, combining Raman spectroscopy and tactile resonance technology, has been used for assessment of fresh human prostate tissue. The study investigates the potential of the dual-modality probe by testing its ability to differentiate prostate tissue types ex vivo. Measurements on four prostates show that the tactile resonance modality was able to discriminate soft epithelial tissue and stiff stroma (p<0.05). The Raman spectra exhibited a strong fluorescent background at the current experimental settings. However, stroma could be discerned from epithelia by integrating the value of the spectral background. Combining both parameters by a stepwise analysis resulted in 100% sensitivity and 91% specificity. Although no cancer tissue was analysed, the results are promising for further development of the instrument and method for discriminating prostate tissues and cancer.

  • 25.
    Nyberg, Morgan
    et al.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Institutionen för teknikvetenskap och matematik, Luleå tekniksa universitet.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ramser, Kerstin
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet.
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Institutionen för teknikvetenskap och matematik, Luleå tekniksa universitet.
    First study on freshly operated prostate tissue using a combination of Raman spectroscopy and tactile resonance sensor technology2014In: Medicinteknikdagarna 2014: Göteborg, 14-16 oktober, 2014, 2014, p. 26-26Conference paper (Refereed)
  • 26.
    Nyberg, Morgan
    et al.
    Institutionen för systemteknik, Luleå tekniska universitet, Department of Computer Science and Electrical Engineering, Luleå University of Technology.
    Ramser, Kerstin
    Institutionen för systemteknik, Luleå tekniska universitet, Department of Computer Science and Electrical Engineering, Luleå University of Technology.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Institutionen för systemteknik, Luleå tekniska universitet, Department of Computer Science and Electrical Engineering, Luleå University of Technology.
    Kombinationsprob för prostatacancerdiagnostik - Ramanspektroskopi i dagsljus2010In: Medicinteknikdagarna 2010 / [ed] Ronnie Lundström, Umeå: Svensk förening för medicinsk teknik och fysik , 2010, p. 166-166Conference paper (Refereed)
  • 27.
    Nyberg, Morgan
    et al.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Computer Science, Electrical and Space Engineering, Luleå University of Technology.
    Ville, Jalkanen
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Ramser, Kerstin
    Computer Science, Electrical and Space Engineering, Luleå University of Technology.
    Lindahl, Olof A
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    First clinical study of prostate cancer detection with a dual sensor combining tactile resonance technique with fiber optical Raman spectroscopy2013In: 9th Workshop on FT-IR Spectroscopy in Microbiological and Medical Diagnostics, 2013Conference paper (Refereed)
  • 28.
    Pålsson, Johan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Holmgren, Ulf
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bränberg, Agneta
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    PBL för att stötta professionsfärdigheter2013Conference paper (Refereed)
  • 29.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Börje, Ljungberg
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Anders, Bergh
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Lindahl, Olof
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Prostate cancer detection with a tactile resonance sensor: measurement considerations and clinical setup2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 11, article id 2453Article in journal (Refereed)
    Abstract [en]

    Tumors in the human prostate are usually stiffer compared to surrounding non-malignant glandular tissue, and tactile resonance sensors measuring stiffness can be used to detect prostate cancer. To explore this further, we used a tactile resonance sensor system combined with a rotatable sample holder where whole surgically removed prostates could be attached to detect tumors on, and beneath, the surface ex vivo. Model studies on tissue phantoms made of silicone and porcine tissue were performed. Finally, two resected human prostate glands were studied. Embedded stiff silicone inclusions placed 4 mm under the surface could be detected in both the silicone and biological tissue models, with a sensor indentation of 0.6 mm. Areas with different amounts of prostate cancer (PCa) could be distinguished from normal tissue (p < 0.05), when the tumor was located in the anterior part, whereas small tumors located in the dorsal aspect were undetected. The study indicates that PCa may be detected in a whole resected prostate with an uneven surface and through its capsule. This is promising for the development of a clinically useful instrument to detect prostate cancer during surgery.

