A radiotherapy planning CT scan is slightly different to a regular diagnostic CT scan. It allows radiographers to obtain 3D images of the area being treated in order to create individualised radiotherapy plans.
The scan itself will normally take between 10 to 15 minutes. However, sometimes there may be additional preparation for your scan which can mean that the appointment may last up to 2 hours. A few patients will require an injection of a contrast agent (IV contrast) and some patients will need to drink a liquid before the scan (oral contrast), these help highlight important areas the doctors may want to treat or avoid.
During the planning procedure, measurements will be taken for your radiotherapy record. During this process it will be necessary to place small marks, on your skin using a felt tip-type pen. At the end of the process, these marks will be made permanent, with your permission, by tattooing a small dot. This is so that prior to and during treatment you will be able to wash as normal without losing the marks.
Depending on the area being treated with radiotherapy, positron emission tomography (PET) scans and magnetic resonance imaging (MRI) scans may also be required for the planning of your treatment.
These are often performed by our colleagues in the diagnostic radiology departments and you will either be taken to these departments or contacted separately in order to arrange appointments.
For some treatment types or areas it may be necessary to have a device called a ‘shell’ or ‘mask’. This is used to keep mobile areas such as the head and neck area or limbs stable and still throughout treatment.
The process of making these will differ depending on what area of the body is being treated, when you arrive the staff will explain the procedure fully before starting and answer any questions you may have.
These appointments can vary from around 15 to 45 minutes and although they are often performed on the same day as your CT planning scan, on occasion you may be required to attend for a separate appointment.