A GPU-based finite-size pencil beam algorithm with 3D-density correction for radiotherapy dose calculation

TL;DR

This paper presents a GPU-accelerated finite-size pencil beam algorithm with 3D-density correction that significantly improves dose calculation accuracy for radiotherapy while maintaining near real-time performance, suitable for online adaptive treatment planning.

Contribution

The authors developed a GPU-based FSPB algorithm with 3D-density correction, enhancing accuracy over previous models while retaining high computational efficiency for clinical use.

Findings

Improved dosimetric accuracy with 3D-density correction over conventional FSPB.

Dose calculation for IMRT plans achieved within 1 second on GPU.

Slight reduction in efficiency (~5-15%) compared to previous GPU FSPB, with significant accuracy gains.

Abstract

Targeting at the development of an accurate and efficient dose calculation engine for online adaptive radiotherapy, we have implemented a finite size pencil beam (FSPB) algorithm with a 3D-density correction method on GPU. This new GPU-based dose engine is built on our previously published ultrafast FSPB computational framework [Gu et al. Phys. Med. Biol. 54 6287-97, 2009]. Dosimetric evaluations against Monte Carlo dose calculations are conducted on 10 IMRT treatment plans (5 head-and-neck cases and 5 lung cases). For all cases, there is improvement with the 3D-density correction over the conventional FSPB algorithm and for most cases the improvement is significant. Regarding the efficiency, because of the appropriate arrangement of memory access and the usage of GPU intrinsic functions, the dose calculation for an IMRT plan can be accomplished well within 1 second (except for one case) with this new GPU-based FSPB algorithm. Compared to the previous GPU-based FSPB algorithm without 3D-density correction, this new algorithm, though slightly sacrificing the computational efficiency (~5-15% lower), has significantly improved the dose calculation accuracy, making it more suitable for online IMRT replanning.