STEREOTACTIC RADIOTHERAPY

This approach differs from SRS in that it delivers the radiation treatment over a number of fractions (also known as fractionated radiosurgery – FSR). This treatment approach is appropriate for tumours that are larger than 3cm, or are very close to important dose critical structures such as the optic chiasm. Since this treatment needs to be given over many days the localising system (usually a headring) which provides the coordinate that it is aimed at has to be reapplied on a planned multiple daily basis. This is typically done via the use of a relocatable dental plate, to which the reference ring can be attached each day. The number of treatments is determined by the size and type of tumour being treated, and proximity to adjacent tissues. Whilst initially this approach could only be given utilising the same approach as for SRS via multiple arcs of treatment, it can now be given as multiple fixed beams using the MMLC, or more recently via Intensity Modulated Radiotherapy (IMRT) in which each fixed field is broken in to multiple segments allowing better dose conformity to the tumour and sparing of normal tissue. This department was the first in the world to treat any patient with stereotactic IMRT. Each treatment typically takes 15-20 minutes, with no acute side effects experienced. Over the course of treatment there can be some mouth discomfort associated with the use of the dental piece, however this settles quickly after treatment is concluded.

COMPLEX MENINGIOMA CASE

This approach was initially applied to intracranial skull base tumours, however with the use of extended coordinate systems such as the Head and Neck Localiser (HNL) tumours/cancers within the Head and Neck region such as chemodectomas, and even early larynx cancers, can now be treated. This approach may now be able to avoid some of the significant side effects associated with wide field radiotherapy.

Body coordinate systems enable stereotactic radiotherapy to be delivered to other tumours or sites in any part of the body/trunk. This can include treatment of small cancers in the lungs, liver or adrenal glands. More recent developments include the use of stereotactic IMRT for the radical treatment of localised prostate carcinomas.