A Novel Method of 3-Dimensional Radiotherapy for Head-and-Neck Cancer Treatment

Abstract

This study intends to develop a novel method to resolve the problem of extreme dose inhomogeneity in the photon-electron abutting fields in the 3DCRT (3-Dimensinal Conformal Radiation Therapy) for head-and-neck cancer. Firstly, the conventional method using bilateral irradiation of photon and electron beam is reviewed, concerning the inhomogeneity of dose distribution, i.e., the root cause of a hot and a cold spot. Second, based on the root causes in the conventional plan, an alternative method is developed using oblique irradiation of photon and electron beam. Finally, a comparative analysis between both plans is performed to assess feasibility of the new method. From the results of qualitative comparison, it is shown that that the new method can reduce dramatically the maximum dose inside the irradiation fields for all the target region. The volume fractions of hot regions receiving higher dose than the prescribed dose are also significantly decreased. It is also noted that the new method does not give rise to increase in dose to spinal cord. The obtained results suggest that the new method using oblique irradiation of both photon and electron beam can reduce significantly improve the dose inhomogeneity inside radiation field for treatment of head and neck cancer.