Pelvic Normal Tissue Contouring Guidelines for Radiation Therapy: A Radiation Therapy Oncology Group Consensus Panel Atlas

Gay, Hiram A.; Barthold, H. Joseph; O’Meara, Elizabeth; Bosch, Walter; Naqa, Issam El; Al-Lozi, Rawan; Rosenthal, Seth A.; Lawton, C.A.; Lee, W. Robert; Sandler, Howard M.; Zietman, Anthony; Myerson, Robert J.; Dawson, Laura A.; Willett, Christopher G.; Kachnic, Lisa A.; Jhingran, Anuja; Portelance, Lorraine; Ryu, Janice; Small, William; Gaffney, David K.; Viswanathan, Akila; Michalski, Jeff M.

doi:10.1016/j.ijrobp.2012.01.023

Cited by 430 publications

(300 citation statements)

References 21 publications

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“…Contouring was outlined according to the RTOG guidelines (10) for a male pelvis. To reduce the interuser variability for contouring, the same investigator completed all contouring per patient.…”

Section: Methodsmentioning

confidence: 99%

Dosimetric and volumetric changes in the rectum and bladder in patients receiving CBCT‐guided prostate IMRT: analysis based on daily CBCT dose calculation

Pearson

Gill

Campbell

et al. 2016

J Applied Clin Med Phys

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Delivered dose can be calculated by transferring the planned treatment beams onto the daily CBCT. Bladder and rectum volumetric doses were calculated and correlated to the daily bladder and rectum fullness. Patients for this study underwent hypofractionated prostate IMRT to 70 Gy in 28 fractions. Daily CBCT was utilized for image guidance. A clinically acceptable plan was created using a CTV‐to‐PTV uniform margin of 5 mm. Image fusion was performed to transfer the bladder and rectum contours onto each CBCT. Contours were then edited to match the anatomy of each CBCT. Using the daily treatment isocenter, the planned beams were transferred onto the CBCT and daily and cumulative DVHs calculated. For the results a total of 168 daily CBCTs were evaluated. The bladder was found to be smaller for 74.7% of the 168 daily CBCTs accessed in this study. This reduction in volume correlated to an increase in the cumulative bladder V70 Gy from 9.47% on the planning CT to 10.99% during treatment. V70Gy for the rectum was 7.27% on the planning CT, when all six patients were averaged, and increased to 11.56% on the average of all daily treatment CBCTs. Increases in volumetric rectum dose correlated with increases in rectal volume. For one patient, the rectum and bladder absolute V70 Gy, averaged over the course of treatment, increased by 295% and 61%, respectively. Larger variations in the daily bladder and rectal volume were observed and these correlated to large deviations from the volumetric dose received by these structures. In summary, bladder and rectum volume changes during treatment have an effect on the cumulative dose received by these organs. It was observed that the volumetric dose received by the bladder decreases as the volume of the bladder increases. The inverse was true for the rectum.PACS number(s): 87.55.dk‐, 87.57.Q‐

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Section: Methodsmentioning

confidence: 99%

Dosimetric and volumetric changes in the rectum and bladder in patients receiving CBCT‐guided prostate IMRT: analysis based on daily CBCT dose calculation

Pearson

Gill

Campbell

et al. 2016

J Applied Clin Med Phys

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“…The radiation oncologist delineated on all CTs the gross tumor volume (GTV), corpus-uterus, cervix, upper part of the vagina and elective lymph nodes. Also, the body, bowel cavity, as a surrogate for small bowel, rectum, kidneys and bladder were delineated using RTOG guidelines [14]. The primary CTV (pCTV) encompassed the GTV, cervix, corpus-uterus and upper part of the vagina.…”

