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Lyngholm E, Stokkevåg CH, Lühr A, Tian L, Meric I, Tjelta J, Henjum H, Handeland AH, Ytre-Hauge KS. An updated variable RBE model for proton therapy. Phys Med Biol 2024; 69:125025. [PMID: 38527373 DOI: 10.1088/1361-6560/ad3796] [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: 10/17/2023] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
Objective.While a constant relative biological effectiveness (RBE) of 1.1 forms the basis for clinical proton therapy, variable RBE models are increasingly being used in plan evaluation. However, there is substantial variation across RBE models, and several newin vitrodatasets have not yet been included in the existing models. In this study, an updatedin vitroproton RBE database was collected and used to examine current RBE model assumptions, and to propose an up-to-date RBE model as a tool for evaluating RBE effects in clinical settings.Approach.A proton database (471 data points) was collected from the literature, almost twice the size of the previously largest model database. Each data point included linear-quadratic model parameters and linear energy transfer (LET). Statistical analyses were performed to test the validity of commonly applied assumptions of phenomenological RBE models, and new model functions were proposed forRBEmaxandRBEmin(RBE at the lower and upper dose limits). Previously published models were refitted to the database and compared to the new model in terms of model performance and RBE estimates.Main results.The statistical analysis indicated that the intercept of theRBEmaxfunction should be a free fitting parameter and RBE estimates were clearly higher for models with free intercept.RBEminincreased with increasing LET, while a dependency ofRBEminon the reference radiation fractionation sensitivity (α/βx) did not significantly improve model performance. Evaluating the models, the new model gave overall lowest RMSE and highest R2 score. RBE estimates in the distal part of a spread-out-Bragg-peak in water (α/βx= 2.1 Gy) were 1.24-1.51 for original models, 1.25-1.49 for refits and 1.42 for the new model.Significance.An updated RBE model based on the currently largest database among published phenomenological models was proposed. Overall, the new model showed better performance compared to refitted published RBE models.
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Affiliation(s)
- Erlend Lyngholm
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Camilla Hanquist Stokkevåg
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | - Armin Lühr
- Department of Physics, TU Dortmund University, Dortmund, Germany
| | - Liheng Tian
- Department of Physics, TU Dortmund University, Dortmund, Germany
| | - Ilker Meric
- Department of Computer Science, Electrical Engineering and Mathematical Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Johannes Tjelta
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
| | - Helge Henjum
- Department of Physics and Technology, University of Bergen, Bergen, Norway
| | - Andreas Havsgård Handeland
- Department of Physics and Technology, University of Bergen, Bergen, Norway
- Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway
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Qi Tan H, Yang Calvin Koh W, Kuan Rui Tan L, Hao Phua J, Wei Ang K, Yong Park S, Siang Lew W, Cheow Lei Lee J. Dependence of LET on material and its impact on current RBE model. ACTA ACUST UNITED AC 2019; 64:135022. [DOI: 10.1088/1361-6560/ab1c90] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Choi C, Son A, Lee GH, Shin SW, Park S, Ahn SH, Chung Y, Yu JI, Park HC. Targeting DNA-dependent protein kinase sensitizes hepatocellular carcinoma cells to proton beam irradiation through apoptosis induction. PLoS One 2019; 14:e0218049. [PMID: 31194786 PMCID: PMC6563991 DOI: 10.1371/journal.pone.0218049] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 05/24/2019] [Indexed: 12/12/2022] Open
Abstract
Recent studies have highlighted the implications of genetic variations in the relative biological effectiveness (RBE) of proton beam irradiation over conventional X-ray irradiation. Proton beam radiotherapy is a reasonable radiotherapy option for hepatocellular carcinoma (HCC), but the impact of genetic difference on the HCC RBE remains unknown. Here, we determined proton RBE in human HCC cells by exposing them to various doses of either 6-MV X-rays or 230-MeV proton beams. Clonogenic survival assay revealed variable radiosensitivity of human HCC cell lines with survival fraction at 2 Gy ranging from 0.38 to 0.83 and variable proton RBEs with 37% survival fraction ranging from 1.00 to 1.48. HCC cells appeared more sensitive to proton irradiation than X-rays, with more persistent activation of DNA damage repair proteins over time. Depletion of a DNA damage repair gene, DNA-PKcs, by siRNA dramatically increased the sensitivity of HCC cells to proton beams with a decrease in colony survival and an increase in apoptosis. Our findings suggest that there are large variations in proton RBE in HCC cells despite the use of a constant RBE of 1.1 in the clinic and targeting DNA-PKcs in combination with proton beam therapy may be a promising regimen for treating HCC.
