Application of radiation

Because the radiation passes through normal tissue to reach the effected area the side effects must be limited. To ensure this a CT scan is done which is then transferred to a dedicated Treatment Planning System (TPS). On the TPS a 3D image of the treatment area is created using the CT slices. The oncologist delineates the area of interest (tumor) on this 3D image. MRI images where soft tissue tumours are better shown can also be used in conjunction with CT images. The 3D image is used to plan the treatment with multiple field combinations with different angles and energies, to ensure that the dose to the normal tissue and sensitive organs is limited while an optimal dose to the tumor is achieved. The combined dose of the fields where they intersect give the optimal dose required. The different tissue densities, the beam is traveling through, is also taken into account since they have different absorption properties.

To limit the dose to critical organs and normal tissue in the beam path, shielding is used to shape the radiation beam. Modern technology allows for this to be done easily with multi leaf collimators (MLC) instead of lead shielding blocks which are time consuming and labour intensive. To achieve optimum treatment planning, highly skilled and experienced planning radiographers, physicists and a specialized TPS is essential.

To ensure that the treatment is being given correctly, recording and verification systems are essential. This will prevent treatment being given unless all parameters are set-up correctly. The system also records treatment data for future reference. Anatomical verification is also required to ensure that the correct treatment position is used. This is done with a portal imager or the use of verification films.

Simulation and marking of the area

The area to be irradiated is determined by means of a localising scan or X-rays, and then marked. This is called a simulation.

PLEASE BRING ALONG ANY PREVIOUS X-RAYS OR SCANS that may be of use. Sometimes the treatment area is decreased during the course of the treatments. This is called a booster.

It is very important that the marks that have been made on your body remain there.


  • It is very important for you to visit the oncologist once a week during irradiation.
  • Please arrange these appointments with the oncologist's receptionist in good time once you have received the irradiation dates.
  • Please get your irradiation file from the radiotherapists on the day on which you are to visit the oncologist.
  • Please be so kind as to return your file to the radiotherapists after your appointment with the oncologist.
  • When simulation / booster is done, please bring along all your scans and X-rays so that the position of the irradiation area can be determined.
  • To change radiotherapy appointments, please phone the relevant radiotherapy receptionist without delay.

YOU MAY BATH OR SHOWER, but you must make sure that these marks are not washed off. A quick bath or shower is preferable. If you do take a bath, do not soak in the water. Use a gentle soap for example Dove soap.

Irradiation is not painful and patients are not radioactive after irradiation, therefore you pose no threat to other people.

During irradiation you will be alone in the treatment room, but you will be monitored on a television screen. There is also an intercom system.

It is extremely important that you keep very still, but you may breathe normally.

Dr Alberts, Bouwer & Jordaan Inc.

The Alberts, Bouwer & Jordaan practices and clinics are spread across Gauteng and the North West Province and offer the most advanced treatment methods available worldwide. We pride ourselves in our quality and the standard of care given by our doctors, nurses and support staff who treat all our patients with professionalism, compassion and understanding, providing the most effective treatments and therapy.

After hours contact details:

Radiotel: +27 (0)12 333-6000

(for all practices except Klerksdorp)

PO Box 12555, Hatfield, 0028

Download documents:

Manual in terms of section 51 PAIA ACT [1]
Manual in terms of section 51 PAIA ABJ [2]