  • 30.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ljungberg, Börje
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Urology and Andrology.
    Bergh, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    The first study on whole human prostate ex vivo using a tactile resonance sensor for cancer detectionArticle in journal (Other academic)
    Abstract [en]

    Prostate cancer (PCa) is the most common form of cancer among males in Europe and the USA. A prostatectomy i.e. the removal of the prostate is the most common form of curative treatment. Prostate cancer can be suspected by a blood test for a prostate specific antigen (PSA) and a digital rectal examination (DRE) where a physician palpates the prostate through the rectum and where stiff nodules on the prostate is an indication for PCa. The final diagnosis of PCa is made by microscopic evaluation of ultrasound-guided biopsies taken from suspicious parts of the gland. After a prostatectomy the entire prostate is histopathologically analysed. One area of interest is the superficial part of the prostate gland as tumour growth on the surface suggests that the cancer has spread to other parts of the body.

     

    Tactile resonance sensors can be used to detect areas of different stiffness in soft tissue through a stiffness parameter. It is suggested that tactile resonance sensors can be used to detect prostate cancer since tumours in the human prostate usually is stiffer compared to surrounding healthy glandular tissue.

     

    The aim of the study was to detect tumours on, and beneath the surface, of whole human prostate glands ex vivo using a tactile resonance sensor system (TRSS). Model studies on spherical shaped tissue phantoms made of silicone and porcine tissue were performed to evaluate the ability of the TRSS to detect stiffer volumes at a distance beneath the surface. Finally two resected human prostate glands ex vivo from patients undergoing surgery for prostate cancer were studied.

     

    From the results it was concluded that the clamping force from the rotatable sample holder did not affect the magnitude of the stiffness parameter for the silicone samples. For the porcine muscle samples, the stiffness parameter showed to be affected by clamping forces larger than about 800 mN. The embedded stiff silicone nodules placed about 4 mm under the surface could be detected in both the silicone and biological tissue models with a sensor indentation distance of 0.6 mm. The measurements on resected whole human prostates showed that areas with elevated stiffness parameter values correlated (p < 0.05) with areas where cancer tumours were detected using histolopathological evaluation of the prostate. The tumours were significantly stiffer than the healthy tissue in the dorsal region. This is promising for the development of a clinically useful instrument to detect superficial prostate cancer.

  • 31.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    A flexible resonance sensor instrument for measurements of soft tissue: evaluation on silicone modelsManuscript (preprint) (Other academic)
  • 32.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Ansättningsvinkelns betydelse vid mätning med piezoelektriska resonanssensorer på vävnadsmodeller av silikon2011In: Medicinteknikdagarna 2011, 2011, p. 110-110Conference paper (Other academic)
  • 33.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Stiffness measurements on spherical surfaces of prostate models using a resonance sensor2013In: World Congress on Medical Physics and Biomedical Engineering May 26-31, 2012, Beijing, China / [ed] Mian Long, Springer Berlin/Heidelberg, 2013, p. 1401-1404Conference paper (Refereed)
    Abstract [en]

    Prostate cancer is one of the most common formsof cancer among men in Europe and the United States.Piezoelectric resonance sensors can be used in medicalresearch for measurements of stiffness of human tissue.Cancer tissue is usually stiffer and has different biomechanicalproperties compared to healthy tissue. The frequency shiftobserved when a piezoelectric resonance sensor comes intocontact with a tissue surface has been suggested to correlatewith the stiffness variations, e.g. due to cancer. An instrumenthas been developed, with which it is possible to scan flat andspherical objects and where the sensor can be tilted fordifferent contact angles. Measurements performed in thisstudy on spherical tissue models made of silicone, showed theimportance of keeping the contact angle perpendicular to thesurface of the sphere. The results are promising for futurestudies on prostate tissue to complete the evaluation of theinstrument.

  • 34.
    Åstrand, Anders
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Contact angle and indentation velocity dependency for a resonance sensor: Evaluation on soft tissue silicone models2013In: Journal of Medical Engineering & Technology, ISSN 0309-1902, E-ISSN 1464-522X, Vol. 37, no 3, p. 185-196Article in journal (Refereed)
    Abstract [en]

    Human tissue stiffness can vary due to different tissue conditions such as cancer tumours. Earlier studies show that stiffness may be detected with a resonance sensor that measures frequency shift and contact force at application. Through the frequency shift and the contact force, a tissue stiffness parameter can be derived. This study evaluated how the probe application angle and indentation velocity affected the results and determined the maximum parameter errors. The evaluation was made on flat silicone discs with specified hardness. The frequency shift, the force and the stiffness parameter all varied with contact angle and indentation velocity. A contact angle of ≤10° was acceptable for reliable measurements. A low indentation velocity was recommended. The maximum errors for the system were <1.1% of the measured values. It was concluded that contact angle and indentation velocity have to be considered in the clinical setting. The angular dependency is especially important in clinical use for studying stiffness of human soft tissue, e.g. in prostate cancer diagnosis.

