SU-E-T-598: Variability of Computer-Generated Organ at Risk Contours as Part of An Automated Deformable Registration Workflow for Prostate Cancer

2013 ◽  
Vol 40 (6Part20) ◽  
pp. 343-343
Author(s):  
S Gardner ◽  
N Zaorsky ◽  
K Yamoah ◽  
Y Cui ◽  
Y Xiao ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Deformable Registration ◽  
Organ At Risk

scholarly journals EP-1839: Towards planning organ at risk volumes for rectum and bladder using cone beam CvT in prostate cancer

2017 ◽  
Vol 123 ◽  
pp. S1006-S1007
Author(s):  
R. Seuntjens ◽  
T. Convents ◽  
G. De Kerf ◽  
A . Sprangers ◽  
K. Van Belle ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Cone Beam ◽  
Organ At Risk

The impact of varying rectal contours on rectal dose in prostate cancer patients treated with hypofractionated radiation

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 15598-15598
Author(s):  
B. B. Joshua ◽  
S. Faria ◽  
H. Patrocinio ◽  
F. DeBlois ◽  
M. Duclos ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Radiation Treatment ◽  
Rectal Wall ◽  
Organs At Risk ◽  
Anal Verge ◽  
Rectal Toxicity ◽  
Rectal Dose ◽  
Organ At Risk ◽  
Definition Of

15598 Background: In curative radiation treatment of prostate cancer,the advent of 3DCRT has made a reduction in the incidence of normal tissue toxicities while optimizing tumor control. To optimize 3DCRT, the ICRU has published standard definitions of target volumes and organs at risk such that the tumor can receive the optimal dose with as little as possible dose to the organs at risk. However, the definition of the rectum as an organ at risk in radiation treatment of the prostate varies widely among institutions and so does the report of toxicities. We studied the effect of varying rectal contouring on rectal dose obtained from DVHs in a homogenous group of prostate cancer patients treated with hypo fractionationed radiation. Methods: 71 patients with favorable risk prostate cancer treated with a total of 66Gy in 3Gy/day fractionation.18 MV photons in a 5-field technique was used. None of the patients received hormonal therapy. Their treatment plans were archived and the rectum was re-contoured by a single investigator. 4 different contours were drawn to compare the rectal dose: i) the whole rectum from the anal verge to the recto sigmoid junction (WR); ii) the rectum from 1cm below the PTV to 1cm above (RPTV); iii) the rectal wall (i.e. the inner and outer rectal wall) from the anal verge to the recto sigmoid junction (RW); iv) the rectal wall from 1cm below the PTV to 1cm above (RWPTV) Results: There were significant differences in the median volume, minimum, mean rectal doses and dose to 50% of the volume, (p=0.0001). The whole rectum (WR) is having the lowest and the rectal wall with 1cm above and below the PTV (RWPTV) having the highest in all the parameters. The only parameter not significantly different among the 4 contours is the maximum rectal dose. Conclusion: the varied rectal contouring across different institutions is a possible reason for the broadly different reports of rectal toxicity after prostate irradiation. Our results suggest significant differences in rectal doses with varied contouring. Contouring the rectal wall only and limiting the volume to 1cm above and below the PTV confers the highest mean rectal dose. Comparison of rectal toxicity between institutions can only be meaningful if a consensual volume definition of the organ at risk is agreed upon. No significant financial relationships to disclose.

scholarly journals Comparison of different contouring definitions of the rectum as organ at risk (OAR) and dose–volume parameters predicting rectal inflammation in radiotherapy of prostate cancer: which definition to use?

2017 ◽  
Vol 90 (1070) ◽  
pp. 20160370 ◽  
Author(s):  
Mirko Nitsche ◽  
Werner Brannath ◽  
Matthias Brückner ◽  
Dirk Wagner ◽  
Alexander Kaltenborn ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Dose Volume ◽  
Organ At Risk

scholarly journals OC-0555: Organ at risk dose parameters increased by daily anatomic changes in prostate cancer SBRT

2016 ◽  
Vol 119 ◽  
pp. S266-S267
Author(s):  
M. Faasse-de Hoog ◽  
M.S. Hoogeman ◽  
J.J.M.E. Nuyttens ◽  
S. Aluwini
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Organ At Risk

scholarly journals Assessment of Knowledge-Based Planning for Prostate Intensity Modulated Proton Therapy

2021 ◽  
Author(s):  
Yihang Xu ◽  
Nellie Brovold ◽  
Jonathan Cyriac ◽  
Elizabeth Bossart ◽  
Kyle Padgett ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Proton Therapy ◽  
Volumetric Modulated Arc Therapy ◽  
Model Quality ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Knowledge Based ◽  
Knowledge Based Planning ◽  
Organ At Risk