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Affiliation(s)
- Changhoon Choi
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
| | - Arang Son
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
| | - Ga-Haeng Lee
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
| | - Sung-Won Shin
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
- Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Sohee Park
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
| | - Sang Hee Ahn
- Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Yoonsun Chung
- Department of Nuclear Engineering, Hanyang University, Seoul, South Korea
| | - Jeong Il Yu
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
| | - Hee Chul Park
- Department of Radiation Oncology, Samsung Medical Center, Seoul, South Korea
- Sungkyunkwan University School of Medicine, Seoul, South Korea
- * E-mail:
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Recovery from sublethal damage and potentially lethal damage : Proton beam irradiation vs. X‑ray irradiation. Strahlenther Onkol 2017; 194:343-351. [PMID: 29038831 DOI: 10.1007/s00066-017-1223-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 09/26/2017] [Indexed: 01/06/2023]
Abstract
PURPOSE In order to clarify the biological response of tumor cells to proton beam irradiation, sublethal damage recovery (SLDR) and potentially lethal damage recovery (PLDR) induced after proton beam irradiation at the center of a 10 cm spread-out Bragg peak (SOBP) were compared with those seen after X‑ray irradiation. METHODS Cell survival was determined by a colony assay using EMT6 and human salivary gland tumor (HSG) cells. First, two doses of 4 Gy/GyE (Gray equivalents, GyE) were given at an interfraction interval of 0-6 h. Second, five fractions of 1.6 Gy/GyE were administered at interfraction intervals of 0-5 min. Third, a delayed-plating assay involving cells in plateau-phase cultures was conducted. The cells were plated in plastic dishes immediately or 2-24 h after being irradiated with 8 Gy/GyE of X‑rays or proton beams. Furthermore, we investigated the degree of protection from the effects of X‑rays or proton beams afforded by the radical scavenger dimethyl sulfoxide to estimate the contribution of the indirect effect of radiation. RESULTS In both the first and second experiments, SLDR was more suppressed after proton beam irradiation than after X‑ray irradiation. In the third experiment, there was no difference in PLDR between the proton beam and X‑ray irradiation conditions. The degree of protection tended to be higher after X‑ray irradiation than after proton beam irradiation. CONCLUSION Compared with that seen after X‑ray irradiation, SLDR might take place to a lesser extent after proton beam irradiation at the center of a 10 cm SOBP, while the extent of PLDR does not differ significantly between these two conditions.
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Choo DW, Goh SH, Cho YW, Baek HJ, Park EJ, Motoyama N, Kim TH, Kim JY, Kim SS. CHK2 is involved in the p53-independent radiosensitizing effects of valproic acid. Oncol Lett 2017; 13:2591-2598. [PMID: 28454438 PMCID: PMC5403276 DOI: 10.3892/ol.2017.5792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 12/20/2016] [Indexed: 01/10/2023] Open
Abstract
Radiotherapy is an effective treatment for the majority of types of localized solid cancer. However, the risk of side effects to the surrounding normal tissues limits radiotherapeutic approaches. Whilst the mechanism of action of valproic acid, an inhibitor of histone deacetylase, remains unknown, the inhibitor is a potential antineoplastic radiosensitizer. The present study demonstrated the in vitro radiosensitizing effects of valproic acid on the human breast cancer MCF7 cell line, and revealed that valproic acid increased the level of DNA breakage, apoptosis and senescence. In addition, western blot analyses revealed that valproic acid induced tumor suppressor protein (p)53 and p21 expression, and activated checkpoint kinase 2 (CHK2) in MCF7 cells and primary mouse embryonic fibroblasts. Notably, treatment with valproic acid also induced increases in the level of p21 protein levels and CHK2 activity in p53-null colon cancer HCT116 cells. Furthermore, the present study demonstrated that valproic acid-induced radiosensitization was largely dependent on the activity of CHK2. The results of the present study reveal that valproic acid may exhibit clinical utility with respect to increasing the anticancer efficacy of radiotherapy by affecting the level of p53.
