Journal of Medical Physics
TECHNICAL NOTE
Year
: 2018  |  Volume : 43  |  Issue : 2  |  Page : 136--140

Interfraction dose variations in organs at risk during CT-based high-dose-rate brachytherapy in locally advanced carcinoma cervix: An early experience of a tertiary care Center


Neelam Sharma1, Manoj K Semwal2, Abhishek Purkayastha1 
1 Department of Radiation Oncology, Army Hospital Research and Referral, New Delhi, India
2 Department of Radiation Physics, Army Hospital Research and Referral, New Delhi, India

Correspondence Address:
Dr. Neelam Sharma
Department of Radiation Oncology, Army Hospital Research and Referral, Dhaula Kuan, Delhi Cantt, New Delhi - 110 010
India

Purpose: Dose received by organs at risk (OAR) in high-dose-rate (HDR) intracavitary brachytherapy (ICBT) for locally advanced cervical cancer impacts the late toxicity profile of the treatment. In the present study, we analyzed the inter-fraction variations of the minimum dose received by the most irradiated 2cc volumes (D2cc) of the OARs in ICBT. Methods and Materials: This prospective study included 40 patients with cervical cancer stage FIGO IIB-IVA treated with HDR ICBT and concomitant chemoradiotherapy with Computerized tomography (CT)- based three-dimensional planning. In addition, for 20 (of the 40) patients, the first fraction plan was superimposed on the second fraction images for studying its dosimteric impact on the OAR. The D2ccdata for the OAR was statistically analyzed for interfraction variations with Chi-square test or Fisher exact test as applicable. Paired t-test was used to compare the difference in means for the D2ccvalues between the three fractions. Results: The interfraction variations of the D2ccvalues of the OAR were statistically insignificant having P = 0.41, 0.8, and 0.20 for bladder, rectum, and sigmoid, respectively. Further, in 6 out of 20 cases, wherein first fraction plan was superimposed on second fraction images, the OAR doses exceeded the prescribed tolerance limits. Conclusion: We did not find variations in the OAR doses when each fraction was planned and treated individually. However, we found that if a single plan is used to treat subsequent fractions, OAR doses may exceed tolerance in about 30% of the cases. We believe that a larger sample size with improved compliance of bladder and bowel protocols would be needed to arrive at definitive conclusions.


How to cite this article:
Sharma N, Semwal MK, Purkayastha A. Interfraction dose variations in organs at risk during CT-based high-dose-rate brachytherapy in locally advanced carcinoma cervix: An early experience of a tertiary care Center.J Med Phys 2018;43:136-140


How to cite this URL:
Sharma N, Semwal MK, Purkayastha A. Interfraction dose variations in organs at risk during CT-based high-dose-rate brachytherapy in locally advanced carcinoma cervix: An early experience of a tertiary care Center. J Med Phys [serial online] 2018 [cited 2020 Jun 2 ];43:136-140
Available from: http://www.jmp.org.in/article.asp?issn=0971-6203;year=2018;volume=43;issue=2;spage=136;epage=140;aulast=Sharma;type=0