umu.sePublications
Change search
Link to record
Permanent link

Direct link
BETA
Nyholm, Tufve
Alternative names
Publications (10 of 69) Show all publications
Engvall, G., Lindh, V., Mullaney, T., Nyholm, T., Lindh, J. & Ångström-Brännström, C. (2018). Children's experiences and responses towards an intervention for psychological preparation for radiotherapy. Radiation Oncology, 13, Article ID 9.
Open this publication in new window or tab >>Children's experiences and responses towards an intervention for psychological preparation for radiotherapy
Show others...
2018 (English)In: Radiation Oncology, ISSN 1748-717X, E-ISSN 1748-717X, Vol. 13, article id 9Article in journal (Refereed) Published
Abstract [en]

Background: Children can experience distress when undergoing radiotherapy as a reaction to being scared of and unfamiliar with the procedure. The aim was to evaluate children's experiences and responses towards an intervention for psychological preparation for radiotherapy.

Methods: A case control design with qualitative content analysis of semi-structured interviews and statistical analysis of anxiety ratings were used for evaluating a strategy for psychological preparation and distraction. Fifty-seven children aged 2 to 18 years and their parents participated - 30 children in the baseline group and 27 in the intervention group. Child interviews were performed and the child and their parents rated the child's anxiety.

Results: The intervention was most appropriate for the younger children, who enjoyed the digital story, the stuffed animal and training with their parents. There were some technical problems and the digital story was not detailed enough to fit exactly with various cancer diagnoses. Children described suggestions for improvement of the intervention. The ratings of the child's anxiety during radiation treatment showed no differences between the baseline group and the intervention group.

Conclusions: The children of all the age groups experienced their interventions as positive. The strength of the intervention was that it encouraged interaction within the family and provided an opportunity for siblings and peers to take part in what the child was going through. Future research on children's experiences to interventions should be encouraged. The intervention and the technical solutions could improve by further development.

Trial registration: The study design was structured as an un-matched case-control study, baseline group vs. intervention group. Trial registration: ClinicalTrials.gov NCT02993978 , Protocol Record 2012-113-31 M. Retrospectively registered - 21 November 2016.

Place, publisher, year, edition, pages
BioMed Central, 2018
Keywords
childhood cancer, children’s experiences, distraction, psychological preparation, radiotherapy
National Category
Nursing
Identifiers
urn:nbn:se:umu:diva-144573 (URN)10.1186/s13014-017-0942-5 (DOI)000423350200001 ()29357940 (PubMedID)
Available from: 2018-02-06 Created: 2018-02-06 Last updated: 2018-06-09Bibliographically approved
Garpebring, A., Brynolfsson, P., Kuess, P., Georg, D., Helbich, T. H., Nyholm, T. & Löfstedt, T. (2018). Density Estimation of Grey-Level Co-Occurrence Matrices for Image Texture Analysis. Physics in Medicine and Biology, 63(19), 9-15, Article ID 195017.
Open this publication in new window or tab >>Density Estimation of Grey-Level Co-Occurrence Matrices for Image Texture Analysis
Show others...
2018 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 63, no 19, p. 9-15, article id 195017Article in journal (Refereed) Published
Abstract [en]

The Haralick texture features are common in the image analysis literature, partly because of their simplicity and because their values can be interpreted. It was recently observed that the Haralick texture features are very sensitive to the size of the GLCM that was used to compute them, which led to a new formulation that is invariant to the GLCM size. However, these new features still depend on the sample size used to compute the GLCM, i.e. the size of the input image region-of-interest (ROI).

The purpose of this work was to investigate the performance of density estimation methods for approximating the GLCM and subsequently the corresponding invariant features.

Three density estimation methods were evaluated, namely a piece-wise constant distribution, the Parzen-windows method, and the Gaussian mixture model. The methods were evaluated on 29 different image textures and 20 invariant Haralick texture features as well as a wide range of different ROI sizes.

The results indicate that there are two types of features: those that have a clear minimum error for a particular GLCM size for each ROI size, and those whose error decreases monotonically with increased GLCM size. For the first type of features, the Gaussian mixture model gave the smallest errors, and in particular for small ROI sizes (less than about 20×20).