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Affiliation(s)
- Dong Wan Choo
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Sung Ho Goh
- Cancer Genomics Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Young Woo Cho
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea.,Colgate University, Hamilton, NY 13346, USA
| | - Hye Jung Baek
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Eun Jung Park
- Cancer Immunology Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Noboru Motoyama
- Department of Cognitive Brain Science, National Centre for Geriatrics and Gerontology, Obu, Aichi 474-8522, Japan.,Department of Aging Research, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Tae Hyun Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Joo Young Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
| | - Sang Soo Kim
- Radiation Medicine Branch, National Cancer Center, Goyang, Gyeonggi 410-769, Republic of Korea
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Ablative dose proton beam therapy for stage I and recurrent non-small cell lung carcinomas : Ablative dose PBT for NSCLC. Strahlenther Onkol 2016; 192:649-57. [PMID: 27282279 DOI: 10.1007/s00066-016-0985-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/21/2016] [Indexed: 12/25/2022]
Abstract
PURPOSE To evaluate the efficacy and safety of ablative dose hypofractionated proton beam therapy (PBT) for patients with stage I and recurrent non-small cell lung carcinoma (NSCLC). PATIENTS AND METHODS A total of 55 patients with stage I (n = 42) and recurrent (n = 13) NSCLC underwent hypofractionated PBT and were retrospectively reviewed. A total dose of 50-72 CGE (cobalt gray equivalent) in 5-12 fractions was delivered. RESULTS The median follow-up duration was 29 months (range 4-95 months). There were 24 deaths (43.6%) during the follow-up period: 11 died of disease progression and 13 from other causes. Kaplan-Meier overall survival rate (OS) at 3 years was 54.9% and the median OS was 48.6 months (range 4-95 months). Local progression was observed in 7 patients and the median time to local progression was 9.3 months (range 5-14 months). Cumulative actuarial local control rate (LCR), lymph node metastasis-free survival, and distant metastasis-free survival rates at 3 years were 85.4, 78.4, and 76.5%, respectively. Larger tumor diameter was significantly associated with poorer LCR (3-year: 94% for ≤3 cm vs. 65% for >3 cm, p = 0.006) on univariate analysis and also an independent prognostic factor for LCR (HR 6.9, 95% CI = 1.3-37.8, p = 0.026) on multivariate analysis. No grade 3 or 4 treatment-related toxicities developed. One grade 5 treatment-related adverse event occurred in a patient with symptomatic idiopathic pulmonary fibrosis. CONCLUSIONS Ablative dose hypofractionated PBT was safe and promising for stage I and recurrent NSCLC.
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Maeda K, Yasui H, Matsuura T, Yamamori T, Suzuki M, Nagane M, Nam JM, Inanami O, Shirato H. Evaluation of the relative biological effectiveness of spot-scanning proton irradiation in vitro. JOURNAL OF RADIATION RESEARCH 2016; 57:307-11. [PMID: 26838131 PMCID: PMC4915538 DOI: 10.1093/jrr/rrv101] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/02/2015] [Accepted: 12/07/2015] [Indexed: 05/22/2023]
Abstract
Variations in relative biological effectiveness (RBE) from a fixed value of 1.1 are critical in proton beam therapy. To date, studies estimating RBE at multiple positions relative to the spread-out Bragg peak (SOBP) have been predominantly performed using passive scattering methods, and limited data are available for spot-scanning beams. Thus, to investigate the RBE of spot-scanning beams, Chinese hamster fibroblast V79 cells were irradiated using the beam line at the Hokkaido University Hospital Proton Therapy Center. Cells were placed at six different depths, including the entrance of the proton beam and the proximal and distal part of the SOBP. Surviving cell fractions were analyzed using colony formation assay, and cell survival curves were obtained by the curve fitted using a linear-quadratic model. RBE10 and RBE37 were 1.15 and 1.21 at the center of the SOBP, respectively. In contrast, the distal region showed higher RBE values (1.50 for RBE10 and 1.85 for RBE37). These results are in line with those of previous studies conducted using passive scattering proton beams. Taken together, these data strongly suggest that variations in RBE should be considered during treatment planning for spot-scanning beams as well as for passive scattering proton beams.
