Image-Guided Decubitus Craniospinal Irradiation Setup in a Fixed-Beam Proton Room: Accuracy and Efficiency.

@article{zeng2026imageguided,
  title = {{Image-Guided Decubitus Craniospinal Irradiation Setup in a Fixed-Beam Proton Room: Accuracy and Efficiency.}},
  author = {Qi Zeng and Zhiqiang Han and Arpit Chhabra and Huifang Zhai and Qing Chen and Andy Shim and Andrew Okhuereigbe and Anh Kha and Jewel Graham and Anya Burke and Meng Wei Ho and Francis Yu and Yao Yu and Yoshiya Yamada and Charles B Simone and Haibo Lin and Dong Han},
  journal = {International journal of particle therapy},
  year = {2026},
  month = aug,
  doi = {10.1016/j.ijpt.2026.101957},
  url = {https://europepmc.org/article/MED/42898231},
  note = {CC BY-NC-ND},
}

TY  - JOUR
TI  - Image-Guided Decubitus Craniospinal Irradiation Setup in a Fixed-Beam Proton Room: Accuracy and Efficiency.
AU  - Qi Zeng
AU  - Zhiqiang Han
AU  - Arpit Chhabra
AU  - Huifang Zhai
AU  - Qing Chen
AU  - Andy Shim
AU  - Andrew Okhuereigbe
AU  - Anh Kha
AU  - Jewel Graham
AU  - Anya Burke
AU  - Meng Wei Ho
AU  - Francis Yu
AU  - Yao Yu
AU  - Yoshiya Yamada
AU  - Charles B Simone
AU  - Haibo Lin
AU  - Dong Han
PY  - 2026
DA  - 2026/08/31
JO  - International journal of particle therapy
DO  - 10.1016/j.ijpt.2026.101957
UR  - https://europepmc.org/article/MED/42898231
AB  - Purpose  Recent developments have further demonstrated the feasibility of craniospinal irradiation (CSI) delivery using simplified beam arrangements, such as a single posterior brain beam. Extending these advances, CSI delivered in the lateral decubitus position within a fixed-beam proton room offers an opportunity to improve room utilization and treatment access but introduces unique challenges in patient setup and image guidance.Methods  This study compares 2 image-guided setup workflows for decubitus CSI to evaluate whether meaningful differences exist. We retrospectively analyzed 10 CSI patients treated in the decubitus position between 2024 and 2025 using the fixed-beam ProBeam system with the 3-iso technique. Two setup workflows were evaluated: (1) Continuous Full-Field Image Guidance (CFF-IG), in which all isocenters were aligned prior to treatment delivery, and (2) Selective Field-Based Image Guidance (SF-IG), in which full-field imaging was applied only at the initial fraction, followed by field-specific verification thereafter. Setup accuracy was quantified using translational and rotational deviations derived from oblique kV imaging, and dosimetric robustness was assessed through target coverage and junction dose gradient analysis. Setup efficiency was evaluated using treatment room time stamps.Results  Across all 3 isocenters, mean translational deviations were below 4 mm and mean angular deviations were below 1.5°. Differences in target coverage (ΔD95) and junction dose gradients were small between the 2 workflows. No statistically significant differences in setup accuracy or dosimetric quality were observed. SF-IG was associated with shorter average setup time, with the majority of treatment sessions completed within 30 minutes.Conclusions  Both CFF-IG and SF-IG achieved setup accuracy within institutional action levels and maintained dosimetric robustness for CSI delivered in the decubitus position using pencil beam scanning. The absence of significant differences suggests that either approach may be clinically feasible for decubitus CSI delivery. SF-IG offers a more time-efficient workflow without compromising treatment quality, supporting its use as the preferred default strategy, while CFF-IG may be reserved for select cases requiring enhanced global realignment. These findings support decubitus CSI as a practical extension of modern single-beam and simplified pencil beam scanning CSI techniques.
SN  - 2331-5180
ER  -