STEREOTACTIC RADIATION TREATMENT IN AUSTRALIA

The Stereotactic Radiosurgery Unit in this hospital setting in Australia began patient treatment in Sydney in 1990, making this unit most experienced medical service in Australasia with over 700 patients treated by stereotactic radiosurgery to date. In addition fractionated stereotactic radiotherapy has been available for the past 5 years with in excess of 300 patients treated within this time frame. In 1998 a Radionics Mini Multileaf Collimator (MMLC) was acquired and integrated onto a Siemens MD2 Linear Accelerator. The MMLC was subsequently transferred to a Siemens PRIMUS Accelerator in 2000 with and expansion of the stereotactic program. In November 2000 this department became the first site in Australia to offer Intensity Modulated Radiation Therapy (IMRT). With these facilities the first person in the world to receive IMRT stereotactically with the MMLC was treated in November 2000. This treatment has been done using a Siemens PRIMUS Linear Accelerator, with SIMTEC, PRIMEVIEW, PRIMELINK, and Radionics MMLC. Advanced computer programs are available and combine with our Quality Assurance Programs to ensure accuracy and safety of treatment delivery.

Many lesions or tumours in the brain are not suitable for treatment by surgery. Features that determine this include: the site, including proximity to important brain structures such as optic chiasm, brain stem, previous treatment given, and patient preference for non surgical treatment. Stereotactic radiation treatment relies upon precisely locating the lesion in the brain with exact coordinates (as with latitude and longitude), and aiming at this target. This treatment can be given as follows:-

Stereotactic Radiosurgery - a single high dose of radiation is given, the procedure being done in one day, the great majority being treated as outpatients. This is suitable for vascular malformations, benign tumours (eg acoustic neuromas) and cancer metastases, where the target (lesion) is less than 3cm in size, and away from important structures such as visual (optic) nerves.

Stereotactic Radiotherapy - this gives the radiation treatment over many days (fractions) ranging from 3-5, to 28-30, being treated 5 days per week. This procedure allows larger lesions (up to 5cm in size) and those close to important structures to be treated.