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. 2024 Apr 21:11:100001.
doi: 10.1016/j.ijpt.2024.01.001. eCollection 2024 Mar.

Real-Time Gated Proton Therapy: Commissioning and Clinical Workflow for the Hitachi System

Hao Chen  1 , Emile Gogineni  1   2 , Yilin Cao  1   3 , John Wong  1 , Curtiland Deville  1 , Heng Li  1
Affiliations

Real-Time Gated Proton Therapy: Commissioning and Clinical Workflow for the Hitachi System

Hao Chen et al. Int J Part Ther. .

Abstract

Purpose: To describe the commissioning of real-time gated proton therapy (RGPT) and the establishment of an appropriate clinical workflow for the treatment of patients.

Materials and methods: Hitachi PROBEAT provides pencil beam scanning proton therapy with an advanced onboard imaging system including real-time fluoroscopy. RGPT utilizes a matching score to provide instantaneous system performance feedback and quality control for patient safety. The CIRS Dynamic System combined with a Thorax Phantom or plastic water was utilized to mimic target motion. The OCTAVIUS was utilized to measure end-to-end dosimetric accuracy for a moving target across a range of simulated situations. Using this dosimetric data, the gating threshold was carefully evaluated and selected based on the intended treatment sites and planning techniques. An image-guidance workflow was developed and applied to patient treatment.

Results: Dosimetric data demonstrated that proton plan delivery uncertainty could be within 2 mm for a moving target. The dose delivery to a moving target could pass 3%/3 mm gamma analysis following the commissioning process and application of the clinical workflow detailed in this manuscript. A clinical workflow was established and successfully applied to patient treatment utilizing RGPT. Prostate cancer patients with implanted platinum fiducial markers were treated with RGPT. Their target motion and gating signal data were available for intrafraction motion analysis.

Conclusion: Real-time gated proton therapy with the Hitachi System has been fully investigated and commissioned for clinical application. RGPT can provide advanced and reliable real-time image guidance to enhance patient safety and inform important treatment planning parameters, such as planning target volume margins and uncertainty parameters for robust plan optimization. RGPT improved the treatment of patients with prostate cancer in situations where intrafraction motion is more than defined tolerance.

Keywords: Image-guided proton therapy; Intrafractional motion management; Motion management for IMPT; Proton therapy for prostate cancer; Real-time gated proton therapy.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
RGPT control signaling, as it relates to (1) the proton beam phase of the synchrotron (“SYN BM”), (2) the RGPT gating signal (“RGPT Gate”), and (3) the beam current gating at isocenter (“Beam on Gate”). Abbreviation: RGPT, real-time gated proton therapy.
Figure 2
Figure 2
(A) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (real-time gated proton therapy [RGPT]) with ±1 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (B) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±1.5 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (C) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at cross-zero position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (D) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at summit position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (E) The top left: dosimetry measurement (RGPT) while ±2 cm motion in 6 seconds while the reference at summit position. The bottom left: dosimetry measurement without RGPT. The top right: profile comparison in the motion direction. The bottom right: gamma analysis.
Figure 2
Figure 2
(A) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (real-time gated proton therapy [RGPT]) with ±1 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (B) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±1.5 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (C) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at cross-zero position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (D) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at summit position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (E) The top left: dosimetry measurement (RGPT) while ±2 cm motion in 6 seconds while the reference at summit position. The bottom left: dosimetry measurement without RGPT. The top right: profile comparison in the motion direction. The bottom right: gamma analysis.
Figure 2
Figure 2
(A) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (real-time gated proton therapy [RGPT]) with ±1 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (B) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±1.5 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (C) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at cross-zero position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (D) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at summit position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (E) The top left: dosimetry measurement (RGPT) while ±2 cm motion in 6 seconds while the reference at summit position. The bottom left: dosimetry measurement without RGPT. The top right: profile comparison in the motion direction. The bottom right: gamma analysis.
Figure 2
Figure 2
(A) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (real-time gated proton therapy [RGPT]) with ±1 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (B) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±1.5 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (C) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at cross-zero position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (D) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at summit position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (E) The top left: dosimetry measurement (RGPT) while ±2 cm motion in 6 seconds while the reference at summit position. The bottom left: dosimetry measurement without RGPT. The top right: profile comparison in the motion direction. The bottom right: gamma analysis.
Figure 2
Figure 2
(A) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (real-time gated proton therapy [RGPT]) with ±1 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (B) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±1.5 cm motion in 6 seconds while the reference at cross-zero position. The top right: profile comparison in motion direction. The bottom right: gamma analysis. (C) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at cross-zero position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (D) The top left: dosimetry measurement without motion. The bottom left: dosimetry measurement (RGPT) with ±2 cm motion in 6 seconds cycle while the reference is at summit position. The top right: profile comparison in the motion direction. The bottom right: gamma analysis. (E) The top left: dosimetry measurement (RGPT) while ±2 cm motion in 6 seconds while the reference at summit position. The bottom left: dosimetry measurement without RGPT. The top right: profile comparison in the motion direction. The bottom right: gamma analysis.
Figure 3
Figure 3
Matching score related to water equivalent thickness in X-ray direction. Abbreviation: RGPT, real-time gated proton therapy.
Figure 4
Figure 4
(A) DRR for field at 90-degree. (B) DRR for field at 270-degree. (C) Selected Fiducial marker contour for RGPT with 2 mm tolerance. Abbreviations: DRR, digitally reconstructed radiograph; RGPT, real-time gated proton therapy.
Figure 5
Figure 5
(A) Fiducial marker motion (<0.5 mm) and gating signal during field delivery. (B) Fiducial marker motion (<1 mm) and gating signal during field delivery. (C) Real-time gated proton therapy turns off the beam when fiducial marker moves out of tolerance.
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