Skip to main content Accessibility help
×
Home

Dosimetric variations for high-risk prostate cancer by VMAT plans due to patient’s weight changes

Published online by Cambridge University Press:  21 May 2019

David Miguel
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Victor de la Llana
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Daniel Martinez
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Angel del Castillo
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Delfín Alonso
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Jesús-María de Frutos
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Carlos Andrés
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Manuel Agulla
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Ricardo Torres
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Francisco López-Lara
Affiliation:
Hospital Clinico Universitario de Valladolid, Valladolid, Valladolid, Spain
Corresponding
E-mail address:

Abstract

Purpose:

The aim of this study is to investigate the impact of anatomical changes in prostate cancer patients on the target coverage when using 6 MV beams-VMAT therapy and to propose strategies that allow us to evaluate the dose or correct it by normalization without having to perform a new simulation.

Methods and materials:

Ten patients of high-risk prostate cancer were chosen for the study. All test plans were delivered using the same isocenter and monitor units as the original plan and compared against the original unedited plan. The expansion and contraction of body contours due to size changes was mimicked by increasing and decreasing the body contour with depths of −2, −1·5, …, 1·5, 2 cm, in the anterior, and both lateral directions of the patient. A total of 90 plans were evaluated, 9 for each patient. Dose-volume histogram statistics were extracted from each plan and normalized to prescription dose.

Results:

Weight changes resulted in considerable dose modifications to the target and critical structures. Plans were found to be varied with 2·9% ± 0·3% per cm SSD change for VMAT treatment with a correlation index close to one. Therefore, doses variations were linear to the changes of depth. Gamma index evaluation was performed for the 10 renormalized plans. All of them passed criteria of 3%/3 mm in at least 98.2% of points. Eight of them passed criteria in 99% points. Gamma index 4%/4 mm passed 100% points in all patients for the chosen region of interest.

Conclusions:

The dosimetry estimation presented in this study shows important data for the radiation oncology staff to justify whether a CT rescan is necessary or not when a patient experiences weight changes during treatment. Based on the results of our study, discrepancies between real dose and planned dose were >5% for 1·7 cm of difference in external contour in the anterior and both lateral directions of the patient.

Type
Original Article
Copyright
© Cambridge University Press 2019 

Access options

Get access to the full version of this content by using one of the access options below.

