Once the patient has decided to go ahead with radiotherapy, they must be prepared for the treatment. The institute’s modern radiotherapy equipment ensures treatment with millimetre accuracy. What’s more, the amount of radiation applied to the designated body part can also be exactly calculated to within 1-2%. The art of radiotherapy lies in providing the necessary dose exactly where the tumour cells are (still) present and to avoid damaging those areas which are not affected by the cancer. It is also vital that each radiotherapy treatment be carried out under exactly the same conditions. This means, above all, that the patient must assume the same position on the radiation table during each treatment session.
Individual positioning aid
To ensure the same position, an individual positioning aid is used at the very start of the therapy. This is generally a mattress that adapts to the form of the patient’s body thanks to a vacuum, so that an impression can be made. The lying position on the mattress is determined by the position required for the radiotherapy and, above all, what is most comfortable for the patient. The procedure is as follows: The mattress adapts to the shape of the body. A vacuum is applied to the mattress so that it becomes hard and retains an impression of the body. The patient always lies in this specially formed mould when receiving their daily radiotherapy treatment. This guarantees that their body is always in the same position during each round of therapy.
Calculation of the radiation plan
With the help of this mould, a (CT) scan is then performed on the area which will subsequently receive the computed tomography treatment. This CT scan makes it possible to accurately plan the radiotherapy. On each of the various CT images, the doctor indicates which regions are to be treated with radiotherapy, as well as which areas are to receive the lowest possible dosage. Using this information, the physicist and his team can then exactly calculate the radiation plan. The area to be treated is generally divided into several fields. The linear accelerator is set up so that it directs the radiotherapy at the tumour region from several different directions. In the radiation plan, the size of the fields and the position of the shields are calculated according to the specifications of the tumour’.