Teletherapy is radiation, which is focused on an area of interest from a distance. The radiation passes through normal tissues to reach the area to be treated to high dose. The radiation dose is reduced on the normal tissues by using multiple fields and shielding blocks.
 

The planning process involves:

When planning Radical radiation the area of interest is determined by scanning, this is usually done on a CT scanner. This can be done with or without a MRI scan, which can be matched to the CT scan on modern three-dimensional treatment planning systems. It allows compensation for different tissue densities in planning therapy as different tissues have different absorption properties which in turn effects the dose delivered in depth.

We make extensive use of specialised immobilisation artefacts, (which ensure accuracy in daily treatment), protective artefacts, (which reduces dose to normal tissues, thereby reducing potential side effects) and tissue compensating artefacts (which ensure more even dose distributions).

All treatment plans are done with the input of the radiation oncologists, radiation therapists and medical radiation physicists ensuring that the treatment is planned in accordance with the original intention and that the highest possible dose is delivered to the tumour area and the lowest possible dose to surrounding normal tissues. All planning is done in accordance with international prescribing and dose determination norms.

The treatment process involves:

The daily delivery of treatment on state of the art linear accelerators by the therapy radiographers. Treatment can range from as few as one to as many as 35 treatments. The daily usage of record and verify systems, which in effect prevent treatment being given unless all parameters are set up correctly; it also keeps a log of treatments as given.

The routine use of verification films on treatment to ensure correct set up and treatment. The protocol for this varies by anatomical site and is not the same for all sites. These are usually done prior to the initiation of radiation and at set intervals thereafter according to set protocols to identify and correct any treatment variations which may occur due to any internal or external movement between treatments.

All units also have in-vivo dosimetry systems and all treatment doses given are checked at the start-up and at regular intervals to ensure correct dose of treatment is delivered – these are also done according to set protocols.  Doses to sensitive structures can also be measured in this fashion.

Radiotherapy equipment:

 GVI Oncology utilizes state of the art equipment in all its units, which enables it to deliver the highest quality treatment in all of its units.  GVI Oncology has its own in house service engineers to ensure optimum treatment availability of all equipment.  GVI Oncology also has a structured equipment maintenance and replacement schedule ensuring that all facilities maintain state of the art services.

GVI Oncology has state of the art digital Siemens Linear accelerators which are multi-energy (photons and electrons) treatment units giving maximum flexibility in deciding on optimal patient treatment.  It generates both low (6MV) and high-energy (15MV) photon beams and a range of electrons (4 to 18MeV), enabling us to deliver optimum doses of radiation to both superficial and deeper-seated tumours. Multi Leaf Collimators, Cone beam CT and Electronic Portal Imaging provide for fast and accurate delivery of the radiation to these tumours.

The Record and Verify Systems are sophisticated computer systems used to record all treatments and check the correct set-up of the treatment units prior to each treatment.  It prohibits treatment unless all set-parameters are correct to ensure patients peace of mind at all times.

We use CMS Xio Treatment Planning systems which are all fully three-dimensional treatment-planning computers to plan the treatments.  It allows one to plan maximum radiation to the tumour site, whilst also minimizing exposure to normal tissues around the tumour.  These planning systems are linked to CT, MRI and PET imaging facilities to provide for accurate delineation of target sites through the highest quality diagnostic imaging available.  GVI Oncology has a well established centralized planning centre to ensure the highest quality and standard of planning for all patients throughout the organization by having all plans done by hightly skilled and experienced planning radiographers. 

For Stereotactic radiosurgery we use the Brainlab planning software together with the Moduleaf micro multileaf collimator to deliver extremely accurate radiation to cranial lesions at our Vincent Pallotti unit in Cape Town.  Here we also have access to a Multi source afterloading system and 3-D planning computer for delivering remote afterloading Brachytherapy.

GVI is also one of the leaders in Prostate brachytherapy and has been involved with this procedure since 2003.