DOSE DISTRIBUTION OVER THE RADIATION FIELD AND ORGANS OF THEBODY DURING RADIOTHERAPY PROCEDURES

摘要

Beam profile of the 60 Co teletherapy unit for 10 cm X 10 cm along central axis was measured to study the symmetry of the gamma beam and found that the average dose was 98.44+1.40 mGy. Output dose versus field size was also measured and values were found reasonable. Dose prescription to delivery was measured by placing TLD onto the treatment field or lung and cervix cancer patient which was found to be 39.16+2.98 Gy and 50.48+ 3.68 Gy respectively which are within 2 % and 0.17 % of the prescribed dose as 40.00 and 50.40 Gy respectively, reveals good agreement with the treatment planning. Six typical types of patients both male and female with cancers in lung, larynx, breast, cervix, esophagus and brain treated with 60 Co teletherapy were particularly considered for dose assessment at different critical organs of interest. It was observed that the doses to the lens of eye with a maximum value of 460.35+78.87 mGy for a larynx cancer patient to a minimum value of 30.80+4.00 mGy of a cervix cancer patient. Doses to the gonad vary ith a maximum value of 3810.80+389.76 mGy for a cervix cancer patient to a minimum value of 8.20+1.00 mGy for a brain cancer patient.