What to expect in breast radiation therapy planning

The thought of planning your breast radiation therapy can be extremely daunting, anticipating an unknown experience involving your body. Dr Duvern Ramiah explains step-by-step what will be done in the planning and set-up process to set your mind at ease and allow you to be confident in knowing exactly what you’ll undergo.

Breast radiation therapy for breast cancer can consist of up to 35 daily radiation sessions. It is important to ensure that radiation therapy is delivered accurately, in the precise way that the oncologist has planned, for each session. This is to ensure that the high doses of radiation are given to the area where the oncologist intended, such as the breast, chest wall and lymph glands; the organs close by, such as the heart and lungs, are avoided as much as possible.

To treat the breast, chest wall and lymph glands, several adjacent radiation treatment fields or portals are needed. They’re angled in different directions to avoid the underlying normal tissues, such as the lungs and heart. A small misalignment or change in treatment position between the treatments can cause radiation beam misalignments or the incorrect areas receiving radiation.

Hence, it is imperative that the patient is in exactly the same position each day.

In order to ensure this, prior to starting the daily radiation therapy, the oncologist schedules a day for radiation planning or simulation. During this session, patients are asked to disrobe up to the waist.   The patient is then positioned into the treatment position, which normally involves lying on an immobilisation device (see photo).

The treatment position is usually lying on the back (supine position), although, more rarely, a position on   the tummy (prone) or on the side (decubitus) positions are used. The arm, on the involved side, is usually raised above the head to avoid it being in the path of the radiation. The positioning device usually has an armrest or handle to hold onto, to make keeping the arm above the head a little easier. Sometimes patients may experience initial difficulty in raising the arm into position for radiation therapy due to recent axillary surgery, but with exercise and physiotherapy, this can be corrected very quickly.

Once in the intended treatment position, the radiotherapist will make several marks on the chest wall. These marks are initially made in pen, and at the end of the session some marks, usually between one and five, may be made permanent by tattooing. The treatment position is well documented using laser triangulation and these tattoo marks. These tattoos serve as reference points when aligning the patients before each radiation treatment. They assist with attaining the same treatment position on each day. The tattoos are usually the size of  a pinpoint or freckle, and although they’re permanent, they are very small, so not very noticeable.

The tattoos make it possible to bathe or shower every day without worrying about removing them. Also, if any additional radiation therapy is needed in the future, they serve as a permanent record of previous treatments.

During the tattooing process, the area to be tattooed is first cleaned with an alcohol swab. A drop of India ink is placed over the area. The skin is then punctured with a small needle, to allow the ink under the skin creating the tattoo.

Once the patient is put into the radiation treatment position, a CT scan is done in this position. This scan will then be reviewed by the radiation oncologist and they contour or draw on the areas to receive radiation.

The radiation oncologist, together with the team of radiotherapists and physicists, will work out the best way of getting the radiation into the treatment areas, and avoid the normal structures. Once this is done, the treatment plan is approved, and the patient typically starts treatment within a few days.

Another way the radiation treatment is checked that it is being given in the correct area is in the form of X-rays. Several X-rays will be done as verifications of the radiation treatment fields. Your radiation oncologist will review these X-rays.

Written by Dr Duvern Ramiah.

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