Source of Support: None, Conflict of Interest: None
lntracavitary brachytherapy by afterloading technique is the choice of the treatment for carcinoma of cervix. The dosimetry of the intracavitary brachytherapy is complex in the sense that the optimal dose that can be delivered to the tumour is dictated not only by the volume and extent of the tumour but also by close proximity of the dose limiting structures, such as the small and large intestines, rectum and bladder. Dosimetry of the rectum is comparatively easy as compared to bladder dosimetry. We have done measurement of bladder dose in 10 patients undergoing intracavitary brachytherapy applications. The
Ferrous Sulphate - Benzoic Acid - Xylenol Orange (FBX) chemical dosimeter system was used as a filling
solution in the Foley's catheter bulb for bladder dosimetry in place of distilled water. We observed the
bladder dose to be 10.5-12.5 Gy for a point A dose of 30 Gy.