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ORIGINAL RESEARCH article
Front. Oncol.
Sec. Cancer Imaging and Image-directed Interventions
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1591139
Feasibility study for proton dose calculation of esophageal squamous cell carcinoma based on stopping power ratio directly derived from dual energy CT
Provisionally accepted
Miaomiao Li 1
Yongbin Cui 2 Xinjun Lin 2
Yuan Yuan Yan 3 Qianyu Liu 2 Mingming Nie 4 Wenzhen Gong Ye 4 Yong Huang 3 Jinhu Chen 2*
Yong Yin 2*- 1 Shandong University Cancer Center, Shandong University, Jinan, China
- 2 Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China
- 3 Department of Radiology, Shandong Cancer Hospital, Jinan, China
- 4 Clinical Science，Philips Healthcare, Beijing, China
Purpose: To investigate the feasibility of proton therapy planning using stopping power ratio (SPR) maps directly generated from spectral CT raw data, and to perform a comparative evaluation of dose calculation uncertainties between SPR maps derived from conventional CT Hounsfield Unit (HU) conversion and direct spectral CT SPR generation.Materials and Methods: A retrospective analysis was conducted on 30 patients with mid-thoracic esophageal squamous cell carcinoma (ESCC) who underwent pre-treatment spectral CT imaging. Target volumes and organs at risk (OARs) were delineated on contrast-enhanced CT images and subsequently registered to both non-contrast CT and SPR maps. Three treatment plans were generated: Intensity-modulated radiotherapy (IMRT) plan based on conventional CT，Intensity-modulated proton therapy (IMPT) plan using HU-SPR conversion，IMPT plan utilizing direct SPR maps (IMPT-SPR) from spectral CT. Dose-volume parameters for target volumes and OARs (lungs, heart, spinal cord) were systematically analyzed. Comparative dosimetric analyses were performed among the three plans and between paired groups.Results: All plans met clinical radiotherapy requirements. For OARs (lungs, heart), IMPT plans demonstrated significantly lower dose-volume parameters compared to IMRT, except for maximum dose (Dmax). Between the two IMPT approaches, no statistically significant differences were observed in dose-volume parameters (p>0.05), except for the gradient index which was significantly higher in the HU-converted IMPT plan (p<0.05). No significant differences were detected in heart, lung and spinal cord dosimetric parameters between IMPT approaches.Conclusion: IMPT demonstrated superior OAR sparing compared to IMRT. For mid thoracic ESCC patients under proton therapy, dose calculations based on CT-HU conversion was showed comparable dosimetric impact to DECT-derived SPR in terms of target coverage and OAR protection. These findings support the clinical feasibility of conventional CT-based proton therapy planning and dose calculation.
Keywords: Dual-energy CT, Proton therapy, photon therapy, Stopping power ratio, esophageal squamous cell carcinoma
Received: 10 Mar 2025; Accepted: 02 Apr 2025.
Copyright: © 2025 Li, Cui, Lin, Yan, Liu, Nie, Gong Ye, Huang, Chen and Yin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Jinhu Chen, Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China
Yong Yin, Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, China
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