Conventional radiotherapy typically damages significant amounts of normal, healthy tissue. Therefore, it is unsuitable to be used on patients whose tumour is close to critical structures, such as the brain and spinal cord.
There are several stereotactic radiosurgical techniques available that allow for more precise targeting in these situations. However, before the inception of the CyberKnife®, these systems could only be used for the brain and required the fitting of an invasive frame to the patient's skull.
It creates new potential for non-invasive, high precision, targeted radiotherapy. The CyberKnife® is different because it is a whole-body, image-guided, stereotactic radiosurgery system. It is mounted on a robotic arm which means that it is much more flexible and can therefore be used on tumours anywhere in the body, not just the head. Also, the CyberKnife® does not use a head frame so it is much more comfortable for the patient.
By firing fine beams of x-rays from multiple angles focused on the tumour, the CyberKnife® causes significantly less damage than conventional radiotherapy. It also has sub-millimetre accuracy which, of course, is vital for tumours that are adjacent to critical structures.
In addition, the CyberKnife® technology has the power to accurately target moving tumours, such as lung cancers, which shift with the breathing of the patient. By inserting markers around the cancer, the image-guided robotic arm can keep directing the radiation at the tumour, leaving surrounding tissue unharmed.
Multi-sliced computed tomography
This technique has very high resolution, which is obviously very important when doctors are looking for early diagnosis. It is also very fast, allowing doctors to pick up tumours like hepatomas, which were difficult to diagnose with older machines because hepatomas take up the contrast agents so quickly
A look at the statistics to back up the statement above: the multi-slice CT system has a resolution of 0.4 mm and a speed of 0.33 seconds per 64-slice rotation, with a scan time of just 8 seconds and a patient throughput time of 10 minutes.
As a result, the potential for multi-slice CT goes beyond oncology. It can, for example, be used instead of coronary angiography in some patients (bypassing the need for catheterization), and for ‘virtual colonoscopy' (without having to insert an endoscope).
Mammography with stereotactic biopsy
Breast biopsy via mammogram has long been considered an uncomfortable and unpleasant experience. Firstly, positioning the breast onto the equipment before biopsy typically requires the patient to assume an unnatural and painful position; secondly, the patient can see the biopsy needle enter the breast, which is often a frightening experience, particularly when a large needle is used.
WIMC has invested in a new system that dramatically reduces these disadvantages.
The stereotactic breast biopsy at WIMC is called the Advanced Breast Biopsy Instrument (ABBI) procedure. In addition, the ABBI system may be able to excise small in situ or invasive breast cancers. This device removes a larger core of tissue (5-20mm). In this fashion, the entire lesion can be removed which can sometimes provide a more accurate diagnosis. This stereotactic breast biopsy is performed under local anasthesia. Patients will only have minimal discomfort during or after the procedure and usually resume normal activities by the following day.
Because it is mounted on a ring, the plates onto which the breast is mounted can be tilted through three dimensions for optimal patient comfort.
Furthermore, in the new system, the biopsy can be taken in the prone position, with the breast facing downwards and obscured from the patient's view.
PET/CT scanner
This technique combines both PET and CT scans which provide functional and anatomical data, respectively. Combining the two scans enables doctors to get complete information on the location, size, nature and extent of disease. PET/CT is also non-invasive, easy to perform and reproducible.
It is also a very versatile technique and can, for example, be used to monitor the progress of on-going chemotherapy and to detect relapse at a very early stage. It is possible that
PET/CT will help in cancer management.
LINAC with Intensity Modulated Radiotherapy (IMRT)
WIMC has also been involved in the introduction of intensity modulated radiation therapy (IMRT) in Malaysia which is an advanced mode of high precision radiation therapy made possible by the fully computerized delivery controls of the SIEMENS ONCOR. In IMRT the intensity of the beam is modulated by the linac to produce far better conformality of the high dose to the target, producing a sharper dose gradient outside the target so that dose to critical structures is minimal.
Cyclotron
PET/CT uses a radioactive form of glucose for imaging purposes. But because tumours tend to absorb more glucose, they show up as ‘hot spots'. However, production of the radio-pharmaceutical used in this technique: 2-[fluorine-18]-fluoro-2-deoxy-D-glucose ( FDG) – has been a major stumbling block in the quest to bring PET/CT scanning to Malaysia.
A sophisticated piece of equipment, known as a Cyclotron, is required to make FDG. Since FDG has a half-life of only 110 minutes, importing FDG from overseas is not an option.