In conclusion, the Gaussian mixture model is the preferred method for the first type of features (in particular for small ROIs). For the second type of features, simply using a large GLCM size is preferred.

Place, publisher, year, edition, pages
Institute of Physics and Engineering in Medicine, 2018
Keywords
Haralick features, invariant features, GLCM, density estimation, texture analysis, image analysis
National Category
Computer Vision and Robotics (Autonomous Systems) Other Mathematics
Identifiers
urn:nbn:se:umu:diva-152488 (URN)10.1088/1361-6560/aad8ec (DOI)000446205200005 ()30088815 (PubMedID)
Funder
Västerbotten County CouncilVINNOVA
Available from: 2018-10-08 Created: 2018-10-08 Last updated: 2018-10-31Bibliographically approved
Gronlund, E., Johansson, S., Nyholm, T., Thellenberg, C. & Ahnesjo, A. (2018). Dose painting of prostate cancer based on Gleason score correlations with apparent diffusion coefficients. Acta Oncologica, 57(5), 574-581
Open this publication in new window or tab >>Dose painting of prostate cancer based on Gleason score correlations with apparent diffusion coefficients
Show others...
2018 (English)In: Acta Oncologica, ISSN 0284-186X, E-ISSN 1651-226X, Vol. 57, no 5, p. 574-581Article in journal (Refereed) Published
Abstract [en]

Background: Gleason scores for prostate cancer correlates with an increased recurrence risk after radiotherapy (RT). Furthermore, higher Gleason scores correlates with decreasing apparent diffusion coefficient (ADC) data from diffusion weighted MRI (DWI-MRI). Based on these observations, we present a formalism for dose painting prescriptions of prostate volumes based on ADC images mapped to Gleason score driven dose-responses.

Methods: The Gleason score driven dose-responses were derived from a learning data set consisting of pre-RT biopsy data and post-RT outcomes for 122 patients treated with a homogeneous dose to the prostate. For a test data set of 18 prostate cancer patients with pre-RT ADC images, we mapped the ADC data to the Gleason driven dose-responses by using probability distributions constructed from published Gleason score correlations with ADC data. We used the Gleason driven dose-responses to optimize dose painting prescriptions that maximize the tumor control probability (TCP) with equal average dose as for the learning sets homogeneous treatment dose.

Results: The dose painting prescriptions increased the estimated TCP compared to the homogeneous dose by 0–51% for the learning set and by 4–30% for the test set. The potential for individual TCP gains with dose painting correlated with increasing Gleason score spread and larger prostate volumes. The TCP gains were also found to be larger for patients with a low expected TCP for the homogeneous dose prescription.

Conclusions: We have from retrospective treatment data demonstrated a formalism that yield ADC driven dose painting prescriptions for prostate volumes that potentially can yield significant TCP increases without increasing dose burdens as compared to a homogeneous treatment dose. This motivates further development of the approach to consider more accurate ADC to Gleason mappings, issues with delivery robustness of heterogeneous dose distributions, and patient selection criteria for design of clinical trials.

