Dosimetric Comparison of Two Type Brachytherapy Planning Approaches in HDR Treatment of Carcinoma Uterine Cervix: Standard Library Plan Approaches vs. 3D CT Image Based Planning | Original Article

ABSTRACT:

Due to unavailability or limited resources of imaging modality some centres in low and middle income countries (LMICs) are still unable to adopt image based treatment planning in brachytherapy practice. This study aimed to compare the volumetric dose differences between images based planning and standard library plan (SLP) approaches to find out the feasibility of using SLP approaches for HDR treatment planning in LMICs. Total ninety four plans of 47 patients image based plan were evaluated retrospectively. For each set of image based plans, one additional set of plans were generated by applying dwell positions and dwell times of SLP approach on reconstructed applicator position of CT image data of each patient. The mean dose of bladder D2cc, D1cc and D0.1cc were higher by 0.03 Gy, 0.4 Gy and 0.06 Gy respectively in SLP approach rather than image based plan (p-value > 0.05). For rectum and sigmoid colon the mean dose of D2cc, D1cc and D0.1cc were significantly increases in SLP approach rather than image based plan. Higher increase for D0.1cc mean dose of rectum (0.12 Gy, 2.19) and sigmoid colon (0.12 Gy, 1.69) were found when SLP approach was used in place of image based plan. The results of this study shows that mean doses of target and OAR (bladder, rectum and sigmoid colon) are increases with SLP approach. The increase dose to rectum, bladder and sigmoid colon in SLP approach may lead to enhance the toxicity and hence affect the quality of life. The results of this study emphasized that if limited resource settings use SLP approach the proper applicator placements, adequate packing and other accounting factors should be considered carefully.