References

Torre, L A, Bray, F, Siegel, R L, Ferlay, J, Lortet-Tieulent, J, Jemal, A. Global cancer statistics, 2012. CA Cancer J Clin 2015; 65 (2): 87108.10.3322/caac.21262CrossRefGoogle ScholarPubMed
Mottet, N, Bellmunt, J, Bolla, M et al. EAU-ESTRO-SIOG Guidelines on Prostate Cancer. Part 1: Screening, Diagnosis, and Local Treatment with Curative Intent. Eur Urol 2017; 71 (4): 618629.10.1016/j.eururo.2016.08.003CrossRefGoogle ScholarPubMed
Pollack, A, Hanlon, A L, Horwitz, E M et al. Dosimetry and preliminary acute toxicity in the first 100 men treated for prostate cancer on a randomized hypofractionation dose escalation trial. Int J Radiat Oncol 2006; 64 (2): 518526.10.1016/j.ijrobp.2005.07.970CrossRefGoogle ScholarPubMed
Nguyen, N P, Davis, R, Bose, S R et al. International Geriatric Radiotherapy Group the IGR. Potential applications of image-guided radiotherapy for radiation dose escalation in patients with early stage high-risk prostate cancer. Front Oncol 2015; 5 (18): 17.10.3389/fonc.2015.00018CrossRefGoogle Scholar
Rodriguez, C, Freedland, S J, Deka, A et al. Body mass index, weight change, and risk of prostate cancer in the cancer prevention study II nutrition cohort. Cancer Epidemiol Biomarkers Prev 2007; 16 (1): 6369.10.1158/1055-9965.EPI-06-0754CrossRefGoogle ScholarPubMed
Bolze, M S, Fosmire, G J, Stryker, J A, Chung, C K, Flipse, B G. Taste acuity, plasma zinc levels, and weight loss during radiotherapy: a study of relationships. Radiology 1982; 144 (1): 163169.10.1148/radiology.144.1.7089250CrossRefGoogle ScholarPubMed
Houweling, A C, Fukata, K, Kubota, Y et al. The impact of interfractional anatomical changes on the accumulated dose in carbon ion therapy of pancreatic cancer patients. Radiother Oncol 2016; 119 (2): 319325.10.1016/j.radonc.2016.03.004CrossRefGoogle ScholarPubMed
Choi, H S, Jo, G S, Chae, J P et al. Defining the optimal time of adaptive replanning in prostate cancer patients with weight change during volumetric arc radiotherapy: a dosimetric and mathematical analysis using the gamma index. Comput Math Methods Med 2017; 2017: 4149591.10.1155/2017/4149591CrossRefGoogle ScholarPubMed
Pair, M L, Du, W, Rojas, H D et al. Dosimetric effects of weight loss or gain during volumetric modulated arc therapy and intensity-modulated radiation therapy for prostate cancer. Med Dosim 2013; 38 (3): 251254.10.1016/j.meddos.2013.02.004CrossRefGoogle ScholarPubMed
Chow, J C L, Jiang, R. Dosimetry estimation on variations of patient size in prostate volumetric-modulated arc therapy. Med Dosim 2013; 38 (1): 4247.10.1016/j.meddos.2012.05.005CrossRefGoogle ScholarPubMed
Chow, J C L, Jiang, R. Comparison of dosimetric variation between prostate IMRT and VMAT due to patient’s weight loss: patient and phantom study. Reports Pract Oncol Radiother 2013; 18 (5): 272278.10.1016/j.rpor.2013.05.003CrossRefGoogle ScholarPubMed
Low, D A, Harms, W B, Mutic, S, Purdy, J A. A technique for the quantitative evaluation of dose distributions. Med Phys 1998; 25 (5): 656661.10.1118/1.598248CrossRefGoogle ScholarPubMed
Low, D A, Harms, W B, Mutic, S, Purdy, J A. A technique for the quantitative evaluation of dose distributions. Med Phys 1998; 25 (5): 656661.10.1118/1.598248CrossRefGoogle ScholarPubMed
Mans, A, Schuring, D, Arends, M P et al. The NCS code of practice for the quality assurance and control for volumetric modulated arc therapy. Phys Med Biol 2016; 61 (19): 72217235.10.1088/0031-9155/61/19/7221CrossRefGoogle ScholarPubMed
Cutright, D, Gopalakrishnan, M, Roy, A, Panchal, A, Mittal, B B. DVH Analytics: a DVH database for clinicians and researchers. J Appl Clin Med Phys 2018; 19 (5): 413427.10.1002/acm2.12401CrossRefGoogle ScholarPubMed
Williams, G, Tobler, M, Leavitt, D. Pitfalls in normalization for intensity-modulated radiation therapy planning. Med Dosim 2005; 30 (4): 194200.10.1016/j.meddos.2005.06.003CrossRefGoogle ScholarPubMed
Kouloulias, V E. Quality assurance in radiotherapy. Eur J Cancer 2003; 39 (4): 415422.10.1016/S0959-8049(02)00461-6CrossRefGoogle ScholarPubMed
Klein, E E, Drzymala, R E, Purdy, J A, Michalski, J. Errors in radiation oncology: a study in pathways and dosimetric impact. J Appl Clin Med Phys 2005; 6 (3): 8194.10.1120/jacmp.v6i3.2105CrossRefGoogle ScholarPubMed

Full text views

Full text views reflects PDF downloads, PDFs sent to Google Drive, Dropbox and Kindle and HTML full text views.

Total number of HTML views: 14
Total number of PDF views: 75 *
View data table for this chart

* Views captured on Cambridge Core between 21st May 2019 - 28th January 2021. This data will be updated every 24 hours.

Hostname: page-component-898fc554b-5qzh9 Total loading time: 0.5 Render date: 2021-01-28T03:32:46.581Z Query parameters: { "hasAccess": "0", "openAccess": "0", "isLogged": "0", "lang": "en" } Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "metricsAbstractViews": false, "figures": false, "newCiteModal": false }

Send article to Kindle

To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Dosimetric variations for high-risk prostate cancer by VMAT plans due to patient’s weight changes
Available formats
×

Send article to Dropbox

To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

Dosimetric variations for high-risk prostate cancer by VMAT plans due to patient’s weight changes
Available formats
×

Send article to Google Drive

To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

Dosimetric variations for high-risk prostate cancer by VMAT plans due to patient’s weight changes
Available formats
×
×

Reply to: Submit a response


Your details


Conflicting interests

Do you have any conflicting interests? *