Possible fractionated regimens for image-guided intensity-modulated radiation therapy of large arteriovenous malformations.
The aim of this study was to estimate a plausible alpha/beta ratio for arteriovenous malformations (AVMs) based on reported clinical data, and to design possible fractionation regimens suitable for image-guided intensity-modulated radiation therapy (IG-IMRT) for large AVMs based on the newly obtained alpha/beta ratio. The commonly used obliteration rate (OR) for AVMs with a three year angiographic follow-up from many institutes was fitted to linear-quadratic (LQ) formalism and the Poisson OR model. The determined parameters were then used to calculate possible fractionation regimens for IG-IMRT based on the concept of a biologically effective dose (BED) and an equivalent uniform dose (EUD). The radiobiological analysis yields a alpha/beta ratio of 2.2 +/- 1.6 Gy for AVMs. Three sets of possible fractionated schemes were designed to achieve equal or better biological effectiveness than the single-fraction treatments while maintaining the same probability of normal brain complications. A plausible alpha/beta ratio was derived for AVMs and possible fractionation regimens that may be suitable for IG-IMRT for large AVM treatment are proposed. The sensitivity of parameters on the calculation was also studied. The information may be useful to design new clinical trials that use IG-IMRT for the treatment of large AVMs.
Qi
X Sharon
XS
Department of Radiation Oncology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. xqi@radonc.mcw.edu
Schultz
Christopher J
CJ
Li
X Allen
XA
D019583:Dose Fractionation, Radiation; D005240:Feasibility Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000000981:diagnostic imaging* / Q000601:surgery*; D011859:Radiography; D016634:Radiosurgery / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*