A Dosimetric Comparison of ICRU Point Based Doses with 2CC Volume Doses of Bladder and Rectum in CT Based Planning of Intracavitary HDR Brachytherapy in Carcinoma Cervix

Aim: Main purpose of this study is to compare traditional ICRU bladder and rectum point doses with Doses received to 2cc volume of bladder and rectum in CT based planning of HDR brachytherapy in carcinoma cervix. Materials & Methods: Collected data of thirty five patients for whom intracavitary High Dose rate(HDR) brachytherapy planning done with a dose of 7Gy per fraction of total 3 fractions per patient on basis of ICRU bladder and rectal points. Then contoured complete bladder and rectum and then using DVH(Dose Volume Histogram) curves calculated D2cc, dose received by 2cm3 volume of the bladder and rectum separately according to GEC- ESTRO guidelines. Then compared point doses with D2cc doses of bladder and rectum using Pearson correlation test. Results: Mean dose of bladder point and rectal point is 4.40Gy and 3.31Gy per fraction respectively. The mean D2cc of Bladder and rectum is 6.63 and 4.70 respectively. Hence it found that mean D2cc of bladder and rectum is 1.50 and 1.41 times the bladder and rectum point doses respectively. Conclusion: Therefore this study suggests ICRU bladder and rectum points underestimates the particular dosage received by bladder and rectum. There is a correlation between both point doses and rectum doses. However bladder doses correlation is clinically significant while rectum doses are not clinically significant.