ESTRO 2024 - Abstract Book

S920

Clinical - CNS

ESTRO 2024

Our transitional shifts are well within the institutional tolerance limit set for ET and PTV margin with 95% of confidence level. No inter-correlation between the lateral, vertical & longitudinal shifts attribute that the shifts found are random in nature. Wherever the shifts were found to be beyond our acceptable tolerance limit same were applied and reimaged for validation. ExacTrac helps us in delivering reliable, acceptable and accurate and precise SRS treatment.

Keywords: Stereotactic Radiosurgery, Exactrac, vlidation

References:

1. Erminia I. Estimation of patient setup uncertainty using BrainLAB Exatrac X-Ray 6D system in image-guided radiotherapy. Journ Appl Clin Med Phys 2015; 16 (2): 99-107

2. Van Herk M. Errors and margins in radiotherapy. Semin Radiat Oncol. 2004; 14(1): 52 – 64.

3. Benjamin CL. Monitoring frequency of intra-fraction patient motion using the ExacTrac system for LINAC-based SRS treatments. Journ Appl Clin Med Phys 2018; 19 (3) 58-63

2559

Digital Poster

Outcomes of intracranial germ cell tumours treated at a single UK proton centre

Love Goyal 1 , Anna France 2 , Rovel Colaco 1 , Simona Gaito 1 , Shermaine Pan 1 , Daniel Saunders 1 , Nicola Thorp 1 , Gillian Whitfield 1 1 The Christie NHS Foundation Trust, Proton Beam Therapy, Manchester, United Kingdom. 2 The Christie NHS Foundation Trust, Proton Clinical Outcomes Unit, Manchester, United Kingdom

Purpose/Objective:

Intracranial germ cell tumours are rare brain tumours that occur in children and young adults. There are two main groups, germinomas and non-germinomatous germ cell tumours (NGGCT). Treatment involves mainly chemotherapy and radiotherapy. Surgery, where feasible, is used for NGGCT with residual disease at the end of chemotherapy. Two major European trials, SIOP GCT 96 and SIOP GCT II, looked to improve treatments (1). After closure of SIOP GCT II, the UK Children's Cancer and Leukaemia Group (CCLG) initially recommended following the standard arms of the SIOP GCT II trial. In April 2021, the CCLG further recommended i) that for localised unifocal germinoma in complete radiological response after chemotherapy, the boost should be omitted, ii) that for localised NGGCT, due to an excess of ventricular relapses, whole ventricular radiotherapy (WVRT) at germinoma doses should be added to the focal primary site(s) radiotherapy, and iii) that for high risk NGGCT with AFP>1000, dose intensified chemotherapy could be used at clinician’s discretion (well tolerated but evidence remained insufficient) (2,3,4). The