Abstract:
The most important criterion of radiotherapy is accuracy in all planning stage and in delivery of the prescribed treatment. In head and neck tumour especially in radical irradiation, a high dose of radiation was delivered to the tumour site. Thyroid gland most of the time found inside the radiation field and hence might receive a substantial amount of radiation which may alter the function of thyroid. Out of 80 patient’s who were received a radical radiation dose in range of 6000-6500cGy at radiation and isotopes center of Khartoum RICK and planned for conventional radiotherapy, Patients treated radically under isocentric cobalt 60, blood sample are taking from patient and RIA used to analyze level of thyroid hormones .Day’s method used to calculate distant between thyroid and other organs. as assessment for thyroid hormones level T4, T3 and TSH have been studied after receiving average dose of 2653.33 cGy. Accordingly the analysis of the data showed that the thyroid hormones (T4 and T3) decrease as a result of irradiation and the reduction persists following radiation dose in a linear form by a factor of 0.0002nmol/cGy and 0.0074 nmol/cGy respectively, while the TSH increase following radiation dose increment and the increment factor was 0.0005 nmol/cGy. The researcher recommended; firstly assessment of thyroid hormones in head and neck cancer patient after complete treatment .Secondary using of CT simulator will reduce the amount of dose serviced by thyroid.
