Radiotherapy

Brachytherapy essentially treats cancer from the inside.

Brachytherapy has proven to be a successful treatment for cancers of the cervix, endometrium, prostate and other types of cancers. Brachytherapy treats cancer by placing radioactive sources directly into or next to the area requiring treatment. This enables clinicians to deliver a high dose with minimal impact on surrounding healthy tissues.

Brachytherapy primarily uses two different techniques:

• Low Dose Rate (LDR) uses a lower strength radioactive source and is associated with longer treatment times (for the one time treatment).
• High Dose Rate (HDR) uses a higher strength radioactive source contained within an afterloader device. The computer driven afterloader delivers the source for a brief period of time to catheters, needles or other appliances placed in the tumour site. HDR is much shorter procedure (minutes vs. days) than LDR but it does require multiple treatments. Increasingly more common, HDR techniques have replaced LDR techniques for most body sites.

With any radiotherapy technique, the goal is the same: to conform the dose to the size and shape of the target while limiting side effects by sparing the surrounding healthy anatomy. In brachytherapy, radiation falls off very rapidly from the target area, easily accomplishing this objective.

Stereotactic radiosurgery (SRS) is a non-invasive, treatment that uses radiation beams to accurately target to treat functional abnormalities and small tumours of the brain with a single high dose of radiation. SRS is not a surgical procedure and does not require an incision or anaesthesia. The radiation is administered by two to three RapidArc radiation beams. This allows radio-surgeons to target the tumour without affecting delicate structures or surrounding healthy tissues. SRS is performed as an outpatient session.

Stereotactic radiosurgery is effective for treating tumours in small areas in the head and neck that cannot be reached by surgery.

When SRS is used to treat body tumours, it’s called stereotactic body radiotherapy (SBRT).

Indication for SRS treatment

Brain/neurological conditions, including:

• Artero-venous malformations, meningiomas, acoustic neuromas, pituitary tumours
• Brain metastases, malignant gliomas, functional conditions 

Stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy, administers very high doses of radiation using several beams of various intensities aimed at different angles to precisely target the tumour.

Stereotactic body radiation treatments are usually given as a single dose or up to five doses once a day, although this can vary depending on the type and location of the tumour and the patient’s physical condition. This procedure is chosen for patients with small, well-defined tumours who cannot tolerate surgery. For some patients, SBRT may be able to replace surgery as a primary cancer treatment.

Indications for SBRT treatment

Extracranial conditions and other malignant and benign tumours (lung, liver, spine etc).

A skin reaction may occur depending on the type of radiotherapy (location, volume, single dose and total dose). With radiotherapy targeting a tumour in the mouth or throat region, or with breast cancer treatment, the skin is relatively severely affected. After two to three weeks of treatment, patients may experience a skin reaction similar to sunburn. Patients experiencing such symptoms should contact the nursing staff who will coordinate further treatment with the doctor. Household remedies should not be used without prior consultation with the doctor. Many common skincare lotions and creams contain traces of heavy metals. The use of such creams causes the radiation to be scattered into the surface of the skin and leads to even higher skin exposure.

With radiotherapy of the throat and thorax areas (e.g. for lung or oesophageal cancer), parts of the mucous membranes of the mouth, throat and oesophagus are often treated simultaneously. These membranes develop an inflammation which may begin to manifest itself in the second or third week of radiotherapy. Any inflammation causes redness, swelling and particularly pain, which mainly affect the patient while eating. In case such symptoms occur, the patient should notify the nursing staff. The nursing staff will coordinate further treatment and care, for example the prescription of a painkiller, with the doctor.

With radiotherapy in the stomach, abdomen and pelvic areas, side effects often include diarrhoea. Treatment of the rectum often causes increased urge to defecate (however, without the actual defecation). Such symptoms are also caused by inflammation in the treated intestinal area as a result of the radiotherapy. Occasionally, patients who receive radiation targeting the intestinal area may feel slightly nauseous an hour or two after treatment. This frequently occurs at the start of a radiotherapy course during the first sessions and is also known as “radiation hangover”. Such symptoms mostly disappear after one to two weeks of treatment and can be easily treated with medication. Such symptoms should also be discussed with the team.

In general, the severity of the side effects varies from individual to individual and depends on the volume and type of radiotherapy. Each person reacts slightly differently to the treatments and unfortunately it is impossible to predict which side effects might actually occur. Any unsual effects should be discussed with radiotherapy team.

The planning computer depicts the tumour as a three-dimensional volume, which then serves as the basis for the radiation plan created by the medical physicist. Mostly, the tumour volume will be “attacked” from various directions within defined safety margins, ensuring that the risk organs are omitted from the field arrangements, if possible. These fields are no longer rectangular, but are instead adapted using shielding in accordance with the defined radiation volume. The aim of any radio-oncological treatment is to subject the tumour region to the highest possible radiation dose while simultaneously protecting the risk organs to the greatest possible extent. The probability of being able to sterilise a tumour depends on its size and histology, as well as particularly on the radiation dose applied. However, the likelihood of suffering side effects depends on the exposure of normal, healthy tissue to radiation. In recent years it has become possible to control and modulate the intensity of the flow of photons within the field (intensity modulated radiotherapy, IMRT). As a result, the high-dose area can be better adapted to the defined tumour field and risk organs can be protected. 

The more precise the treatment is, the less side effects are caused All these new technologies require the radiotherapy treatment to be carried out under exactly the same conditions. The geometry of the linear accelerator is fixed and the dose calculation is based on the assumption that the conditions are always exactly the same as those depicted in the planning computer tomography. If this deviates from the actual situation, the tumour region may be targeted with an insufficient dose, or a risk organ may be exposed to too much irradiation. If the position of the patient deviates by just one to two centimetres from the position originally planned, the radiation will also be “off-target” by this distance. This inaccuracy must be considered and included in the treatment concept. During planning, a safety margin around the tumour volume is calculated in order to ensure the most extensive radiation possible during all fractions. The disadvantage of this approach is a significant increase of the radiation volume, along with the corresponding side effects. The more precisely a radiation therapy can be performed, the smaller this required safety margin is and the smaller the treatment volume becomes. We use advance laser system to align the patient on the daily radiotherapy setup to maintain accuracy. With our modern technology used by expert team, we treat tumour with smallest possible margin and yet achieve accuracy within few millimeters.

In addition to the positioning aids described, it is now possible to check the accuracy of the patient’s position and particularly improve it with the help of a positioning control system. Two short radioscopies can be performed in different directions before the radiotherapy begins. These images show the current position of the patient and are then compared with a digital reconstruction of the planning CT. The images of the current radioscopy and the planning CT images are merged, so any deviations between the current radiation position and the originally planned position can directly be determined.

Some targets like the breast are likely to move with breathing. This may spill undesirable radiation into healthy lung and heart. With our advance 4-dimensional motion management system, radiation is safely steered away from these sensitive organs and yet successfully treat the target.

Prostate cancer requires a very high dose of radiotherapy to achieve cure. However, back passage (rectum) is closely related to prostate and is likely to receive a significant dose of radiation with associated side effects. We are the only centre where we can insert a gel (short outpatient procedure) to displace rectum away from prostate prior to radiotherapy. This technique is proven to reduce the radiotherapy side effects.