Abstract Purpose To assess the performance of a proton-specific knowledge based planning (KBPP) model in creation of robustly optimized intensity-modulated proton therapy (IMPT) plans for treatment of patients with prostate cancer. Materials and Methods Forty-five patients with localized prostate cancer, who had previously been treated with volumetric modulated arc therapy, were selected and replanned with robustly optimized IMPT. A KBPP model was generated from the results of 30 of the patients, and the remaining 15 patient results were used for validation. The KBPP model quality and accuracy were evaluated with the model-provided organ-at-risk regression plots and metrics. The KBPP quality was also assessed through comparison of expert and KBPP-generated IMPT plans for target coverage and organ-at-risk sparing. Results The resulting R2 (mean ± SD, 0.87 ± 0.07) between dosimetric and geometric features, as well as the χ2 test (1.17 ± 0.07) between the original and estimated data, showed the model had good quality. All the KBPP plans were clinically acceptable. Compared with the expert plans, the KBPP plans had marginally higher dose-volume indices for the rectum V65Gy (0.8% ± 2.94%), but delivered a lower dose to the bladder (−1.06% ± 2.9% for bladder V65Gy). In addition, KBPP plans achieved lower hotspot (−0.67Gy ± 2.17Gy) and lower integral dose (−0.09Gy ± 0.3Gy) than the expert plans did. Moreover, the KBPP generated better plans that demonstrated slightly greater clinical target volume V95 (0.1% ± 0.68%) and lower homogeneity index (−1.13 ± 2.34). Conclusions The results demonstrated that robustly optimized IMPT plans created by the KBPP model are of high quality and are comparable to expert plans. Furthermore, the KBPP model can generate more-robust and more-homogenous plans compared with those of expert plans. More studies need to be done for the validation of the proton KBPP model at more-complicated treatment sites.

Propagation of target and organ at risk contours in radiotherapy of prostate cancer using deformable image registration

2010 ◽  
Vol 49 (7) ◽  
pp. 1023-1032 ◽  
Author(s):  
Sara Thörnqvist ◽  
Jørgen B. B. Petersen ◽  
Morten Høyer ◽  
Lise N. Bentzen ◽  
Ludvig Paul Muren
Keyword(s):  
Prostate Cancer ◽  
At Risk ◽  
Image Registration ◽  
Deformable Image Registration ◽  
Organ At Risk

A study on planning organ at risk volume for the rectum using cone beam computed tomography in the treatment of prostate cancer

2014 ◽  
Vol 39 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Ramachandran Prabhakar ◽  
Richard Oates ◽  
Daryl Jones ◽  
Tomas Kron ◽  
Jim Cramb ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Computed Tomography ◽  
At Risk ◽  
Cone Beam Computed Tomography ◽  
Cone Beam ◽  
Organ At Risk

scholarly journals Interfraction Anatomical Variability Can Lead to Significantly Increased Rectal Dose for Patients Undergoing Stereotactic Body Radiotherapy for Prostate Cancer

2016 ◽  
Vol 16 (2) ◽  
pp. 178-187 ◽  
Author(s):  
Michael Wahl ◽  
Martina Descovich ◽  
Erin Shugard ◽  
Dilini Pinnaduwage ◽  
Atchar Sudhyadhom ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Computed Tomography ◽  
At Risk ◽  
Stereotactic Body Radiotherapy ◽  
Organs At Risk ◽  
Anatomical Variation ◽  
High Dose ◽  
Megavoltage Computed Tomography ◽  
Organ At Risk ◽  
The Impact

Stereotactic body radiotherapy for prostate cancer is rapidly growing in popularity. Stereotactic body radiotherapy plans mimic those of high-dose rate brachytherapy, with tight margins and inhomogeneous dose distributions. The impact of interfraction anatomical changes on the dose received by organs at risk under these conditions has not been well documented. To estimate anatomical variation during stereotactic body radiotherapy, 10 patients were identified who received a prostate boost using robotic stereotactic body radiotherapy after completing 25 fractions of pelvic radiotherapy with daily megavoltage computed tomography. Rectal and bladder volumes were delineated on each megavoltage computed tomography, and the stereotactic body radiotherapy boost plan was registered to each megavoltage computed tomography image using a point-based rigid registration with 3 fiducial markers placed in the prostate. The volume of rectum and bladder receiving 75% of the prescription dose (V75%) was measured for each megavoltage computed tomography. The rectal V75% from the daily megavoltage computed tomographies was significantly greater than the planned V75% (median increase of 0.93 cm3, P < .001), whereas the bladder V75% on megavoltage computed tomography was not significantly changed (median decrease of −0.12 cm3, P = .57). Although daily prostate rotation was significantly correlated with bladder V75% (Spearman ρ = .21, P = .023), there was no association between rotation and rectal V75% or between prostate deformation and either rectal or bladder V75%. Planning organ-at-risk volume-based replanning techniques using either a 6-mm isotropic expansion of the plan rectal contour or a 1-cm expansion from the planning target volume in the superior and posterior directions demonstrated significantly improved rectal V75% on daily megavoltage computed tomographies compared to the original stereotactic body radiotherapy plan, without compromising plan quality. Thus, despite tight margins and full translational and rotational corrections provided by robotic stereotactic body radiotherapy, we find that interfraction anatomical variations can lead to a substantial increase in delivered rectal doses during prostate stereotactic body radiotherapy. A planning organ-at-risk volume-based approach to treatment planning may help mitigate the impact of daily organ motion and reduce the risk of rectal toxicity.

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