A novel lattice technique via adaptive spot assignment and LET optimization based proton arc therapy.

Authors

Yujia Qian, Yajun Jia, Qingkun Fan, Lewei Zhao, Riao Dao, Tianyang Li, Sheng Zhang, Gang Peng, FangFang Yin, Manju Liu, Xuanfeng Ding, Haibo Lin, Ning Wen, Hao Peng, Yuanyuan Wang, Yifeng Yang, YanHong Zheng, Kunyu Yang, Jing Huang, Zhitao Dai, Hong Quan, Gang Liu

Published in

International journal of radiation oncology, biology, physics. Aug 15, 2026. Epub Aug 15, 2026.

Abstract

Lattice radiation therapy is an innovative three-dimensional implementation of spatially fractionated radiation therapy. This study aimed to develop a novel lattice-based proton arc therapy (PAT) technique to deliver a highly modulated peak-valley spatial dose distribution and a modulated linear energy transfer (LET) distribution.
We introduced a PAT lattice algorithm that optimizes three key components, including energy-layer selection, spot assignment, and LET optimization (PAT_LESL). A simulated annealing algorithm was used to select the optimal energy layers. Meanwhile, an adaptive spot assignment strategy was implemented using a spot-sparsity optimization algorithm based on the primal-dual active set with continuation to achieve an improved peak-to-valley dose ratio (PVDR). Subsequently, LET optimization was achieved using the alternating direction method of multipliers with a minimum monitor unit constraint. Eighteen patients were selected to evaluate plan quality and delivery efficiency compared with the lattice technique based on the previously reported spot-scanning proton arc therapy energy sequence optimization algorithm (PAT_seq). Feasibility and dosimetric accuracy were further validated using clinical phantom measurements.
Compared with PAT_seq, the PAT_LESL plan exhibited improved dose and LET distributions with higher delivery efficiency. More specifically, PAT_LESL achieved steeper dose gradients, improving the PVDR from 16.90 ± 18.04 to 41.85 ± 29.69 (p < 0.01), shortening the beam delivery time by 37.43%, and increasing the target spot coverage by 44.12% while reducing the spot number by 93.78%. It also increased the mean LET in the LTV from 2.84 ± 0.38 to 3.59 ± 0.26 keV/μm (p < 0.01), on average. Meanwhile, the phantom measurement confirmed high agreement between the planned and delivered results.
A novel PAT lattice technique using adaptive spot assignment and LET optimization could deliver an enhanced peak-valley spatial dose distribution. Experimental validation on a clinical proton system confirmed deliverability and dosimetric accuracy, which may facilitate future clinical translation of proton lattice radiotherapy.

PMID:
42603564
Bibliographic data and abstract were imported from PubMed on 16 Aug 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.