Assessment of scattered dose contribution to healthy tissue in radiation therapy using water phantom

Abstract

In cancer therapy using gamma radiation one of the limiting factors in dose delivery is the safety of the healthy tissues and organs around the cancerous mass. Better collimation and dose fractionation are employed to achieve this. In the present paper results of scattered dose to healthy tissues around the incident beam cross-section or beam boundaries have been estimated using IAEA standard water phantom and Co-60 incident radiation. It has been observed that scattered dose to healthy tissues increases linearly from 4% to 7% of the incident dose of 185 cGy to 200 cGy at the centre of the beam, at 5 cm depth in water, as we increase the incident beam field size from 5 cm x 5 cm to 10 cm x 10 cm. Also the maximum unwanted scattered dose for any field size remains closer to the incident beam boundaries.

Keywords

• scattered dose
• cancer therapy
• healthy tissue
• radiation therapy
• water phantom