Dose Verification in Lung Radiotherapy Using PET Imaging of Nanoparticle-Induced Positrons

Document Type : Original Paper

Authors

1 Department of Medical Physics, Medical School, Tabriz University of Medical Sciences, Tabriz, Iran.

2 Department of Medical Physics, Hamadan University of Medical Sciences, Hamadan, Iran

3 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran

10.22038/ijmp.2026.92153.2636

Abstract

Introduction: Accurate verification of radiation dose delivery remains a major challenge in radiotherapy. Positron emission tomography (PET) imaging of megavoltage (MV)-induced positrons (MVIPET) has recently emerged as a potential in vivo dosimetry technique. In this study, we investigated the feasibility of enhancing MVIPET signals using high-Z nanoparticles (NPs), specifically platinum (Pt) and silver (Ag), to enable real-time dose monitoring during lung radiotherapy.
Material and Methods: PET images arising from positrons induced by platinum and silver nanoparticles in a lung tumor were generated during radiotherapy with 6, 10, and 15 MV photon beams using the GATE Monte Carlo code. The resulting images were evaluated for both image quality and dose verification.
Results: Results showed that positron production, absorbed dose, and PET signal intensity increased with both photon beam energy and NP concentration, with PtNPs producing significantly higher enhancement than AgNPs. High-quality MVIPET images with acceptable SBR and CNR, and low RMSE, were obtained for PtNP concentrations ≥8 wt% at 10 MV and ≥4 wt% at 15 MV. In contrast, AgNPs required higher concentrations and only yielded reliable monitoring at 15 MV. At 6 MV, image quality and dose–image correlation were insufficient for clinical feasibility.
Conclusion: These findings demonstrate that MVIPET, particularly when combined with PtNPs and higher photon energies, is a promising strategy for real-time, non-invasive dose verification in lung radiotherapy.

Keywords

Main Subjects

References

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Iranian Journal of Medical Physics
Volume 22, Issue 6 - Serial Number 6
November and December 2025
Pages 369-376

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History

  • Receive Date: 21 October 2025
  • Revise Date: 30 December 2025
  • Accept Date: 05 February 2026

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