Evidence map›Paper›PMID 42608881›Full record

ArticleMedical physics2026

Exploratory personalized radiobiological modeling of bystander and immune effects to inform SFRT-SBRT scheduling.

Jiaxin Li, Fen Wang, Wangyao Li, Chayu Yang, Jufri Setianegara, Shahed Badiyan, Kenneth Westover, Sean Domal, Yuting Lin, Hao Gao

Abstract read
In one paragraph

Article in Medical physics, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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2 · The registry

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4 · The record

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5 · Who and what money

Authors and funding

10 authors.

Jiaxin LiDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Fen WangDepartment of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA.
Wangyao LiDepartment of Radiation Oncology, University of Kansas Medical Center, Kansas City, Kansas, USA.
Chayu YangDepartment of Radiation Oncology, University of Maryland School of Medicine, Baltimore, Maryland, USA.
Jufri SetianegaraDepartment of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Shahed BadiyanDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Kenneth WestoverDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Sean DomalDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Yuting LinDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
Hao GaoDepartment of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.

Funding

Novel Optimization Methods and Treatment Planning System for Clinically-Deliverable Truly-Hybrid Proton-Photon RadiotherapyR37CA250921 · NCI · UT SOUTHWESTERN MEDICAL CENTER · PI Hao Gao · 2021 to 2026
$2.2M
Simultaneous dose and dose rate optimization for clinical FLASH proton radiotherapyR01CA261964 · NCI · UT SOUTHWESTERN MEDICAL CENTER · PI GAO, HAO · 2022 to 2025
$2.0M
The first clinical prototype for proton minibeam radiation therapyR37CA306829 · NCI · UT SOUTHWESTERN MEDICAL CENTER · PI Yuting Lin · 2026 to 2026
$684k
NCI NIH HHS R01 CA261964NCI NIH HHS R01CA261964NCI NIH HHS R37 CA250921NCI NIH HHS R37CA250921NCI NIH HHS R37 CA306829NCI NIH HHS R37CA306829
6 · The paper itself

Abstract

backgroundSpatially fractionated radiation therapy (SFRT) demonstrates clinical efficacy against bulky tumors, but optimal treatment scheduling remains empirical. The technique's heterogeneous dose distribution triggers complex biological effects-including bystander signaling and immune activation-that are not captured by conventional dose-response models. PURPOSE: This study aims to develop a proof-of-concept computational framework to simulate tumor and immune responses during combined Lattice radiotherapy and SBRT) as an initial step toward patient-specific modeling.

methodsA four-compartment ordinary differential equation (ODE) model was established to simulate tumor and lymphocyte dynamics, integrating Gompertz tumor growth kinetics, direct radiation-induced cell killing, and indirect biological effects mediated by intercellular signaling and immune activation. Bystander signaling was described by reaction-diffusion equations modeling spatial propagation from high- to low-dose regions. Immune responses were modeled with coupled lymphocyte-tumor equations, with lymphocyte dose exposure estimated using the HEDOS model. Model parameters were derived from literature and fitted to tumor volume and absolute lymphocyte count (ALC) data from four non-small cell lung cancer (NSCLC) patients treated with SFRT and SBRT.

resultsThe model demonstrated feasibility in reproducing tumor volume (normalized root-mean-square error [NRMSE]: 0.071-0.197) and ALC dynamics (NRMSE: 0.017-0.385). Simulations revealed substantial inter-patient heterogeneity in the estimated contributions of direct radiation and immune-mediated effects, with immune-mediated killing exceeding direct radiation in 2 patients. Combined SFRT-SBRT achieved superior tumor control over either modality alone in our simulations. Notably, the optimal SFRT-SBRT interval appeared patient-specific: extending the interval to 2 months improved outcomes in some patients, while others showed limited benefit, depending on the balance between treatment-induced cell kill and tumor regrowth.

conclusionsWe developed a radiobiological model that simulates tumor and lymphocyte dynamics under combined SFRT-SBRT regimens, providing a preliminary framework for exploring personalized SFRT-SBRT scheduling. These findings warrant further prospective validation in larger patient cohorts before clinical translation.

Indexed as

Bystander EffectDose Fractionation, RadiationModels, BiologicalPrecision MedicineRadiobiologyRadiosurgeryCarcinoma, Non-Small-Cell LungHumansLung NeoplasmsLymphocytesbystander effectimmune responseradiobiological modelspatially fractionated radiation therapy

Identifiers

PMID42608881
PMCPMC13482003

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.