The benefits of employing computed tomography (CT) into the planning process of radiotherapy has been well established over the last 20 years. The cross sectional images provide invaluable information that enable clinicians to plan patients treatment with confidence. More recently there has been the development of the CT-simulator (CT-sim), however its place in the clinical setting has still to be established.

One of the most anticipated questions is “will the CT-simulator replace the present conventional treatment simulator as a tool for simulation?” There appear to be tremendous reasons why it should, but there are also many issues that need to be addressed.

This discussions aims to critically assess the practical and technical aspects of the new technology, by means of reviewing published literature. The aim is to decipher whether its introduction into the planning process is realistic and appropriate for all radiotherapy patients, and whether it has the possibility to replace the treatment simulator.

Issues concerned with image production, simulation (virtual), planning, cost, quality assurance (QA) and patient criteria (i.e. radical and palliative patients) have been reviewed. The Study concludes that the CT-sim has the realistic possibility to dramatically improve the treatment intent of all radiotherapy patients. Although there are situations where the treatment simulator appears to supersede the CT-sim, there still appears to be a place for it within the planning process.