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Affiliation(s)
- Kenichiro Maeda
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University
| | - Hironobu Yasui
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Taeko Matsuura
- Department of Medical Physics, Proton Beam Therapy Center, Hokkaido University Hospital
| | - Tohru Yamamori
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Motofumi Suzuki
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Masaki Nagane
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Jin-Min Nam
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University
| | - Osamu Inanami
- Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University
| | - Hiroki Shirato
- Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University Global Station for Quantum Medical Science and Engineering, Global Institution for Collaborative Research and Education, Hokkaido University
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Cuaron JJ, Chang C, Lovelock M, Higginson DS, Mah D, Cahlon O, Powell S. Exponential Increase in Relative Biological Effectiveness Along Distal Edge of a Proton Bragg Peak as Measured by Deoxyribonucleic Acid Double-Strand Breaks. Int J Radiat Oncol Biol Phys 2016; 95:62-69. [PMID: 27084629 DOI: 10.1016/j.ijrobp.2016.02.018] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 02/01/2016] [Accepted: 02/03/2016] [Indexed: 11/26/2022]
Abstract
PURPOSE To quantify the relative biological effectiveness (RBE) of the distal edge of the proton Bragg peak, using an in vitro assay of DNA double-strand breaks (DSBs). METHODS AND MATERIALS U2OS cells were irradiated within the plateau of a spread-out Bragg peak and at each millimeter position along the distal edge using a custom slide holder, allowing for simultaneous measurement of physical dose. A reference radiation signal was generated using photons. The DNA DSBs at 3 hours (to assess for early damage) and at 24 hours (to assess for residual damage and repair) after irradiation were measured using the γH2AX assay and quantified via flow cytometry. Results were confirmed with clonogenic survival assays. A detailed map of the RBE as a function of depth along the Bragg peak was generated using γH2AX measurements as a biological endpoint. RESULTS At 3 hours after irradiation, DNA DSBs were higher with protons at every point along the distal edge compared with samples irradiated with photons to similar doses. This effect was even more pronounced after 24 hours, indicating that the impact of DNA repair is less after proton irradiation relative to photons. The RBE demonstrated an exponential increase as a function of depth and was measured to be as high as 4.0 after 3 hours and as high as 6.0 after 24 hours. When the RBE-corrected dose was plotted as a function of depth, the peak effective dose was extended 2-3 mm beyond what would be expected with physical measurement. CONCLUSIONS We generated a highly comprehensive map of the RBE of the distal edge of the Bragg peak, using a direct assay of DNA DSBs in vitro. Our data show that the RBE of the distal edge increases with depth and is significantly higher than previously reported estimates.
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Affiliation(s)
- John J Cuaron
- Memorial Sloan Kettering Cancer Center, New York, New York.
| | - Chang Chang
- Texas Center for Proton Therapy, Irving, Texas
| | | | | | - Dennis Mah
- Procure Proton Therapy Center, Somerset, New Jersey
| | - Oren Cahlon
- Memorial Sloan Kettering Cancer Center, New York, New York
| | - Simon Powell
- Memorial Sloan Kettering Cancer Center, New York, New York
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Iwata H, Ogino H, Hashimoto S, Yamada M, Shibata H, Yasui K, Toshito T, Omachi C, Tatekawa K, Manabe Y, Mizoe JE, Shibamoto Y. Spot Scanning and Passive Scattering Proton Therapy: Relative Biological Effectiveness and Oxygen Enhancement Ratio in Cultured Cells. Int J Radiat Oncol Biol Phys 2016; 95:95-102. [PMID: 27084632 DOI: 10.1016/j.ijrobp.2016.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/16/2015] [Accepted: 01/11/2016] [Indexed: 11/28/2022]
Abstract
