TY - JOUR
T1 - Deriving optimal planning organ at risk volume margins in prostate external beam radiotherapy
AU - Zhao, Yutong
AU - Ebert, Martin A.
AU - Waterhouse, David
AU - Goodall, Simon
AU - Rowshanfarzad, Pejman
AU - Fattahi, Shahin
PY - 2021/12
Y1 - 2021/12
N2 - Planning organ-at-risk volume (PRV) margins can be applied to the bladder and rectum in prostate external beam radiation therapy (EBRT), in order to incorporate the uncertainties resulting from their inter-fraction motion. For each of a total of 16 patients, the bladder and rectum were delineated on CBCT images for five treatment fractions in addition to the planning CT image set. The bladder and rectum boundary displacements across the images were measured and the frequency and size of organ boundary displacements were evaluated. Subsequently, PRV margins were created to cover a specific percentage of organ boundary motion for a specified percentage of the population. In this investigation, two bladder PRV margins were generated to deal with two bladder conditions of low and high-volume variation among fractions. A combined PRV margin was also generated for the rectum by separating the rectum into three parts and deriving independent PRV margins for each segment. Outward coverage and effectiveness metrics allowed evaluation of the margins.
AB - Planning organ-at-risk volume (PRV) margins can be applied to the bladder and rectum in prostate external beam radiation therapy (EBRT), in order to incorporate the uncertainties resulting from their inter-fraction motion. For each of a total of 16 patients, the bladder and rectum were delineated on CBCT images for five treatment fractions in addition to the planning CT image set. The bladder and rectum boundary displacements across the images were measured and the frequency and size of organ boundary displacements were evaluated. Subsequently, PRV margins were created to cover a specific percentage of organ boundary motion for a specified percentage of the population. In this investigation, two bladder PRV margins were generated to deal with two bladder conditions of low and high-volume variation among fractions. A combined PRV margin was also generated for the rectum by separating the rectum into three parts and deriving independent PRV margins for each segment. Outward coverage and effectiveness metrics allowed evaluation of the margins.
KW - Bladder
KW - External beam radiotherapy
KW - Planning organ-at-risk volume margins
KW - Prostate cancer
KW - Rectum
UR - http://www.scopus.com/inward/record.url?scp=85112832722&partnerID=8YFLogxK
U2 - 10.1007/s13246-021-01044-9
DO - 10.1007/s13246-021-01044-9
M3 - Article
C2 - 34410627
AN - SCOPUS:85112832722
SN - 2662-4729
VL - 44
SP - 1071
EP - 1080
JO - Physical and Engineering Sciences in Medicine
JF - Physical and Engineering Sciences in Medicine
IS - 4
ER -