IMRT

Radiotherapy and Oncology 95 (2010) 109–115

Immobilization characteristics: Results Contents lists available at ScienceDirect

Radiotherapy and Oncology

l Intrafraction motion:

j ourna l homepage : www. thegreen j ourna l . com

Mean 3D of 0.58 mm (SD 0.42 mm)

SBRT set up A clinical comparison of patient setup and intra-fraction motion using frame-based radiosurgery versus a frameless image-guided radiosurgery system for intracranial lesions Naren Ramakrishna * , Florin Rosca, Scott Friesen, Evrim Tezcanli, Piotr Zygmanszki, Fred Hacker Department of Radiation Oncology, Brigham and Women’s Hospital and Dana Farber Cancer Institute, Boston, MA, USA

Frame-based invasive head frame

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a b s t r a c t

Article history: Received 12 June 2009 Received in revised form 8 December 2009 Accepted 29 December 2009 Available online 28 January 2010

Background and purpose: A comparison of patient positioning and intra-fraction motion using invasive frame-based radiosurgery with a frameless X-ray image-guided system utilizing a thermoplastic mask for immobilization. Materials and methods: Overall system accuracy was determined using 57 hidden-target tests. Positioning agreement between invasive frame-based setup and image-guided (IG) setup, and intra-fraction displace- ment, was evaluated for 102 frame-based SRS treatments. Pre and post-treatment imaging was also acquired for 7 patients (110 treatments) immobilized with an aquaplast mask receiving fractionated IG treatment. Results: The hidden-target tests demonstrated a mean error magnitude of 0.7 mm (SD = 0.3 mm). For SRS treatments, mean deviation between frame-based and image-guided initial positioning was 1.0 mm (SD = 0.5 mm). Fusion failures were observed among 3 patients resulting in aberrant predicted shifts. The image-guidance system detected frame slippage in one case. The mean intra-fraction shift magnitude observed for the BRW frame was 0.4 mm (SD = 0.3 mm) compared to 0.7 mm (SD = 0.5 mm) for the frac- tionated patients with the mask system. Conclusions: The overall system accuracy is similar to that reported for invasive frame-based SRS. The intra-fraction motion was larger with mask-immobilization, but remains within a range appropriate for stereotactic treatment. These results support clinical implementation of frameless radiosurgery using the Novalis Body Exac-Trac system. ! 2010 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 95 (2010) 109–115

Mean 3D of 0.40 mm (SD 0.30 mm)

Keywords: Frameless

Radiosurgery Image-guided Stereotactic

Radiosurgery has an important role in the treatment of primary brain tumors, metastases, and functional disorders. Effective radi- osurgery treatment minimizes normal tissue injury by employing sharp dose gradients which must be placed accurately at the mar-

infection, and requires pre-medication. Furthermore, the care of patients wearing head frames creates a clinical resource burden on the day of care, requiring dedicated nursing and physician sup- port. Frame-based treatment also requires treatment planning to

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