Proton arc therapy reduces the dose delivered to circulating blood compared to intensity-modulated proton therapy for head-and-neck cancer.
- 1Division of Life Sciences, TRIUMF, Vancouver, British Columbia, Canada.
- 2Department of Radiation Oncology, William Beaumont University Hospital, Corewell Health, Royal Oak, Michigan, USA.
Abstract
Background
Compared to intensity-modulated proton therapy (IMPT), proton arc therapy (PAT) has various dosimetric advantages. However, questions have been raised over whether the larger low-dose bath during PAT may increase radiation-induced lymphocyte killing, which is correlated with adverse clinical outcomes.Purpose
The purpose of this study is to quantitatively compare radiation dose delivery to circulating blood during IMPT and PAT.Methods
For each of 10 head-and-neck cancer patients, one IMPT and one PAT treatment plan were created, and the hematological dose (HEDOS) blood dose model was used to simulate radiation dose delivery to circulating blood. HEDOS simulations utilized gantry angle-wise dose distributions (including for PAT) and considered gantry rotation and energy layer switching as well as irradiation times. Blood dose histograms as well as the mean dose to all simulation blood particles (Dmean) and the dose delivered to the 90% and 10% of blood particles receiving the highest dose (D90% and D10%) were then compared between IMPT and PAT.Results
For IMPT, blood dose metrics (in the form of mean over all patients ± one standard deviation) were (0.522 ± 0.204)Gy(RBE) for D90%, (0.563 ± 0.212)Gy(RBE) for Dmean, and (0.605 ± 0.219)Gy(RBE) for D10%. For PAT, D90% was (0.430 ± 0.184)Gy(RBE), Dmean was (0.483 ± 0.195)Gy(RBE), and D10% was (0.538 ± 0.207)Gy(RBE). The Wilcoxon signed-rank test indicated statistically significant (p < 0.05) differences between blood dose metrics of IMPT and PAT for all patients, and IMPT did not increase the percentage of blood particles which received no radiation dose during the delivery of a single treatment fraction.Conclusions
Compared to IMPT, proton arc therapy was associated with significantly lower radiation dose delivery to circulating blood across a variety of different metrics. Proton arc therapy for head-and-neck cancer is therefore not expected to result in higher radiation-induced killing of circulating lymphocytes compared to IMPT.
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BibTeX
@article{tattenberg2026proton,
title = {{Proton arc therapy reduces the dose delivered to circulating blood compared to intensity-modulated proton therapy for head-and-neck cancer.}},
author = {Sebastian Tattenberg and Peilin Liu and Xiaoda Cong and Cornelia Hoehr and Xuanfeng Ding},
journal = {Journal of applied clinical medical physics},
year = {2026},
month = oct,
doi = {10.1002/acm2.70864},
url = {https://europepmc.org/article/MED/42900560},
note = {CC BY},
}
RIS
TY - JOUR
TI - Proton arc therapy reduces the dose delivered to circulating blood compared to intensity-modulated proton therapy for head-and-neck cancer.
AU - Sebastian Tattenberg
AU - Peilin Liu
AU - Xiaoda Cong
AU - Cornelia Hoehr
AU - Xuanfeng Ding
PY - 2026
DA - 2026/10/30
JO - Journal of applied clinical medical physics
DO - 10.1002/acm2.70864
UR - https://europepmc.org/article/MED/42900560
AB - Background Compared to intensity-modulated proton therapy (IMPT), proton arc therapy (PAT) has various dosimetric advantages. However, questions have been raised over whether the larger low-dose bath during PAT may increase radiation-induced lymphocyte killing, which is correlated with adverse clinical outcomes.Purpose The purpose of this study is to quantitatively compare radiation dose delivery to circulating blood during IMPT and PAT.Methods For each of 10 head-and-neck cancer patients, one IMPT and one PAT treatment plan were created, and the hematological dose (HEDOS) blood dose model was used to simulate radiation dose delivery to circulating blood. HEDOS simulations utilized gantry angle-wise dose distributions (including for PAT) and considered gantry rotation and energy layer switching as well as irradiation times. Blood dose histograms as well as the mean dose to all simulation blood particles (Dmean) and the dose delivered to the 90% and 10% of blood particles receiving the highest dose (D90% and D10%) were then compared between IMPT and PAT.Results For IMPT, blood dose metrics (in the form of mean over all patients ± one standard deviation) were (0.522 ± 0.204)Gy(RBE) for D90%, (0.563 ± 0.212)Gy(RBE) for Dmean, and (0.605 ± 0.219)Gy(RBE) for D10%. For PAT, D90% was (0.430 ± 0.184)Gy(RBE), Dmean was (0.483 ± 0.195)Gy(RBE), and D10% was (0.538 ± 0.207)Gy(RBE). The Wilcoxon signed-rank test indicated statistically significant (p < 0.05) differences between blood dose metrics of IMPT and PAT for all patients, and IMPT did not increase the percentage of blood particles which received no radiation dose during the delivery of a single treatment fraction.Conclusions Compared to IMPT, proton arc therapy was associated with significantly lower radiation dose delivery to circulating blood across a variety of different metrics. Proton arc therapy for head-and-neck cancer is therefore not expected to result in higher radiation-induced killing of circulating lymphocytes compared to IMPT.
SN - 1526-9914
ER -