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Parisi A, Beltran CJ, Furutani KM. Variable RBE in proton radiotherapy: a comparative study with the predictive Mayo Clinic Florida microdosimetric kinetic model and phenomenological models of cell survival. Phys Med Biol 2023; 68:185020. [PMID: 38133518 DOI: 10.1088/1361-6560/acf43b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/25/2023] [Indexed: 12/23/2023]
Abstract
Objectives. (1) To examine to what extent the cell- and exposure- specific information neglected in the phenomenological proton relative biological effectiveness (RBE) models could influence the computed RBE in proton therapy. (2) To explore similarities and differences in the formalism and the results between the linear energy transfer (LET)-based phenomenological proton RBE models and the microdosimetry-based Mayo Clinic Florida microdosimetric kinetic model (MCF MKM). (3) To investigate how the relationship between the RBE and the dose-mean proton LET is affected by the proton energy spectrum and the secondary fragments.Approach. We systematically compared six selected phenomenological proton RBE models with the MCF MKM in track-segment simulations, monoenergetic proton beams in a water phantom, and two spread-out Bragg peaks. A representative comparison within vitrodata for human glioblastoma cells (U87 cell line) is also included.Main results. Marked differences were observed between the results of the phenomenological proton RBE models, as reported in previous studies. The dispersion of these models' results was found to be comparable to the spread in the MCF MKM results obtained by varying the cell-specific parameters neglected in the phenomenological models. Furthermore, while single cell-specific correlation between RBE and the dose-mean proton LET seems reasonable above 2 keVμm-1, caution is necessary at lower LET values due to the relevant contribution of secondary fragments. The comparison within vitrodata demonstrates comparable agreement between the MCF MKM predictions and the results of the phenomenological models.Significance. The study highlights the importance of considering cell-specific characteristics and detailed radiation quality information for accurate RBE calculations in proton therapy. Furthermore, these results provide confidence in the use of the MCF MKM for clonogenic survival RBE calculations in proton therapy, offering a more mechanistic approach compared to phenomenological models.
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Affiliation(s)
- Alessio Parisi
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, United States of America
| | - Chris J Beltran
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, United States of America
| | - Keith M Furutani
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, United States of America
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Kong X, Wang Y, Huang J, Zhang W, Du C, Yin Y, Xue H, Gao H, Liu K, Wu T, Sun L. Microdosimetric assessment about proton spread-out Bragg peak at different depths based on the normal human mesh-type cell population model. Phys Med Biol 2023; 68:175010. [PMID: 37578025 DOI: 10.1088/1361-6560/acec2b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 07/31/2023] [Indexed: 08/15/2023]
Abstract
Objective.In clinical proton therapy, the spread-out Bragg peak (SOBP) is commonly used to fit the target shape. Dose depositions at microscopic sites vary, even with a consistent absorbed dose (D) in SOBP. In the present study, monolayer mesh-type cell population models were developed for microdosimetric assessment at different SOBP depths.Approach.Normal human bronchial epithelial (BEAS-2B) and hepatocytes (L-O2) mesh-type cell models were constructed based on fluorescence tomography images of normal human cells. Particle transport simulation in cell populations was performed coupled with Monte Carlo software PHITS. The relationship between microdosimetry and macrodosimetry of SOBP at different depths was described by analyzing the microdosimetric indicators such as specific energyz,specific energy distributionfz,D,and relative standard deviationσz/z¯within cells. Additionally, the microdosimetric distributions characteristics and their contributing factors were also discussed.Main results.The microscopic dose distribution is strongly influenced by cellular size, shape, and material. The mean specific energyz¯of nucleus and cytoplasm in the cell population is greater than the overall absorbed dose of the cell population model (Dp), with a maximumz¯/Dpof 1.1. The cellular dose distribution is different between the BEAS-2B mesh-type model and its concentric ellipsoid geometry-type model, which difference inz¯is about 10.3% for the nucleus and about 7.5% for the cytoplasm with the SOBP depth of 15 cm. WhenD= 2 Gy, the maximumzof L-O2 nucleus reaches 2.8 Gy andσz/z¯is 5.1% at the mid-depth SOBP (16-18 cm); while the maximumzof the BEAS-2B nucleus reaches 2.2 Gy with only 2.7% ofσz/z¯.Significance.The significant variation of microdosimetric distributions of SOBP different depths indicates the necessity to use mesh-type cell population models, which have the potential to be compared with biological results and build the bio-physical model.
