• Eman Eldebawy, William Parker, Wamied Abdel Rahman, and Carolyn R Freeman.
• Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec, Canada.
• Int. J. Radiat. Oncol. Biol. Phys. 2012 Mar 1; 82 (3): e501-5.

PurposeTo determine the best treatment technique for patients with retinoblastoma requiring radiotherapy to the whole eye.Methods And MaterialsTreatment plans for 3 patients with retinoblastoma were developed using 10 radiotherapy techniques including electron beams, photon beam wedge pair (WP), photon beam three-dimensional conformal radiotherapy (3D-CRT), fixed gantry intensity-modulated radiotherapy (IMRT), photon volumetric arc therapy (VMAT), fractionated stereotactic radiotherapy, and helical tomotherapy (HT). Dose-volume analyses were carried out for each technique.ResultsAll techniques provided similar target coverage; conformity was highest for VMAT, nine-field (9F) IMRT, and HT (conformity index [CI] = 1.3) and lowest for the WP and two electron techniques (CI = 1.8). The electron techniques had the highest planning target volume dose gradient (131% of maximum dose received [D(max)]), and the CRT techniques had the lowest (103% D(max)) gradient. The volume receiving at least 20 Gy (V(20Gy)) for the ipsilateral bony orbit was lowest for the VMAT and HT techniques (56%) and highest for the CRT techniques (90%). Generally, the electron beam techniques were superior in terms of brain sparing and delivered approximately one-third of the integral dose of the photon techniques.ConclusionsInverse planned image-guided radiotherapy delivered using HT or VMAT gives better conformity index, improved orbital bone and brain sparing, and a lower integral dose than other techniques.Copyright © 2012 Elsevier Inc. All rights reserved.

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