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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.

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.

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.

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.

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.

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.

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.