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Affiliation(s)
- Xianghui Kong
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Yidi Wang
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Jiachen Huang
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Wenyue Zhang
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Chuansheng Du
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Yuchen Yin
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Huiyuan Xue
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Han Gao
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Kun Liu
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Tao Wu
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
| | - Liang Sun
- State Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, People's Republic of China
- School of Radiation Medicine and Protection, Soochow University, Suzhou 215123, People's Republic of China
- Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Suzhou 215123, People's Republic of China
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DeCunha JM, Newpower M, Mohan R. GPU-accelerated calculation of proton microdosimetric spectra as a function of target size, proton energy, and bounding volume size. Phys Med Biol 2023; 68:165012. [PMID: 37429311 DOI: 10.1088/1361-6560/ace60a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
Objective.Shortcomings of dose-averaged linear energy transfer (LETD), the quantity which is most commonly used to quantify proton relative biological effectiveness, have long been recognized. Microdosimetric spectra may overcome the limitations of LETDbut are extremely computationally demanding to calculate. A systematic library of lineal energy spectra for monoenergetic protons could enable rapid determination of microdosimetric spectra in a clinical environment. The objective of this work was to calculate and validate such a library of lineal energy spectra.Approach. SuperTrack, a GPU-accelerated CUDA/C++ based application, was developed to superimpose tracks calculated using Geant4 onto targets of interest and to compute microdosimetric spectra. Lineal energy spectra of protons with energies from 0.1 to 100 MeV were determined in spherical targets of diameters from 1 nm to 10μm and in bounding voxels with side lengths of 5μm and 3 mm.Main results.Compared to an analogous Geant4-based application, SuperTrack is up to 3500 times more computationally efficient if each track is resampled 1000 times. Dose spectra of lineal energy and dose-mean lineal energy calculated with SuperTrack were consistent with values published in the literature and with comparison to a Geant4 simulation. Using SuperTrack, we developed the largest known library of proton microdosimetric spectra as a function of primary proton energy, target size, and bounding volume size.Significance. SuperTrack greatly increases the computational efficiency of the calculation of microdosimetric spectra. The elevated lineal energy observed in a 3 mm side length bounding volume suggests that lineal energy spectra determined experimentally or computed in small bounding volumes may not be representative of the lineal energy spectra in voxels of a dose calculation grid. The library of lineal energy spectra calculated in this work could be integrated with a treatment planning system for rapid determination of lineal energy spectra in patient geometries.
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Affiliation(s)
- Joseph M DeCunha
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
- Medical Physics Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States of America
| | - Mark Newpower
- University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States of America
| | - Radhe Mohan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
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Magrin G, Palmans H, Stock M, Georg D. State-of-the-art and potential of experimental microdosimetry in ion-beam therapy. Radiother Oncol 2023; 182:109586. [PMID: 36842667 DOI: 10.1016/j.radonc.2023.109586] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/28/2023]
Abstract
In radiotherapy, radiation-quality should be an expression of the biological and physical characteristics of ionizing radiation such as spatial distribution of ionization or energy deposition. Linear energy transfer (LET) and lineal energy (y) are two descriptors used to quantify the radiation quality. These two quantities are connected and exhibit similar features. In ion-beam therapy (IBT), lineal energy can be measured with microdosimeters, which are specifically designed to cope with the high fluence of particles in clinical beams, while the quantification of LET is generally based on calculations. In pre-clinical studies, microdosimetric spectra are used for the indirect determination of relative biological effectiveness (RBE), e.g., using the microdosimetric kinetic model (MKM) or biophysical response functions. In this context it is important to consider saturation effects, which occur when the highest values of y become less biologically relevant compared to the relative contribution they make to the physical dose. Recent clinical data suggests that local tumor control and normal tissue effects can be linked to macroscopic and microscopic dosimetry parameters. In particular, positive clinical outcomes have been correlated to the highest LET values in the density distribution, and there is no evident link to the saturation discussed above. A systematic collection of microdosimetric information in combination with clinical data in retrospective studies may clarify the role of radiation quality at the highest LET. In the clinical setting, microdosimetry is not widely used yet, despite its potential to be linked with LET by experimentally-determined y values. Through this connection, both play an important role in complex therapy techniques such as intensity modulated particle therapy (IMPT), LET-painting and multi-ion optimization. This review summarizes the current state of microdosimetry for IBT and its potential, as well as research and development needed to make experimental microdosimetry a mature procedure in a clinical context.
