Initial Experience with Volumetric IMRT (RapidArc) for Intracranial Stereotactic Radiosurgery
Received 6 July 2009; received in revised form 6 October 2009; accepted 7 October 2009. published online 08 March 2010. Corrected Proof
Purpose
Initial experience with delivering frameless stereotactic radiotherapy (SRT) using volumetric intensity-modulated radiation therapy (IMRT) delivered with RapidArc is presented.
Methods and Materials
Treatment details for 12 patients (14 targets) with a mean clinical target volume (CTV) of 12.8 ± 4.0 cm3 were examined. Dosimetric indices for conformality, homogeneity, and dose gradient were calculated and compared with published results for other frameless, intracranial SRT techniques, including CyberKnife, TomoTherapy, and static-beam IMRT. Statistics on setup and treatment times and per patient dose validations were examined.
Results
Dose indices compared favorably with other techniques. Mean conformality, gradient, and homogeneity index values were 1.10 ± 0.11, 64.9 ± 14.1, 1.083 ± 0.026, respectively. Median treatment times were 4.8 ± 1.7 min.
Conclusion
SRT using volumetric IMRT is a viable alternative to other techniques and enables short treatment times. This is anticipated to have a positive impact on radiobiological effect and for facilitating wider use of SRT.
∗Department of Radiation Oncology, Department of Surgery, University of Massachusetts Medical School, Worcester, MA
†Division of Neurosurgery, Department of Surgery, University of Massachusetts Medical School, Worcester, MA
Reprint requests to: Charles S. Mayo, Ph.D., Department of Radiation Oncology, HB200, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655. Tel: (744) 442-5560; Fax: (774) 442-5006
Conflicts of interest: The first author, has research grant support from Varian Medical Systems.
ABSTRACT