MRI-guided radiotherapy: Opening our eyes to the future

Kishan, Amar U.; Lee, Percy

doi:10.15761/icst.1000181

Cited by 8 publications

(6 citation statements)

References 47 publications

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“…Among several clinical modalities such as 6MV-linac X-ray, proton, carbon ion, and neutron capture therapies [2][3][4][5][6][7], boron neutron capture therapy (BNCT), in which 10 B is administered to tumor cells [8], is one of the most effective approaches for treating malignant tumors. Due to the high linear energy transfer (LET) particles with a short range within approximately 10 µm (i.e., 1.47 MeV α particle and 0.84 MeV 7 Li ion in 94% captures) that are emitted during the 10 B(n,α) 7 Li reaction [9], the thermal neutron irradiation causes substantial damage to cells that take up the tumor-seeking 10 B compounds, actualizing tumor-cell-selective killing. Boron neutron capture therapy has shown to have significant potential for treating cancers such as melanoma, brain tumors, and head and neck cancers.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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A Model for Estimating Dose-Rate Effects on Cell-Killing of Human Melanoma after Boron Neutron Capture Therapy

Matsuya

Fukunaga

Omura

et al. 2020

Cells

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Boron neutron capture therapy (BNCT) is a type of radiation therapy for eradicating tumor cells through a 10B(n,α)7Li reaction in the presence of 10B in cancer cells. When delivering a high absorbed dose to cancer cells using BNCT, both the timeline of 10B concentrations and the relative long dose-delivery time compared to photon therapy must be considered. Changes in radiosensitivity during such a long dose-delivery time can reduce the probability of tumor control; however, such changes have not yet been evaluated. Here, we propose an improved integrated microdosimetric-kinetic model that accounts for changes in microdosimetric quantities and dose rates depending on the 10B concentration and investigate the cell recovery (dose-rate effects) of melanoma during BNCT irradiation. The integrated microdosimetric–kinetic model used in this study considers both sub-lethal damage repair and changes in microdosimetric quantities during irradiation. The model, coupled with the Monte Carlo track structure simulation code of the Particle and Heavy Ion Transport code System, shows good agreement with in vitro experimental data for acute exposure to 60Co γ-rays, thermal neutrons, and BNCT with 10B concentrations of 10 ppm. This indicates that microdosimetric quantities are important parameters for predicting dose-response curves for cell survival under BNCT irradiations. Furthermore, the model estimation at the endpoint of the mean activation dose exhibits a reduced impact of cell recovery during BNCT irradiations with high linear energy transfer (LET) compared to 60Co γ-rays irradiation with low LET. Throughout this study, we discuss the advantages of BNCT for enhancing the killing of cancer cells with a reduced dose-rate dependency. If the neutron spectrum and the timelines for drug and dose delivery are provided, the present model will make it possible to predict radiosensitivity for more realistic dose-delivery schemes in BNCT irradiations.

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Section: Introductionmentioning

confidence: 99%

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mentioning

confidence: 99%

A Model for Estimating Dose-Rate Effects on Cell-Killing of Human Melanoma after Boron Neutron Capture Therapy

Matsuya

Fukunaga

Omura

et al. 2020

Cells

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“…These approaches provide a high level of dose conformity to the target tumour volume, preserving organs at risk 1,2 . Dose-rates used for external irradiation in radiotherapy (i.e., about 4 Gy/min) 3 are much higher than brachytherapy (i.e., about 12 Gy/h or 50 cGy/h) 4 , however some modalities such as IMRT, MRI-linacs 5 and Cyberknife 6 need relatively long times to deliver the prescribed dose compared to previously used methods such as conformal therapy (3D-CRT) 7 . Recent clinical dose-rate studies indicate that cell recovery during irradiation (hereafter called sub-lethal damage repair: SLDR 8,9 ) cannot be ignored, even for the case of high-dose-rate radiation therapy 10 .…”

Section: Introductionmentioning

confidence: 99%

Intensity Modulated Radiation Fields Induce Protective Effects and Reduce Importance of Dose-Rate Effects

Matsuya¹,

McMahon²,

Ghita³

et al. 2019

Sci Rep

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In advanced radiotherapy, intensity modulated radiation fields and complex dose-delivery are utilized to prescribe higher doses to tumours. Here, we investigated the impact of modulated radiation fields on radio-sensitivity and cell recovery during dose delivery. We generated experimental survival data after single-dose, split-dose and fractionated irradiation in normal human skin fibroblast cells (AGO1522) and human prostate cancer cells (DU145). The dose was delivered to either 50% of the area of a T25 flask containing the cells (half-field) or 100% of the flask (uniform-field). We also modelled the impact of dose-rate effects and intercellular signalling on cell-killing. Applying the model to the survival data, it is found that (i) in-field cell survival under half-field exposure is higher than uniform-field exposure for the same delivered dose; (ii) the importance of sub-lethal damage repair (SLDR) in AGO1522 cells is reduced under half-field exposure; (iii) the yield of initial DNA lesions measured with half-field exposure is smaller than that with uniform-field exposure. These results suggest that increased cell survival under half-field exposure is predominantly attributed not to rescue effects (increased SLDR) but protective effects (reduced induction of initial DNA lesions). In support of these protective effects, the reduced DNA damage leads to modulation of cell-cycle dynamics, i.e., less G 1 arrest 6 h after irradiation. These findings provide a new understanding of the impact of dose-rate effects and protective effects measured after modulated field irradiation.

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“…A particular strength of our approach is its simplicity. Unlike other respiratory compensation techniques such as gating, motion tracking, or jet-ventilation, our method eliminates the need for complicated and expensive ancillary techniques and equipment such as seen with MRI-guided SBRT (19,20). Other techniques for motion-compensation for radiation therapy may require implantation of fiducials to determine tumor motion using electromagnetic or x-ray tracking (21,22).…”

Section: Discussionmentioning

confidence: 99%

Histotripsy Ablations in a Porcine Liver Model: Feasibility of Respiratory Motion Compensation by Alteration of the Ablation Zone Prescription Shape

Longo

Zlevor

Laeseke

et al. 2020

Cardiovasc Intervent Radiol

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Ethical approval: "All applicable international, national, and/or institutional guidelines for the care and use of animals were followed." "All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted."Informed consent: "For this type of study informed consent is not required."Consent for publication: "Consent for publication was obtained for every individual person's data included in the study.

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MRI-guided radiotherapy: Opening our eyes to the future

Cited by 8 publications

References 47 publications

A Model for Estimating Dose-Rate Effects on Cell-Killing of Human Melanoma after Boron Neutron Capture Therapy

A Model for Estimating Dose-Rate Effects on Cell-Killing of Human Melanoma after Boron Neutron Capture Therapy

Intensity Modulated Radiation Fields Induce Protective Effects and Reduce Importance of Dose-Rate Effects

Histotripsy Ablations in a Porcine Liver Model: Feasibility of Respiratory Motion Compensation by Alteration of the Ablation Zone Prescription Shape

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