National Category
Urology and Nephrology Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-147489 (URN)10.1080/0284186X.2017.1415457 (DOI)000430114000002 ()29260950 (PubMedID)
Funder
Swedish Cancer Society, 130632
Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-06-09Bibliographically approved
Brynolfsson, P., Löfstedt, T., Asklund, T., Nyholm, T. & Garpebring, A. (2018). Gray-level invariant Haralick texture features. Paper presented at 37th Meeting of the European-Society-for-Radiotherapy-and-Oncology (ESTRO), APR 20-24, 2018, Barcelona, SPAIN. Radiotherapy and Oncology, 127, S279-S280
Open this publication in new window or tab >>Gray-level invariant Haralick texture features
Show others...
2018 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 127, p. S279-S280Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:umu:diva-150493 (URN)10.1016/S0167-8140(18)30837-5 (DOI)000437723401139 ()
Conference
37th Meeting of the European-Society-for-Radiotherapy-and-Oncology (ESTRO), APR 20-24, 2018, Barcelona, SPAIN
Available from: 2018-11-01 Created: 2018-11-01 Last updated: 2018-11-01Bibliographically approved
Sandgren, K., Jonsson, J., Nyholm, T., Strandberg, S., Ögren, M., Axelsson, J., . . . Windmark, A. (2018). Histology correlation of in vivo [68Ga]PSMA-PET/MRI data of the prostate. Paper presented at 37th Meeting of the European-Society-for-Radiotherapy-and-Oncology (ESTRO), APR 20-24, 2018, Barcelona, SPAIN. Radiotherapy and Oncology, 127, S541-S541
Open this publication in new window or tab >>Histology correlation of in vivo [68Ga]PSMA-PET/MRI data of the prostate
Show others...
2018 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 127, p. S541-S541Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:umu:diva-150494 (URN)10.1016/S0167-8140(18)31288-X (DOI)000437723402226 ()
Conference
37th Meeting of the European-Society-for-Radiotherapy-and-Oncology (ESTRO), APR 20-24, 2018, Barcelona, SPAIN
Available from: 2018-11-01 Created: 2018-11-01 Last updated: 2018-11-01Bibliographically approved
Nyholm, T., Svensson, S., Andersson, S., Jonsson, J., Sohlin, M., Gustafsson, C., . . . Gunnlaugsson, A. (2018). MR and CT data with multiobserver delineations of organs in the pelvic area: Part of the Gold Atlas project. Medical physics (Lancaster), 45(3), 1295-1300
Open this publication in new window or tab >>MR and CT data with multiobserver delineations of organs in the pelvic area: Part of the Gold Atlas project
Show others...
2018 (English)In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 45, no 3, p. 1295-1300Article in journal (Refereed) Published
Abstract [en]

Purpose: We describe a public dataset with MR and CT images of patients performed in the same position with both multiobserver and expert consensus delineations of relevant organs in the male pelvic region. The purpose was to provide means for training and validation of segmentation algorithms and methods to convert MR to CT like data, i.e., so called synthetic CT (sCT).

Acquisition and validation methods: T1- and T2-weighted MR images as well as CT data were collected for 19 patients at three different departments. Five experts delineated nine organs for each patient based on the T2-weighted MR images. An automatic method was used to fuse the delineations. Starting from each fused delineation, a consensus delineation was agreed upon by the five experts for each organ and patient. Segmentation overlap between user delineations with respect to the consensus delineations was measured to describe the spread of the collected data. Finally, an open-source software was used to create deformation vector fields describing the relation between MR and CT images to further increase the usability of the dataset.

Data format and usage notes: The dataset has been made publically available to be used for academic purposes, and can be accessed from . Potential applicationsThe dataset provides a useful source for training and validation of segmentation algorithms as well as methods to convert MR to CT-like data (sCT). To give some examples: The T2-weighted MR images with their consensus delineations can directly be used as a template in an existing atlas-based segmentation engine; the expert delineations are useful to validate the performance of a segmentation algorithm as they provide a way to measure variability among users which can be compared with the result of an automatic segmentation; and the pairwise deformably registered MR and CT images can be a source for an atlas-based sCT algorithm or for validation of sCT algorithm.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
CT, MRI, open dataset, organs at risk, radiotherapy
National Category
Medical Image Processing
Identifiers
urn:nbn:se:umu:diva-146581 (URN)10.1002/mp.12748 (DOI)000427129700032 ()29322528 (PubMedID)
Available from: 2018-06-26 Created: 2018-06-26 Last updated: 2018-06-26Bibliographically approved
Fahlström, M., Blomquist, E., Nyholm, T. & Larsson, E.-M. (2018). Perfusion magnetic resonance imaging changes in normal appearing brain tissue after radiotherapy in glioblastoma patients may confound longitudinal evaluation of treatment response. Radiology and Oncology, 52(2), 143-151
Open this publication in new window or tab >>Perfusion magnetic resonance imaging changes in normal appearing brain tissue after radiotherapy in glioblastoma patients may confound longitudinal evaluation of treatment response
2018 (English)In: Radiology and Oncology, ISSN 1318-2099, E-ISSN 1581-3207, Vol. 52, no 2, p. 143-151Article in journal (Refereed) Published
Abstract [en]

Background: The aim of this study was assess acute and early delayed radiation-induced changes in normal-appearing brain tissue perfusion as measured with perfusion magnetic resonance imaging (MRI) and the dependence of these changes on the fractionated radiotherapy (FRT) dose level.

