Passage: To accurately plan the brachytherapy procedure, a thorough clinical examination is performed to understand the characteristics of the tumour. In addition, a range of imaging modalities can be used to visualise the shape and size of the tumour and its relation to surrounding tissues and organs. These include x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scans and magnetic resonance imaging (MRI). The data from many of these sources can be used to create a 3D visualisation of the tumour and the surrounding tissues.Using this information, a plan of the optimal distribution of the radiation sources can be developed. This includes consideration of how the source carriers (applicators), which are used to deliver the radiation to the treatment site, should be placed and positioned. Applicators are non-radioactive and are typically needles or plastic catheters. The specific type of applicator used will depend on the type of cancer being treated and the characteristics of the target tumour.This initial planning helps to ensure that ‘cold spots’ (too little irradiation) and ‘hot spots’ (too much irradiation) are avoided during treatment, as these can respectively result in treatment failure and side-effects.

Question: Which imaging modalities are used?
x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scans and magnetic resonance imaging (MRI).