MEDRADSC 1F03 Lecture Notes - Lecture 10: External Beam Radiotherapy, Radioactive Decay, Brachytherapy

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 1F03
• Professor: Lyn Paddon

Document Summary

Principles of radiation therapy: radiation kills actively dividing cells, directly damages dna. Two ways to deliver therapy: ebrt: external beam radiation therapy, (cid:862)teletherapy(cid:863) Radiation delivered from a linear accelerator from outside the body. X-ray radiation must travel through normal tissues to treat a tumour. Intracavitary: permanent implant- surgi(cid:272)al pro(cid:272)edure to put seeds i(cid:374)to the patie(cid:374)t (wo(cid:374)"t take them out) Immobilization: finding the best position for their treatment. Immobilization devices are used to help the patient lay still in the treatment position: goal: optimal stable position + comfort, standard: head rests, knee wedges, special boards, leg immobilizers, custom: masks (shells) created / accessories - bolus, simulation. Images- from x-ray or ct scanning: ct simulator or conventional (x-ray) simulator used, radiation fields defined with patient in treatment position. Images taken of area to be treated: ct or x-rays, permanent marks (tattoos) placed on the patient for accurate alignment of fields.