Radiation Therapy Simulation and Planning

Tasmanian Health Service - Northern Region

The first appointment at the Holman Clinic will be for a simulation session. This involves a visit to a simulator machine. The simulator can do everything the treatment machines does except deliver the treatment.

This appointment takes 20 minutes to 1 hour depending on the area of the body being treated. Any relevant x-rays or scans  are brought to this appointment to assist the radiation therapists and Radiation Oncologists.

Usually two radiation therapists will be responsible for  the simulation session. Depending on the area of the body being treated, the patient may be asked to remove some items of clothing and be positioned on the simulation bed. Different types of equipment are used in order to keep the patient still during treatment. In the case of treatment to the head and neck area, a lightweight cast is made. This cast is made of plastic which is moulded to the shape of the face and neck. The patient is still able to hear, speak and breathe normally.

The radiation therapists will feel for bony landmarks and use a special marker to draw lines on the patients skin. The doctor will sometimes come in and discuss the treatment with the radiation therapists. He or she may also draw lines on the patients skin too. It does not matter if these markings wear off before treatment begins, as the staff will redraw them at first treatment and every other treatment day. The radiation therapists will take some measurements and then dim the lights. The simulation bed will be moved under the simulation machine and laser lights around the room will come on. The radiation therapist will align the skin markings with the lasers and when everything is straight they will take some x-ray images.

After the x-rays are done, the patient may be given some tiny tattoos. Tattoos are sometimes used in conjunction with skin marks. The small permanent black dots are less than the size of a freckle and are used to ensure that the treatment area is correctly located.

Photographs are taken of the patients treatment position and an identification photo will also be taken during the session. The photos assist the radiation therapists to set up the patient exactly the same each day.

Often a CT scan with the patient in exactly the same position as the simulation is done as well.. This scan is used for planning the radiation treatment. Usually it is not necessary for the patient to hold their breath or fast for this scan. A CT scan will usually take about 10 minutes and is carried out in the radiology department on level 3.

The radiation therapists and the radiation oncologist then determine an individual treatment plan. This may take a few days, so there may be a short delay before treatment begins.

W.P. Holman Clinic: an Introduction to your Treatment

An introductory video tour of treatment at the Holman Clinic.