TY - JOUR
T1 - Three-dimensional dosimetric considerations from different point a definitions in cervical cancer low-dose-rate brachytherapy
AU - Zhang, Miao
AU - Chen, Ting
AU - Kim, Leonard H.
AU - Nelson, Carl
AU - Gabel, Molly
AU - Narra, Venkat
AU - Haffty, Bruce
AU - Yue, Ning J.
PY - 2013
Y1 - 2013
N2 - Purpose: To investigate the dosimetric difference due to the different point A definitions in cervical cancer lowdose- rate (LDR) intracavitary brachytherapy. Material and methods: Twenty CT-based LDR brachytherapy plans of 11 cervical patients were retrospectively reviewed. Two plans with point As following the modified Manchester system which defines point A being 2 cm superior to the cervical os along the tandem and 2 cm lateral (Aos), and the American Brachytherapy Society (ABS) guideline definition in which the point A is 2 cm superior to the vaginal fornices instead of os (A ovoid) were generated. Using the same source strength, two plans prescribed the same dose to Aos and Aovoid. Dosimetric differences between plans including point A dose rate, treatment volume encompassed by the prescription isodose line (TV), and dose rate of 2 cc of the rectum and bladder to the prescription dose were measured. Results: On average Aovoid was 8.9 mm superior to Aos along the tandem direction with a standard deviation of 5.4 mm. With the same source strength and arrangement, Aos dose rate was 19% higher than Aovoid dose rate. The average TV(Aovoid) was 118.0 cc, which was 30% more than the average TV(Aos) of 93.0 cc. D2cc/D(Aprescribe) increased from 51% to 60% for rectum, and increased from 89% and 106% for bladder, if the prescription point changed from Aos to A ovoid. Conclusions: Different point A definitions lead to significant dose differences. Careful consideration should be given when changing practice from one point A definition to another, to ensure dosimetric and clinical equivalency from the previous clinical experiences.
AB - Purpose: To investigate the dosimetric difference due to the different point A definitions in cervical cancer lowdose- rate (LDR) intracavitary brachytherapy. Material and methods: Twenty CT-based LDR brachytherapy plans of 11 cervical patients were retrospectively reviewed. Two plans with point As following the modified Manchester system which defines point A being 2 cm superior to the cervical os along the tandem and 2 cm lateral (Aos), and the American Brachytherapy Society (ABS) guideline definition in which the point A is 2 cm superior to the vaginal fornices instead of os (A ovoid) were generated. Using the same source strength, two plans prescribed the same dose to Aos and Aovoid. Dosimetric differences between plans including point A dose rate, treatment volume encompassed by the prescription isodose line (TV), and dose rate of 2 cc of the rectum and bladder to the prescription dose were measured. Results: On average Aovoid was 8.9 mm superior to Aos along the tandem direction with a standard deviation of 5.4 mm. With the same source strength and arrangement, Aos dose rate was 19% higher than Aovoid dose rate. The average TV(Aovoid) was 118.0 cc, which was 30% more than the average TV(Aos) of 93.0 cc. D2cc/D(Aprescribe) increased from 51% to 60% for rectum, and increased from 89% and 106% for bladder, if the prescription point changed from Aos to A ovoid. Conclusions: Different point A definitions lead to significant dose differences. Careful consideration should be given when changing practice from one point A definition to another, to ensure dosimetric and clinical equivalency from the previous clinical experiences.
UR - https://www.scopus.com/pages/publications/84892724734
UR - https://www.scopus.com/inward/citedby.url?scp=84892724734&partnerID=8YFLogxK
U2 - 10.5114/jcb.2013.38836
DO - 10.5114/jcb.2013.38836
M3 - Article
AN - SCOPUS:84892724734
SN - 1689-832X
VL - 5
SP - 222
EP - 226
JO - Journal of Contemporary Brachytherapy
JF - Journal of Contemporary Brachytherapy
IS - 4
ER -