Patients and methods: Seventeen patients with glioma WHO grade III-IV treated with FRT were included in this prospective study, seven were excluded because of inconsistent FRT protocol or missing examinations. Dynamic susceptibility contrast MRI and contrast-enhanced 3D-T1-weighted (3D-T1w) images were acquired prior to and in average (standard deviation): 3.1 (3.3), 34.4 (9.5) and 103.3 (12.9) days after FRT. Pre-FRT 3D-T1w images were segmented into white-and grey matter. Cerebral blood volume (CBV) and cerebral blood flow (CBF) maps were calculated and co-registered patient-wise to pre-FRT 3D-T1w images. Seven radiation dose regions were created for each tissue type: 0-5 Gy, 5-10 Gy, 10-20 Gy, 20-30 Gy, 30-40 Gy, 40-50 Gy and 50-60 Gy. Mean CBV and CBF were calculated in each dose region and normalised (nCBV and nCBF) to the mean CBV and CBF in 0-5 Gy white-and grey matter reference regions, respectively.

Results: Regional and global nCBV and nCBF in white-and grey matter decreased after FRT, followed by a tendency to recover. The response of nCBV and nCBF was dose-dependent in white matter but not in grey matter.

Conclusions: Our data suggest that radiation-induced perfusion changes occur in normal-appearing brain tissue after FRT. This can cause an overestimation of relative tumour perfusion using dynamic susceptibility contrast MRI, and can thus confound tumour treatment evaluation.

Place, publisher, year, edition, pages
Walter de Gruyter, 2018
Keywords
perfusion MRI, radiation-induced changes, normal-appearing brain tissue, malignant gliomas
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-149009 (URN)10.2478/raon-2018-0022 (DOI)000433103400004 ()
Available from: 2018-06-15 Created: 2018-06-15 Last updated: 2018-06-15Bibliographically approved
Adjeiwaah, M., Bylund, M., Lundman, J. A., Thellenberg Karlsson, C., Jonsson, J. H. & Nyholm, T. (2018). Quantifying the effect of 3T MRI residual system and patient-induced susceptibility distortions on radiotherapy treatment planning for prostate cancer. International Journal of Radiation Oncology, Biology, Physics, 100(2), 317-324
Open this publication in new window or tab >>Quantifying the effect of 3T MRI residual system and patient-induced susceptibility distortions on radiotherapy treatment planning for prostate cancer
Show others...
2018 (English)In: International Journal of Radiation Oncology, Biology, Physics, ISSN 0360-3016, E-ISSN 1879-355X, Vol. 100, no 2, p. 317-324Article in journal (Refereed) Published
Abstract [en]

Purpose: To investigate the effect of magnetic resonance system- and patient-induced susceptibility distortions from a 3T scanner on dose distributions for prostate cancers.

Methods and Materials: Combined displacement fields from the residual system and patient-induced susceptibility distortions were used to distort 17 prostate patient CT images. VMAT dose plans were initially optimized on distorted CT images and the plan parameters transferred to the original patient CT images to calculate a new dose distribution.

Results: Maximum residual mean distortions of 3.19 mm at a radial distance of 25 cm and maximum mean patient-induced susceptibility shifts of 5.8 mm were found using the lowest bandwidth of 122 Hz per pixel. There was a dose difference of <0.5% between distorted and undistorted treatment plans. The 90% confidence intervals of the mean difference between the dCT and CT treatment plans were all within an equivalence interval of (−0.5, 0.5) for all investigated plan quality measures.