PURPOSE To determine the relative biological effectiveness (RBE), oxygen enhancement ratio (OER), and contribution of the indirect effect of spot scanning proton beams, passive scattering proton beams, or both in cultured cells in comparison with clinically used photons. METHODS AND MATERIALS The RBE of passive scattering proton beams at the center of the spread-out Bragg peak (SOBP) was determined from dose-survival curves in 4 cell lines using 6-MV X rays as controls. Survival of 2 cell lines after spot scanning and passive scattering proton irradiation was then compared. Biological effects at the distal end region of the SOBP were also investigated. The OER of passive scattering proton beams and 6 MX X rays were investigated in 2 cell lines. The RBE and OER values were estimated at a 10% cell survival level. The maximum degree of protection of radiation effects by dimethyl sulfoxide was determined to estimate the contribution of the indirect effect against DNA damage. All experiments comparing protons and X rays were made under the same biological conditions. RESULTS The RBE values of passive scattering proton beams in the 4 cell lines examined were 1.01 to 1.22 (average, 1.14) and were almost identical to those of spot scanning beams. Biological effects increased at the distal end of the SOBP. In the 2 cell lines examined, the OER was 2.74 (95% confidence interval, 2.56-2.80) and 3.08 (2.84-3.11), respectively, for X rays, and 2.39 (2.38-2.43) and 2.72 (2.69-2.75), respectively, for protons (P<.05 for both cells between X rays and protons). The maximum degree of protection was significantly higher for X rays than for proton beams (P<.05). CONCLUSIONS The RBE values of spot scanning and passive scattering proton beams were almost identical. The OER was lower for protons than for X rays. The lower contribution of the indirect effect may partly account for the lower OER of protons.
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Affiliation(s)
- Hiromitsu Iwata
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
| | - Hiroyuki Ogino
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan
| | - Shingo Hashimoto
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan; Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Maho Yamada
- Department of Radiation Oncology, Nagoya City West Medical Center, Nagoya, Japan
| | - Hiroki Shibata
- Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Keisuke Yasui
- Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Toshiyuki Toshito
- Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Chihiro Omachi
- Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya, Japan
| | - Kotoha Tatekawa
- Department of Radiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshihiko Manabe
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Jun-Etsu Mizoe
- Department of Radiation Oncology, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Nagoya, Japan
| | - Yuta Shibamoto
- Department of Radiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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Paganetti H. Relative biological effectiveness (RBE) values for proton beam therapy. Variations as a function of biological endpoint, dose, and linear energy transfer. Phys Med Biol 2014; 59:R419-72. [PMID: 25361443 DOI: 10.1088/0031-9155/59/22/r419] [Citation(s) in RCA: 616] [Impact Index Per Article: 61.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Proton therapy treatments are based on a proton RBE (relative biological effectiveness) relative to high-energy photons of 1.1. The use of this generic, spatially invariant RBE within tumors and normal tissues disregards the evidence that proton RBE varies with linear energy transfer (LET), physiological and biological factors, and clinical endpoint. Based on the available experimental data from published literature, this review analyzes relationships of RBE with dose, biological endpoint and physical properties of proton beams. The review distinguishes between endpoints relevant for tumor control probability and those potentially relevant for normal tissue complication. Numerous endpoints and experiments on sub-cellular damage and repair effects are discussed. Despite the large amount of data, considerable uncertainties in proton RBE values remain. As an average RBE for cell survival in the center of a typical spread-out Bragg peak (SOBP), the data support a value of ~1.15 at 2 Gy/fraction. The proton RBE increases with increasing LETd and thus with depth in an SOBP from ~1.1 in the entrance region, to ~1.15 in the center, ~1.35 at the distal edge and ~1.7 in the distal fall-off (when averaged over all cell lines, which may not be clinically representative). For small modulation widths the values could be increased. Furthermore, there is a trend of an increase in RBE as (α/β)x decreases. In most cases the RBE also increases with decreasing dose, specifically for systems with low (α/β)x. Data on RBE for endpoints other than clonogenic cell survival are too diverse to allow general statements other than that the RBE is, on average, in line with a value of ~1.1. This review can serve as a source for defining input parameters for applying or refining biophysical models and to identify endpoints where additional radiobiological data are needed in order to reduce the uncertainties to clinically acceptable levels.
