Source of Support: None, Conflict of Interest: None
Radiotherapy plays an important role in the treatment of patients with breast cancer. The rationale for post mastectomy radiotherapy is to prevent recurrence of cancer in the chest wall, skin, mastectomy scar and the regional nodes (supra clavicular nodes and internal mammary nodes). Complexity of the shape and position of the irradiated volume of carcinoma breast, make it necessary to give a careful attention to the positioning of the patient and the technique involved. Patient has to be positioned carefully everyday in order to reduce doses to organ such as lung, contra lateral breast and thyroid. Radiation dose measurement is done for 20 cases with carcinoma breast using semiconductor detectors. The diode is kept in the central point of the entry field and the dose is measured in the case of tangential field treatment. Tangential field treatment is carried out using half beam block to reduce dose to the underlying lung tissue. The exit dose is also measured on the same day. The dose through supra clavicular field (SCF) is given in 20 equal intervals of dose and the dose is measured using the semiconductor detectors. Every day dose is compared and the variation, if any, is estimated. It is found that in about 50% of the treated cases more than 5% variation exists in the case of tangential treatment technique and less than 5% for SCF tratment.