Conclusions: Patient-induced susceptibility distortions at high field strengths in closed bore magnetic resonance scanners are larger than residual system distortions after using vendor-supplied 3-dimensional correction for the delineated regions studied. However, errors in dose due to disturbed patient outline and shifts caused by patient-induced susceptibility effects are below 0.5%.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-142319 (URN)10.1016/j.ijrobp.2017.10.021 (DOI)000423097500011 ()29229326 (PubMedID)
Available from: 2017-11-27 Created: 2017-11-27 Last updated: 2018-06-09Bibliographically approved
Ménard, C., Paulson, E., Nyholm, T., McLaughlin, P., Liney, G., Dirix, P. & van der Heide, U. A. (2018). Role of Prostate MR Imaging in Radiation Oncology. The Radiologic clinics of North America, 56(2), 319-325
Open this publication in new window or tab >>Role of Prostate MR Imaging in Radiation Oncology
Show others...
2018 (English)In: The Radiologic clinics of North America, ISSN 0033-8389, E-ISSN 1557-8275, Vol. 56, no 2, p. 319-325Article in journal (Refereed) Published
Abstract [en]

The use of prostate MR imaging in radiotherapy continues to evolve. This article describes its current application in the selection of treatment regimens, integration in treatment planning or simulation, and assessment of response. An expert consensus statement from the annual MR in RT symposium is presented, as a list of 21 key quality indicators for the practice of MR imaging simulation in prostate cancer. Although imaging requirements generally follow PIRADSv2 guidelines, additional requirements specific to radiotherapy planning are described. MR imaging-only workflows and MR imaging-guided treatment systems are expected to replace conventional computed tomography-based practice, further adding specific requirements for MR imaging in radiotherapy.

Place, publisher, year, edition, pages
Saunders Elsevier, 2018
Keywords
Radiotherapy, Brachytherapy, Image-guidance, Prostate cancer, MR imaging
National Category
Cancer and Oncology Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-146453 (URN)10.1016/j.rcl.2017.10.012 (DOI)000427448400012 ()29420985 (PubMedID)
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-06-09Bibliographically approved
Brynolfsson, P., Axelsson, J., Holmberg, A., Jonsson, J., Goldhaber, D., Jian, Y., . . . Nyholm, T. (2018). Technical note: adapting a GE SIGNA PET/MR scanner for radiotherapy. Medical physics (Lancaster), 45(8), 3546-3550
Open this publication in new window or tab >>Technical note: adapting a GE SIGNA PET/MR scanner for radiotherapy
Show others...
2018 (English)In: Medical physics (Lancaster), ISSN 0094-2405, Vol. 45, no 8, p. 3546-3550Article in journal (Refereed) Published
Abstract [en]

Purpose: Simultaneous collection of PET and MR data for radiotherapy purposes are useful for, for example, target definition and dose escalations. However, a prerequisite for using PET/MR in the radiotherapy workflow is the ability to image the patient in treatment position. The aim of this work was to adapt a GE SIGNA PET/MR scanner to image patients for radiotherapy treatment planning and evaluate the impact on signal-to-noise (SNR) of the MR images, and the accuracy of the PET attenuation correction. Method: A flat tabletop and a coil holder were developed to image patients in the treatment position, avoid patient contour deformation, and facilitate attenuation correction of flex coils. Attenuation corrections for the developed hardware and an anterior array flex coil were also measured and implemented to the PET/MR system to minimize PET quantitation errors. The reduction of SNR in the MR images due to the added distance between the coils and the patient was evaluated using a large homogenous saline-doped water phantom, and the activity quantitation errors in PET imaging were evaluated with and without the developed attenuation corrections. Result: We showed that the activity quantitation errors in PET imaging were within ±5% when correcting for attenuation of the flat tabletop, coil holder, and flex coil. The SNR of the MRI images were reduced to 74% using the tabletop, and 66% using the tabletop and coil holders. Conclusion: We present a tabletop and coil holder for an anterior array coil to be used with a GE SIGNA PET/MR scanner, for scanning patients in the radiotherapy work flow. Implementing attenuation correction of the added hardware from the radiotherapy setup leads to acceptable PET image quantitation. The drop in SNR in MR images may require adjustment of the imaging protocols.

Place, publisher, year, edition, pages
Wiley-Blackwell Publishing Inc., 2018
Keywords
MRI, PET, PET, MR, quality assurance, radiotherapy
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:umu:diva-151405 (URN)10.1002/mp.13032 (DOI)000441292000009 ()29862522 (PubMedID)
Funder
VINNOVA
Available from: 2018-09-03 Created: 2018-09-03 Last updated: 2018-09-04Bibliographically approved
Organisations

Search in DiVA

Show all publications