TITLE:
Organ at Risk Doses during High Dose Rate Intracavitary Brachytherapy for Cervical Cancer: A Dosimetric Study
AUTHORS:
N. V. Vinin, Joneetha Jones, V. T. Ajas, Geetha Muttath, C. A. Suja, E. K. Nabeel Yahiya, P. N. Shoaib Nawaz, Arun P. Narendran, P. Shimjith
KEYWORDS:
Intracavitary Brachytherapy, Carcinoma Cervix, Organ at Risk, High Dose Rate Brachytherapy
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.4,
October
12,
2018
ABSTRACT: Background: Treatment
of Cervical cancer includes a combination of external beam radiotherapy (EBRT) with intracavitary brachytherapy (ICBT).
ICBT helps to boost radiation dose to primary disease. Organs like rectum, bladder, sigmoid
and small bowel lie close to the cervix region and these organs receive dose from EBRT as
well as ICBT and we want to know the dose to these organ
at risk (OAR). Materials & Methods: Dosimetric
details of 174 ICBT applications done in 58 patients were retrospectively
analysed. All patients received EBRT dose of 50.4 Gy in 28 fractions. All
patients had ICBT, three sessions with 7 Gy prescribed to point A. Dosimetric data including
dose to right and left point A and dose to OARs were recorded from Oncentra
Planning System. Results: Mean
dose to point A on right side was 6.89 Gy and left side was 6.91 Gy. Mean D2cc
dose to rectum, bladder, sigmoid and small bowel
was 3.5 Gy, 5.25 Gy, 4.75 Gy and 4.2 Gy
respectively. Mean EQD2 dose combining EBRT and ICBT in point A was 78.7 Gy on
right side and 79 Gy on
left side. Mean EQD2 doses to D2cc of rectum, bladder, sigmoid and small bowel
was 62 Gy, 74.4 Gy, 70.5 Gy and 66.5 Gy respectively. Conclusion: From
the results of this dosimetric study it is evident that OARs like rectum, sigmoid, bladder & bowel are receiving
only acceptable doses of radiation using point A prescribed CT based ICBT
planning. Hence with regards to OAR doses, CT based ICBT planning with dose
prescribed to point A is a feasible option.