Ion radiotherapy with protons or carbon ions is one of the most advanced clinical methods for cancer treatment. To further improve the local tumor control, ion radiotherapy using multiple ion species has been investigated. Due to complexity of dose distributions delivered by multi-ion therapy in a tumor, a validation strategy for the planned treatment efficacy must be established that can be potentially used in the quality assurance (QA) protocol for the multi-ion treatment plans. In previous work, we demonstrated that the microdosimetric approach using the silicon on insulator (SOI) microdosimeter is practical for validating cell surviving fraction (SF) of MIA PaCa-2 cells in the independent fields of helium, carbon, oxygen, and neon ion beams.This paper extends the previous study, and we demonstrate a microdosimetry based approach as a pilot study to build the QA protocol in the multi-ion therapy predicting the cell SF along the spread-out Bragg peak obtained by combined irradiations of He+O and C+Ne ions. Across the study, the SOI microdosimeter system MicroPlus was used for measurement of the lineal energy in individual ion fields followed by deriving the lineal energy of combined ion fields delivered by a pencil beam scanning system at HIMAC.The predicted cell SF based on derived lineal energy and dose in the combined fields was in good agreement with the planned cell SF by our in-house treatment planning system.The presented results indicated the potential benefit of the SOI microdosimeter system MicroPlus as the QA system in the multi-ion radiotherapy.
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http://dx.doi.org/10.1088/1361-6560/ac8968 | DOI Listing |
Phys Med Biol
December 2024
Centre for Medical Radiation Physics, University of Wollongong, Northsfield Ave., Wollongong, New South Wales, 2522, AUSTRALIA.
The recently developed V79-RBEbiological weighting function (BWF) model is a simple and robust tool for a fast relative biological effectiveness (RBE) assessment for comparing different exposure conditions in particle therapy. In this study, the RBEderived by this model (through the Particle and Heavy Ion Transport code System (PHITS) simulated d(y) spectra) is compared with values of RBEusing experimentally derived d(y) spectra from a silicon-on-insulator (SOI) microdosimeter. Approach: Experimentally measured d(y) spectra are used to calculate an RBEvalue utilizing the V79-RBEBWF model as well as the modified microdosimetric kinetic model (MKM) to produce an RBE-vs-ytrend for a wide range of ions.
View Article and Find Full Text PDFPhys Med Biol
November 2024
Department of Accelerator and Medical Physics, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, Chiba, Japan.
Linear energy transfer (LET) verification was conducted using a silicon-on-insulator (SOI) microdosimeter during the commissioning of LET-optimized carbon-ion radiotherapy (CIRT). This advanced treatment technique is expected to improve local control rates, especially in hypoxic tumors.An SOI microdosimeter with a cylindrical sensitive volume of 30m diameter and 5m thickness was used.
View Article and Find Full Text PDFInt J Radiat Oncol Biol Phys
July 2024
Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Phys Med Biol
October 2022
Department of Accelerator and Medical Physics, Institute for Quantum Medical Science, QST, 263-8555 Chiba, Japan.
Ion radiotherapy with protons or carbon ions is one of the most advanced clinical methods for cancer treatment. To further improve the local tumor control, ion radiotherapy using multiple ion species has been investigated. Due to complexity of dose distributions delivered by multi-ion therapy in a tumor, a validation strategy for the planned treatment efficacy must be established that can be potentially used in the quality assurance (QA) protocol for the multi-ion treatment plans.
View Article and Find Full Text PDFPhys Med
October 2021
Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia. Electronic address:
In this study, Monte Carlo codes, Geant4 and MCNP6, were used to characterize the fast neutron therapeutic beam produced at iThemba LABS in South Africa. Experimental and simulation results were compared using the latest generation of Silicon on Insulator (SOI) microdosimeters from the Centre for Medical Radiation Physics (CMRP). Geant4 and MCNP6 were able to successfully model the neutron gantry and simulate the expected neutron energy spectrum produced from the reaction by protons bombarding a Be target.
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