DEVELOPMENT OF A CLINICAL EVALUATION TOOL FOR LUNG SBRT TREATMENT PLAN QUALITY ASSURANCE

Abstract

Many studies on the effects of tumour motion on dose distribution first separate the entire tumour motion to 10 different time frames, each with the tumour in different positions. The complete delivery to each frame was calculated and 10 dose distributions were then averaged to give a single aggregate dose distribute for valuation. We propose a partial delivery to each time frame, the dose distribution to the tumour in each partial delivery was integrated to give a time dependent dose spatial distribution which is more representative of the real treatment scenario. A script was written in MATLAB to do dose accumulation of the different time frames. Results show that interplay effects exist for the target volume. Interplay effects worsens with increased amplitude of motion. This would need further evaluation in real patients. It further highlights the need for such tool to be used clinically to assess the robustness of the plan under motion interplay. This tool will provide the radiation oncologist a quick decision tool. It is to let the doctor decide if there's a need to rescan the patient or consider other alternatives with motion mitigation measures.