Investigation of irregular radiation field-based proton therapy using conformal dose layer stacking method

Dose modulation is a key factor in practical proton therapy. thisstudy investigates the dose modulation methodology of irregular radiationfield (irf)-based proton therapy using forward radiation treatment planningand conformal dose layer stacking (cdls) methods. materials and methods:the geometric configuration of a virtual multi-leaf system was constructed togenerate irfs during monte carlo simulations. two patient geometries—lymphatic metastasis and brain tumors—were configured to investigate thedosimetric feasibility and applications of irf-based proton therapy in idealpatient anatomies. the investigated tumors were divided into slicesperpendicular to proton beam axis. segments were designed to be conformalto the profiles of these tumor slices. conformal dose layers were produced bymodulating the proton intensities and energies of the predesigned segments.then, these dose layers were stacked throughout the tumors to obtainsufficient and conformal tumor doses. results: from the proposed irf-basedproton therapy, tumors with 4-7 cm extents along the depth direction couldbe treated with fewer than 10 segments. the lymphatic metastasis and braintumors were sufficiently covered by 95% dose lines, while appropriate distaland proximal dose conformities were achieved. the maximum tumor dosesdid not exceed 110%. conclusions: theoretically, the proposed irf-basedproton therapy using forward planning and cdls methods is feasible from theviewpoint of dosimetry. this study can serve as a foundation for futureinvestigations of potential proton therapy methods based on fast conformaldose layer stacking using radiation fields with irregular shapes.