  • 35.
    Åstrand, Anders P.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet.
    Initial Measurements on Whole Human Prostate ex vivo with a Tactile Resonance Sensor in Order to Detect Prostate Cancer2015In: 16th Nordic-Baltic Conference on Biomedical Engineering: 16. NBC & 10. MTD 2014 joint conferences. October 14-16, 2014, Gothenburg, Sweden / [ed] Henrik Mindedal, Mikael Persson, Springer International Publishing , 2015, p. 120-123Conference paper (Refereed)
    Abstract [en]

    Prostate cancer (PCa) is the most common form of cancer among the male population in Europe and the USA. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, followed by a digital rectal examination (DRE). The objective with the DRE is to investigate the presence of stiff nodules on the prostate. Stiff nodules can indicate PCa and biopsies are taken from the suspicious parts of the prostate using guidance of a transrectal ultrasound. Microscopic evaluation of the biopsies is used for final diagnosis. Superficial tumor growth on, and beneath the surface of the gland is of special interest as it suggests that the cancer has spread to other parts of the body.

    Tactile resonance sensors can be used to distinguish between areas of different stiffness in soft tissue. The aim was to detect tumors on, and beneath the surface of a whole human prostate ex vivo.

    A tactile resonance sensor system (TRSS) based on a piezoelectric resonance sensor and a force sensor has been used to detect areas with increased stiffness in soft tissue. The TRSS has a rotatable sample holder for measurements on spherical shaped samples. Stiffness measurements were made on samples of porcine muscle tissue with embedded stiff silicone nodules placed under the surface. Further measurements were made on a resected whole human prostate with PCa.

    The results showed that through the measured stiffness parameter, the stiff silicone nodules placed down to 4 mm under the surface could be detected. The measurements on the prostate showed that elevated values of the stiffness parameter correlated (p < 0.05) with areas in the anterior of the prostate where cancer tumors were detected by histopathological evaluation. The tumors were significantly stiffer than the healthy tissue in the dorsal region.

    The results are promising for further development of a clinically useful instrument to detect superficial PCa.

  • 36.
    Åstrand, Anders P.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Luleå Univ Technol, Dept Comp Sci, Elect & Space Engn, Luleå, Sweden.
    A flexible sensor system using resonance technology for soft tissue stiffness measurements: evaluation on silicone2011In: 15TH NORDIC-BALTIC CONFERENCE ON BIOMEDICAL ENGINEERING AND MEDICAL PHYSICS (NBC 2011) / [ed] K. Dremstrup, S. Rees, M.Ø. Jensen, Aalborg: Springer , 2011, p. 21-24Conference paper (Refereed)
    Abstract [en]

    One of the most common forms of cancer amongmen in Europe and the United States is prostate cancer. Thecancerous tissue is less soft, and has different biomechanicalproperties compared to healthy tissue. It has been shown thattactile sensors can be used to distinguish this difference. If apiezoelectric sensor is set to oscillate at its resonance frequencythrough a feed back circuit, a frequency shift is observed whenthe sensor comes in contact with a surface. This shift can becorrelated to the stiffness of the tissue. A flexible instrumenthas been developed, with which it is possible to scan both flatand spherical bodies and where the sensor can be tilted to havedifferent contact angles. Measurements performed in thisstudy on flat silicone discs of different stiffness showed arelationship between both the frequency shift and theimpression depth for the different silicone discs, when aconstant force was applied. The results are promising forfuture studies on silicone with different geometries and finallyon prostate tissue to complete the evaluation.

  • 37.
    Åstrand, Anders P
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Andersson, Britt M
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindahl, Olof A
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Initial Measurements on Whole Human Prostate ex vivo with a Tactile Resonance Sensor in Order to Detect Prostate CancerManuscript (preprint) (Other academic)
  • 38.
    Åstrand, Anders P.
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Jalkanen, Ville
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Lindahl, Olof A.
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Andersson, Britt M.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Mätutrustning för kontrollerad mätning och karaktärisering av vävnad2010In: Medicinteknikdagarna 2010 / [ed] Ronnie Lundström, Umeå: Svensk förening för medicinsk teknik och fysik , 2010, p. 167-167Conference paper (Refereed)
1 - 38 of 38
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