Purpose: Brachytherapy is an integral part of cervical cancer treatment. Most parts of the developing world are still practicing point A based 2D planning. Optimising 2D brachytherapy planning makes good sense until they adopt newer MRI based 3D planning. The study was done to find out the optimum isodose distribution by changing brachytherapy application parameters.
Methods: 30 individual HDR brachytherapy sessions were done during July 2021-December 2021. Fletcher suit applicator was used, and the procedure was performed under sedation. Various parameters like ovoid separation, dose to bladder and rectum points as specified in ICRU-38 were recorded. Distance between bladder point and rectum point was noted in each brachytherapy session. 100% isodose line with maximum separation, both in AP and Lateral directions were recorded. All parameters are subjected to bi-variate analysis.
Results: All recorded parameters are co-related with the isodose coverage, both in AP and Lateral direction, and the most significant parameter affecting point A isodose distribution was inter-ovoid distance. Lateral isodose coverage increases with increase in ovoid separation up to approximately 25 to 30 mm, while AP isodose coverage remains constant throughout.
Conclusion: Ovoid separation of 25 to 30 mm gives optimum isodose coverage of point A in cervical cancer brachytherapy.