Section: Patients and Imagingmentioning

confidence: 99%

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

et al. 2016

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Background Image-guided adaptive proton therapy (IGAPT) can potentially be applied to take into account interfraction motion while limiting organ at risk (OAR) dose in cervical cancer radiation therapy (RT). In this study, the potential dosimetric advantages of IGAPT compared with photonbased image-guided adaptive RT (IGART) were investigated. Material and methods For 13 cervical cancer patients, full and empty bladder planning computed tomography (CT) images and weekly CTs were acquired. Based on both primary clinical target volumes (pCTVs) [i.e. gross tumor volume (GTV), cervix, corpus-uterus and upper part of the vagina] on planning CTs, the pretreatment observed full range primary internal target volume (pITV) was interpolated to derive pITV subranges. Given corresponding ITVs (i.e. pITVs including lymph nodes), patient-specific photon and proton plan libraries were generated. Using all weekly CTs, IGART and IGAPT treatments were simulated by selecting library plans and recalculating the dose. For each recalculated IGART and IGAPT fraction, CTV (i.e. pCTV including lymph nodes) coverage was assessed and differences in fractionated substitutes of dose-volume histogram (DVH) parameters (V 15Gy , V 30Gy , V 45Gy , D mean , D 2cc ) for bladder, bowel and rectum were tested for significance (Wilcoxon signed-rank test). Also, differences in toxicity-related DVH parameters (rectum V 30Gy , bowel V 45Gy ) were approximated based on accumulated dose distributions. Results In 92% (96%) of all recalculated IGAPT (IGART) fractions adequate CTV coverage (V 95% 498%) was obtained. All dose parameters for bladder, bowel and rectum, except the fractionated substitute for rectum V 45Gy , were improved using IGAPT. Also, IGAPT reduced the mean dose to bowel, bladder and rectum significantly (p50.01). In addition, an average decrease of rectum V 30Gy and bowel V 45Gy indicated reductions in toxicity probabilities when using IGAPT. Conclusion This study demonstrates the feasibility of IGAPT in cervical cancer using a plan-library based plan-of-the-day approach. Compared to photon-based IGART, IGAPT maintains target coverage while significant dose reductions for the bladder, bowel and rectum can be achieved.

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“…Table 1 shows the different margins applied to the contours that were created for each strategy. In addition to the PTVs, the rectum and bowel cavity were delineated for both strategies on the planning CT scan according to RTOG delineation guidelines [13]. For each set of PTVs, a dual arc volumetric modulated arc therapy (VMAT) plan was created, with standard planning objectives to aim for homogenous doses to the PTVs, while keeping dose to the organs at risk (OARs) as low as possible.…”

Section: Treatment Planningmentioning

confidence: 99%

A biological modeling based comparison of two strategies for adaptive radiotherapy of urinary bladder cancer

et al. 2016

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Background Adaptive radiotherapy is introduced in the management of urinary bladder cancer to account for day-to-day anatomical changes. The purpose of this study was to determine whether an adaptive plan selection strategy using either the first four cone beam computed tomography scans (CBCT-based strategy) for plan creation, or the interpolation of bladder volumes on pretreatment CT scans (CT-based strategy), is better in terms of tumor control probability (TCP) and normal tissue sparing while taking the clinically applied fractionation schedules also into account. Material and methods With the CT-based strategy, a library of five plans was created. Patients received 55 Gy to the bladder tumor and 40 Gy to the non-involved bladder and lymph nodes, in 20 fractions. With the CBCT-based strategy, a library of three plans was created, and patients received 70 Gy to the tumor, 60 Gy to the bladder and 48 Gy to the lymph nodes, in 30-35 fractions. Ten patients were analyzed for each adaptive plan selection strategy. TCP was calculated applying the clinically used fractionation schedules, as well as a rescaling of the dose from 55 to 70 Gy for the CT-based strategy. For rectum and bowel, equivalent doses in 2 Gy fractions (EQD2) were calculated. Results The CBCT-based strategy resulted in a median TCP of 75%, compared to 49% for the CT-based strategy, the latter improving to 72% upon rescaling the dose to 70 Gy. A median rectum V30Gy (EQD2) of 26% [interquartile range (IQR): 8-52%] was found for the CT-based strategy, compared to 58% (IQR: 55-73%) for the CBCT-based strategy. Also the bowel doses were lower with the CT-based strategy. Conclusions Whereas the higher total bladder TCP for the CBCT-based strategy is due to prescription differences, the adaptive strategy based on CT scans results in the lowest rectum and bowel cavity doses.

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Pelvic Normal Tissue Contouring Guidelines for Radiation Therapy: A Radiation Therapy Oncology Group Consensus Panel Atlas

Cited by 430 publications

References 21 publications

Dosimetric and volumetric changes in the rectum and bladder in patients receiving CBCT‐guided prostate IMRT: analysis based on daily CBCT dose calculation

Dosimetric and volumetric changes in the rectum and bladder in patients receiving CBCT‐guided prostate IMRT: analysis based on daily CBCT dose calculation

Dosimetric advantages of proton therapy compared with photon therapy using an adaptive strategy in cervical cancer

A biological modeling based comparison of two strategies for adaptive radiotherapy of urinary bladder cancer

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