Dosimetric properties of a proton beamline dedicated to the treatment of ocular disease

Abstract

Measurements show the proton eyeline meets the requirements to effectively treat ocular disease.

Technical Note: Dosimetric characteristics of the ocular beam line and commissioning data for an ocular proton therapy planning system at the Proton Therapy Center Houston

“…Commissioning a small-field proton beam line is a complex undertaking, as has been described in numerous studies. [1][2][3][4][5][6][7][8][9][10][11] One of the main problems with small proton fields is the difficulty in providing equilibrium conditions for measurement devices that have finite sizes and exhibit artifacts when operated in nonequilibrium conditions. In many small-field beam line configurations, especially when the beams are collimated, electronic equilibrium is not given and interpreting results from measurements becomes difficult.…”

Optimization of a general‐purpose, actively scanned proton beamline for ocular treatments: Geant4 simulations

“…This simulation study shows that the general‐purpose proton beamline existing at CNAO, although optimized to try to meet the requirements for ocular treatments, would be able to deliver small fields at shallow depths with a lateral penumbra much wider than the one (1–2 mm as 80%–20% penumbra) achieved by most beamlines specifically dedicated to eye treatments (4) . This seems to represent a severe limitation for very small tumors (a few millimeters) or lesions very close to critical structures, while its impact on the clinical outcome for less demanding scenarios needs to be further investigated.…”

“…Good results have been obtained in Italy at the INFN (Istituto Nazionale di Fisica Nucleare) Laboratori Nazionali del Sud, within the “CATANA proton therapy” project, where more than 200 patients have been treated since 2002 (3) . Several other experiences in eye proton radiotherapy have already been implemented worldwide, mostly using a dedicated beamline, rather than a large‐field and general‐purpose one (4) . For example, in Europe, at Paul Scherrer Institute (Switzerland), since 1984 more than 4,700 patients were treated within the OPTIS Program (Proton therapy for tumors of the eye) (5) .…”

“…In the clinical practice of eye proton therapy, the currently worldwide accepted technique for dose delivery is represented by the passive scattering modality, (19,20) while the treatment plans are usually calculated using the EYEPLAN software, developed in 1983 by Goitein and Miller (21) and subsequently adapted by Sheen (Douglas Cyclotron, Clatterige Center for Oncology, UK). Low‐energy cyclotrons (62–72 MeV) or high‐energy (up to approximately 250 MeV) cyclotrons or synchrotrons can be used (4) . A planning study with carbon ions has been also reported for eye treatment at NIRS, Japan, using an in‐house treatment planning software: NIRS‐EYEPLAN.…”

Effect of elemental compositions on Monte Carlo dose calculations in proton therapy of eye tumors

“…Despite the widespread use of ocular proton therapy with different suggested methods and designed systems, related literature has reported the dose calculations carried out with the water-equivalent phantoms with non-115 anatomically accurate geometries [22,[31][32][33][34]. Due to the importance of an accurate dose calculation to have a more realistic assessment of sufficiency of the available proton beam for a sensitive organ like the eye, this commonly used approach may make the dosimetry study unreliable.…”