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Affiliation(s)
- Harald Paganetti
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, 30 Fruit Street, Boston, MA 02114, USA
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Matsumoto Y, Matsuura T, Wada M, Egashira Y, Nishio T, Furusawa Y. Enhanced radiobiological effects at the distal end of a clinical proton beam: in vitro study. JOURNAL OF RADIATION RESEARCH 2014; 55:816-22. [PMID: 24824674 PMCID: PMC4099988 DOI: 10.1093/jrr/rrt230] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 12/13/2013] [Accepted: 12/28/2013] [Indexed: 05/21/2023]
Abstract
In the clinic, the relative biological effectiveness (RBE) value of 1.1 has usually been used in relation to the whole depth of the spread-out Bragg-peak (SOBP) of proton beams. The aim of this study was to confirm the actual biological effect in the SOBP at the very distal end of clinical proton beams using an in vitro cell system. A human salivary gland tumor cell line, HSG, was irradiated with clinical proton beams (accelerated by 190 MeV/u) and examined at different depths in the distal part and the center of the SOBP. Surviving fractions were analyzed with the colony formation assay. Cell survival curves and the survival parameters were obtained by fitting with the linear-quadratic (LQ) model. The RBE at each depth of the proton SOBP compared with that for X-rays was calculated by the biological equivalent dose, and the biological dose distribution was calculated from the RBE and the absorbed dose at each position. Although the physical dose distribution was flat in the SOBP, the RBE values calculated by the equivalent dose were significantly higher (up to 1.56 times) at the distal end than at the center of the SOBP. Additionally, the range of the isoeffective dose was extended beyond the range of the SOBP (up to 4.1 mm). From a clinical point of view, this may cause unexpected side effects to normal tissues at the distal position of the beam. It is important that the beam design and treatment planning take into consideration the biological dose distribution.
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Affiliation(s)
- Yoshitaka Matsumoto
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Taeko Matsuura
- Advanced Medical Sciences, Graduate School of Medicine, Hokkaido University, 15-7 Kita, Kita-ku, Sapporo, Hokkaido, 060-8638, Japan Research Center for Innovative Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan
| | - Mami Wada
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yusuke Egashira
- Research Center for Innovative Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan
| | - Teiji Nishio
- Research Center for Innovative Oncology, National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan
| | - Yoshiya Furusawa
- Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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Kase Y, Yamashita W, Matsufuji N, Takada K, Sakae T, Furusawa Y, Yamashita H, Murayama S. Microdosimetric calculation of relative biological effectiveness for design of therapeutic proton beams. JOURNAL OF RADIATION RESEARCH 2013; 54:485-93. [PMID: 23179376 PMCID: PMC3650736 DOI: 10.1093/jrr/rrs110] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The authors attempt to establish the relative biological effectiveness (RBE) calculation for designing therapeutic proton beams on the basis of microdosimetry. The tissue-equivalent proportional counter (TEPC) was used to measure microdosimetric lineal energy spectra for proton beams at various depths in a water phantom. An RBE-weighted absorbed dose is defined as an absorbed dose multiplied by an RBE for cell death of human salivary gland (HSG) tumor cells in this study. The RBE values were calculated by a modified microdosimetric kinetic model using the biological parameters for HSG tumor cells. The calculated RBE distributions showed a gradual increase to about 1cm short of a beam range and a steep increase around the beam range for both the mono-energetic and spread-out Bragg peak (SOBP) proton beams. The calculated RBE values were partially compared with a biological experiment in which the HSG tumor cells were irradiated by the SOBP beam except around the distal end. The RBE-weighted absorbed dose distribution for the SOBP beam was derived from the measured spectra for the mono-energetic beam by a mixing calculation, and it was confirmed that it agreed well with that directly derived from the microdosimetric spectra measured in the SOBP beam. The absorbed dose distributions to planarize the RBE-weighted absorbed dose were calculated in consideration of the RBE dependence on the prescribed absorbed dose and cellular radio-sensitivity. The results show that the microdosimetric measurement for the mono-energetic proton beam is also useful for designing RBE-weighted absorbed dose distributions for range-modulated proton beams.
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Affiliation(s)
- Yuki Kase
- Proton Therapy Division, Shizuoka Cancer Center Research Institute, 1007, Shimonagakubo, Nagaizumi-cho, Shizuoka 411-8777, Japan.
