Organ-specific equivalent uniform dose constraints and radiobiological parameters for radiation treatment planning of abdominal tumors. J Appl Clin Med Phys 2026 Jan;27(1):e70401
Date
12/29/2025Pubmed ID
41456609Pubmed Central ID
PMC12744925DOI
10.1002/acm2.70401Scopus ID
2-s2.0-105026223945 (requires institutional sign-in at Scopus site)Abstract
BACKGROUND: Radiation therapy planning (RTP) for abdominal tumors often requires multiple dose-volume constraints for each organ at risk (OAR), which vary with different fractionation schemes. This variability can complicate biologically optimized treatment planning.
PURPOSE: This study aims to extract fractionation-independent dose constraints based on the concept of equivalent uniform dose (EUD), utilizing published clinical data for a range of fractionation regimens. The goal is to derive organ-specific radiobiological parameters as well as the EUD for each OAR that can be used in biologically optimized treatment planning for abdominal tumors, independent of the specific fractionation scheme applied.
METHODS: Clinical dose-volume constraints for duodenum, stomach, and small bowel were compiled from available literature sources. These dose constraints were obtained for conventionally fractionated radiotherapy (CFRT), hypofractionated RT, and stereotactic body radiotherapy (SBRT) and were associated with less than a 10% risk of grade 3 toxicity as categorized by CTCAE v.3 or v.4, RTOG, and EORTC. For each OAR, an iso-EUD fitting with EUD calculated based on the linear-quadratic (LQ) model or linear-quadratic-linear (LQ-L) model and a dose volume histogram generated from these dose volume constraints for each fractionation was applied to extract model parameters such as α/β ratio and 'n' (the volume effect of the OAR). Based on the obtained parameters, the dose constraint in EUD and the equivalent physical dose in 2Gy fraction (EQD2) were calculated.
RESULTS: The EUD constraints for LQ-L (LQ) models are 52.62 (55.10) Gy, 48.22 (48.60) Gy, and 46.10 (45.06) Gy, α/β values are 5.42 (5.59) Gy, 7.67 (6.76) Gy, and 12.15 (8.20) Gy, and 'n' values are 0.06 (0.01), 0.03 (0.02), and 0.06 (0.08) for duodenum, small bowel, and stomach, respectively. Additional two parameters for the three OARs in LQ-L are 5.15 Gy, 8.65 Gy, and 5.20 Gy for dt and 5.40, 4.72, and 3.33 for γ/α. The LQ-L model fits the clinical data better than the LQ model.
CONCLUSIONS: The obtained α/β values are comparable with those published previously. The extracted EUD constraints together with the volume effect parameter 'n' can be used for plan optimization and evaluation.
Author List
Dabaghmanesh S, Li XA, Paulson ES, Erickson B, Hall W, Tai AAuthors
Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of WisconsinWilliam Adrian Hall MD Chair, Professor in the Radiation Oncology department at Medical College of Wisconsin
Eric Paulson PhD Chief, Professor in the Radiation Oncology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Abdominal NeoplasmsHumans
Intestine, Small
Organs at Risk
Radiobiology
Radiosurgery
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Radiotherapy, Intensity-Modulated
