Biology And Medicine Radiology And Nuclear Medicine

Image-Guided Stereotactic Radiosurgery Using a Specially Designed High-Dose-Rate Linac

Authors: Bayouth, John E. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)]. E-mail: john-bayouth@uiowa.edu Kaiser, Heather S. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)] Smith, Mark C. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)] Pennington, Edward C. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)] Anderson, Kathleen M. C. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)] Ryken, Timothy C. [Department of Neurosurgery, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)] Buatti, John M. [Department of Radiation Oncology, Holden Comprehensive Cancer Center, University of Iowa Hospitals and Clinics, Iowa City, IA (United States)]
 
Abstract: Stereotactic radiosurgery and image-guided radiotherapy (IGRT) place enhanced demands on treatment delivery machines. In this study, we describe a high-dose-rate output accelerator as a part of our stereotactic IGRT delivery system. The linac is a Siemens Oncor without a flattening filter, and enables dose rates to reach 1000 monitor units (MUs) per minute. Even at this high-dose-rate, the linac dosimetry system remains robust; constancy, linearity, and beam energy remain within 1% for 3 to 1000 MU. Dose profiles for larger field sizes are not flat, but they are radially symmetric and, as such, able to be modeled by a treatment planning system. Target localization is performed via optical guidance utilizing a 3-dimensional (3D) ultrasound probe coupled to an array of 4 infrared light-emitting diodes. These diodes are identified by a fixed infrared camera system that determines diode position and, by extension, all objects imaged in the room coordinate system. This system provides sub-millimeter localization accuracy for cranial applications and better than 1.5 mm for extracranial applications. Because stereotactic IGRT can require significantly longer times for treatment delivery, the advantages of the high-dose-rate design and its direct impact on IGRT are discussed.
Publication Date: 01 Jul 2007
Resource Type: Journal Article
Resource Relation: Journal: Medical Dosimetry; Journal Volume: 32; Journal Issue: 2; Other Information: DOI: 10.1016/j.meddos.2007.01.010; PII: S0958-3947(07)00032-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input
Country of Publication: United States
Language: English
Keywords relating to this report:
ACCURACY
CAMERAS
DOSE RATES
DOSIMETRY
IMAGES
LIGHT EMITTING DIODES
LINEAR ACCELERATORS
RADIATION DOSES
RADIOTHERAPY
SURGERY