Radiation injury to the spinal cord in head and neck cancers: does field arrangement have a role.

ABSTRACT

STUDY DESIGN: A study of eight cases of head and neck cancers, to see if the cord was getting a higher dose in the antero-posterior (A-P) fields, compared to the bilateral (B/L) fields. OBJECTIVE: Radiation damage to the spinal cord is a critical issue for the radiation oncologists. This study was conducted to evaluate, if the dose to the spinal cord is higher by the antero-posterior (A-P) fields, compared to the bilateral (B/L) fields. MATERIALS AND METHODS: Eight cases of head and neck cancer were taken in our study. Two beam arrangements were placed in the treatment planning system, the B/L and the A-P fields. The DVH's for the cord dose were recorded and compared in both plans, with a standard fraction size of 200 cGy/fraction. RESULTS: The mean dose to the spinal cord was 168.06 cGy in A-P arrangement, while it was 133.75 cGy in the B/L arrangement. CONCLUSION: A-P field arrangement in head and neck malignancies delivers a higher dose to the spinal cord. Therefore, we need to spare the cord at an earlier dose limit.