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Affiliation(s)
- Giulio Magrin
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Hugo Palmans
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria; National Physical Laboratory, Teddington, UK
| | - Markus Stock
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria; Karl Landsteiner Universität, Krems, Austria
| | - Dietmar Georg
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria; Medical University of Vienna, Austria.
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Nabha R, De Saint-Hubert M, Marichal J, Esser J, Van Hoey O, Bäumer C, Verbeek N, Struelens L, Sterpin E, Tabury K, Marek L, Granja C, Timmermann B, Vanhavere F. Biophysical characterization of collimated and uncollimated fields in pencil beam scanning proton therapy. Phys Med Biol 2023; 68. [PMID: 36821866 DOI: 10.1088/1361-6560/acbe8d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/23/2023] [Indexed: 02/25/2023]
Abstract
Objective. The lateral dose fall-off in proton pencil beam scanning (PBS) technique remains the preferred choice for sparing adjacent organs at risk as opposed to the distal edge due to the proton range uncertainties and potentially high relative biological effectiveness. However, because of the substantial spot size along with the scattering in the air and in the patient, the lateral penumbra in PBS can be degraded. Combining PBS with an aperture can result in a sharper dose fall-off, particularly for shallow targets.Approach. The aim of this work was to characterize the radiation fields produced by collimated and uncollimated 100 and 140 MeV proton beams, using Monte Carlo simulations and measurements with a MiniPIX-Timepix detector. The dose and the linear energy transfer (LET) were then coupled with publishedin silicobiophysical models to elucidate the potential biological effects of collimated and uncollimated fields.Main results. Combining an aperture with PBS reduced the absorbed dose in the lateral fall-off and out-of-field by 60%. However, the results also showed that the absolute frequency-averaged LET (LETF) values increased by a maximum of 3.5 keVμm-1in collimated relative to uncollimated fields, while the dose-averaged LET (LETD) increased by a maximum of 7 keVμm-1. Despite the higher LET values produced by collimated fields, the predicted DNA damage yields remained lower, owing to the large dose reduction.Significance. This work demonstrated the dosimetric advantages of combining an aperture with PBS coupled with lower DNA damage induction. A methodology for calculating dose in water derived from measurements with a silicon-based detector was also presented. This work is the first to demonstrate experimentally the increase in LET caused by combining PBS with aperture, and to assess the potential DNA damage which is the initial step in the cascade of events leading to the majority of radiation-induced biological effects.
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Affiliation(s)
- Racell Nabha
- Radiation Protection Dosimetry and Calibration Expert Group, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium.,KU Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, Leuven, Belgium
| | - Marijke De Saint-Hubert
- Radiation Protection Dosimetry and Calibration Expert Group, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | | | - Johannes Esser
- West German Proton Therapy Centre Essen, Essen, Germany.,West German Cancer Center (WTZ), University Hospital Essen, Essen, Germany
| | - Olivier Van Hoey
- Radiation Protection Dosimetry and Calibration Expert Group, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Christian Bäumer
- West German Proton Therapy Centre Essen, Essen, Germany.,West German Cancer Center (WTZ), University Hospital Essen, Essen, Germany.,TU Dortmund University, Department of Physics, Dortmund, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Nico Verbeek
- West German Proton Therapy Centre Essen, Essen, Germany.,West German Cancer Center (WTZ), University Hospital Essen, Essen, Germany
| | - Lara Struelens
- Radiation Protection Dosimetry and Calibration Expert Group, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Edmond Sterpin
- KU Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, Leuven, Belgium.,UCLouvain, Institut de Recherche Expérimentale et Clinique, MIRO Lab, Brussels, Belgium
| | - Kevin Tabury
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | | | | | - Beate Timmermann
- West German Proton Therapy Centre Essen, Essen, Germany.,West German Cancer Center (WTZ), University Hospital Essen, Essen, Germany.,German Cancer Consortium (DKTK), Heidelberg, Germany.,Department of Particle Therapy, University Hospital Essen, Essen, Germany
| | - Filip Vanhavere
- Radiation Protection Dosimetry and Calibration Expert Group, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium.,KU Leuven, Department of Oncology, Laboratory of Experimental Radiotherapy, Leuven, Belgium
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Dawn S, Bakshi A, Sharma R, Ramprasath V. Experimental and Monte Carlo based study of different microdosimetric quantities at mixed radiation environments of nuclear reactor, reprocessing facility and D-D accelerator. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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A novel method to assess the incident angle and the LET of protons using a compact single-layer timepix detector. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2022.110349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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