Spatial and dosimetric evaluation of residual distortions of prostate and seminal vesicle bed after image‐guided definitive and postoperative radiotherapy of prostate cancer with endorectal balloon
| Autor: | Martin Stuschke, Christoph Pöttgen, Maja Guberina, Sabine Levegrün, Konstantinos Xydis, Jehad Abu Jawad |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Male
accumulated dose distributions medicine.medical_treatment Medizin Postoperative radiotherapy Residual 030218 nuclear medicine & medical imaging 03 medical and health sciences Prostate cancer 0302 clinical medicine Seminal vesicle Endorectal balloon Prostate medicine Radiation Oncology Physics Humans Radiology Nuclear Medicine and imaging Instrumentation Cell survival Radiation business.industry Radiotherapy Planning Computer-Assisted Prostatic Neoplasms Seminal Vesicles residual distortions Radiotherapy Dosage image‐guided radiotherapy medicine.disease prostate cancer Radiation therapy medicine.anatomical_structure 030220 oncology & carcinogenesis Radiotherapy Intensity-Modulated time series Nuclear medicine business Radiotherapy Image-Guided |
| Zdroj: | Journal of Applied Clinical Medical Physics |
| ISSN: | 1526-9914 |
| Popis: | Purpose: To quantify daily residual deviations from the planned geometry after image-guided prostate radiotherapy with endorectal balloon and to evaluate their effect on the delivered dose distribution. Methods: Daily kV-CBCT imaging was used for online setup-correction in six degrees of freedom (6-dof) for 24 patients receiving definitive (12 RTdₑf patients) or postoperative (12 RTpₒstₒp patients) radiotherapy with endorectal balloon (overall 739 CBCTs). Residual deviations were evaluated using several spatial and dosimetric variables, including: (a) posterior Hausdorff distance HDpost (=maximum distance between planned and daily CTV contour), (b) point Pwₒrst with largest HDpost over all fractions, (c) equivalent uniform dose using a cell survival model (EUDSF) and the generalized EUD concept (gEUDₐ with parameter a = −7 and a = −20). EUD values were determined for planned ((Formula presented.)), daily ((Formula presented.)), and delivered dose distributions ((Formula presented.)) for plans with 6 mm (=clinical plans) and 2 mm CTV-to-PTV margin. Time series analyses of interfractional spatial and dosimetric deviations were conducted. Results: Large HDpost values ≥ 12.5 mm (≥15 mm) were observed in 20/739 (5/739) fractions distributed across 7 (3) patients. Points Pwₒrst were predominantly located at the posterior CTV boundary in the seminal vesicle region (16/24 patients, 6/7 patients with HDpost ≥ 12.5 mm). Time series analyses revealed a stationary white noise characteristic of HDpost and relative dose at Pwₒrst. The EUDSF difference between planned and accumulated dose distributions was |
| Databáze: | OpenAIRE |
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