Page 40 - HA Convention 2016 [Abstracts (Day 2)]

HOSPITAL AUTHORITY CONVENTION 2016 Masterclasses

M11.1 Advance in Neurosurgical Treatment Using LINAC Machine 09:00 Room 221

Linear Accelerator-based Stereotactic Radiosurgery — Evolution and Revolution
Yam KY
Department of Neurosurgery, Tuen Mun Hospital, Hong Kong

The Hospital Authority introduced Stereotactic Radiosurgery for the treatment of intracranial pathologies in the mid 1990s.
Stereotactic radiosurgery is a highly complicated treatment modality requiring cooperation and collaboration from radiation
oncologist, medical physicist, neurosurgeon and radiographer. The term “stereotactic” means accurate localisation of the
structures of the brain in three dimensions. For radiosurgery, it is defined as the utilisation of a highly conformal externally
generated ionizing radiation to inactivate or eradicate lesions or targets inside or around the brain without the need for a
surgical incision.

In early days, we relied on the use of stereotactic skull frame to provide an accurate array of brain structures. We obtained
diagnostic images like CT or cerebral angiogram after placement of stereotactic skull frame and localiser onto patient’s skull.
The skull frame will be in place for hours until we have finished all the procedures, which include lesion localisation, treatment
planning, dose prescription, quality assurance and the radiosurgery treatment. With the advancement of technologies and
computer science, we continue to produce treatment plans with improved lesion coverage, better conformity and enhanced
preservation of normal brain structure and its function. However, the development of Image Guided Radiation Therapy (IGRT)
has revolutionised the work flow and patient care pathway of stereotactic radiosurgery. This technology allows us to obtain
frequent imaging during a course of radiation therapy for the purpose of improving accuracy and precision of dose delivery.
With IGRT, patients can be handled in a frameless manner, making stereotactic radiosurgery a completely non-invasive
ambulatory procedure.

This presentation will give a brief description of the journey we have gone through and touch on future development of
stereotactic radiosurgery.

M11.2 Advance in Neurosurgical Treatment Using LINAC Machine 09:00 Room 221

Wednesday, 4 May Image-guidance Intracranial Stereotactic Radiosurgery — the Local Perspective
Kam MKM
Department of Clinical Oncology, Prince of Wales Hospital, Hong Kong

Stereotactic Radiosurgery plays an important role in the management of many benign and malignant brain lesions. It is a
precision therapy making use of ionizing radiation to ablate intracranial lesions without the need of undergoing open surgery.

First pioneered by Swedish neurosurgeon Professor Lars Leksell, radiosurgery was first defined as “a single high dose
fraction of radiation, stereotactically directed to an intracranial region of interest”. Using a frame-based immobilisation
system, radiosurgery has been used to treat a wide variety of intracranial diseases such as brain metastases, acoustic
neuroma, meningioma, pituitary tumor, trigeminal neuralgia, and arterio-venous malformation.

Technological improvements on medical imaging and computing in recent years have much expanded the clinical utility
of stereotactic radiosurgery. Image guidance technology using online or real-time stereoscopic X-rays or CT scanning
enables the evolution from an invasive frame-based system to a completely user-friendly frameless system while still
maintaining the same degree of targeting accuracy. The rid of frame immobilisation also allows the use of more fractions
in the treatment of a target that is too large or too close to critical organs for single fraction radiosurgery treatment. Today,
stereotactic radiosurgery or stereotactic hypofractionated radiotherapy has been employed to treat both intracranial as well
as extracranial diseases.

In this presentation, the common indications of intracranial radiosurgery will be covered. Technical concerns, treatment
planning details, expected outcome, and potential complications of treating brain metastases, arteriovenous malformation,
meningioma, and acoustic neuroma will be discussed, and local data from a single institute will be presented.

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