Treatment Plan Evaluation by Radiobiological Model in Radiotherapy Treatment Planning Computer

Abstract

The purpose of radiotherapy treatment planning is to design the best irradiation technique for the patient. After the treatment plans are performed by medical physicists, the oncologist evaluates the plan. In physical evaluation, the criteria are determined in terms of doses and irradiated volumes by using the evaluation tools such as dose distribution, dose volume histogram (DVH) and dose statistics. This is insuffi cient to predict any biological end point of radiotherapy. Recently, the radiobiological models are introduced in commercial treatment planning. The purpose of this study was the use of radiobiological model in treatment planning system to evaluate treatment plan. The plans of 34 patients treated with 3D-CRT were irradiated. The biological index such as TCP, NTCP, EUD and P+ were calculated for each treatment plan and the P+ values were then compared. In each case, the best plan with highest P+ value was examined whether it was chosen for patient treatment. The results revealed that of 16 patients (47 percents) the plan with highest P+ value was selected. Statistical analysis showed signifi cant difference between the treatment plan evaluation by using radiobiological model and without using radiobiological model (p value ≤ 0.05). The radiobiological model can help choosing the best treatment plan, therefore, the treatment outcome and a quality of life will be improved as a consequence