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Yu Z, Vanstalle M, La Tessa C, Jiang GL, Durante M. Biophysical characterization of a relativistic proton beam for image-guided radiosurgery. JOURNAL OF RADIATION RESEARCH 2012; 53:620-627. [PMID: 22843629 PMCID: PMC3393345 DOI: 10.1093/jrr/rrs007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 02/27/2012] [Indexed: 06/01/2023]
Abstract
We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1-10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery.
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Affiliation(s)
- Zhan Yu
- Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, 64291 Darmstadt, Germany
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, 270 Dong An Road, 200032 Shanghai, China
| | - Marie Vanstalle
- Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, 64291 Darmstadt, Germany
| | - Chiara La Tessa
- Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, 64291 Darmstadt, Germany
| | - Guo-Liang Jiang
- Department of Radiation Oncology, Fudan University Shanghai Cancer Center, 270 Dong An Road, 200032 Shanghai, China
| | - Marco Durante
- Biophysics Department, GSI Helmholtz Center for Heavy Ions Research, Planckstraße 1, 64291 Darmstadt, Germany
- Institute of Condensed Matter Physics, Darmstadt University of Technology, Hochshulstraße 3, 64289 Darmstadt, Germany
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Choi J, Kang JO. Basics of particle therapy II: relative biological effectiveness. Radiat Oncol J 2012; 30:1-13. [PMID: 23120738 PMCID: PMC3475957 DOI: 10.3857/roj.2012.30.1.1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 11/23/2011] [Accepted: 12/02/2011] [Indexed: 01/20/2023] Open
Abstract
In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.
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Affiliation(s)
- Jinhyun Choi
- Department of Radiation Oncology, Kyung Hee University School of Medicine, Seoul, Korea
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Okamoto H, Kohno T, Kanai T, Kase Y, Matsumoto Y, Furusawa Y, Fujita Y, Saitoh H, Itami J. Microdosimetric study on influence of low energy photons on relative biological effectiveness under therapeutic conditions using 6 MV linac. Med Phys 2011; 38:4714-22. [DOI: 10.1118/1.3613152] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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In Vivo Radiobiological Characterization of Proton Beam at the National Cancer Center in Korea: Effect of the Chk2 Mutation. Int J Radiat Oncol Biol Phys 2011; 79:559-62. [DOI: 10.1016/j.ijrobp.2010.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 07/30/2010] [Accepted: 08/07/2010] [Indexed: 11/22/2022]
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17
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Okamoto H, Kanai T, Kase Y, Matsumoto Y, Furusawa Y, Fujita Y, Saitoh H, Itami J, Kohno T. Relation between lineal energy distribution and relative biological effectiveness for photon beams according to the microdosimetric kinetic model. JOURNAL OF RADIATION RESEARCH 2011; 52:75-81. [PMID: 21160135 DOI: 10.1269/jrr.10073] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Our cell survival data showed the obvious dependence of RBE on photon energy: The RBE value for 200 kV X-rays was approximately 10% greater than those for mega-voltage photon beams. In radiation therapy using mega-voltage photon beams, the photon energy distribution outside the field is different with that in the radiation field because of a large number of low energy scattering photons. Hence, the RBE values outside the field become greater. To evaluate the increase in RBE, the method of deriving the RBE using the Microdosimetric Kinetic model (MK model) was proposed in this study. The MK model has two kinds of the parameters, tissue-specific parameters and the dose-mean lineal energy derived from the lineal energy distributions measured with a Tissue-Equivalent Proportional Counter (TEPC). The lineal energy distributions with the same geometries of the cell irradiations for 200 kV X-rays, (60)Co γ-rays, and 6 MV X-rays were obtained with the TEPC and Monte Carlo code GEANT4. The measured lineal energy distribution for 200 kV X-rays was quite different from those for mega-voltage photon beams. The dose-mean lineal energy of 200 kV X-rays showed the greatest value, 4.51 keV/µm, comparing with 2.34 and 2.36 keV/µm for (60)Co γ-rays and 6 MV X-rays, respectively. By using the results of the TEPC and cell irradiations, the tissue-specific parameters in the MK model were determined. As a result, the RBE of the photon beams (y(D): 2~5 keV/µm) in arbitrary conditions can be derived by the measurements only or the calculations only of the dose-mean lineal energy.
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Affiliation(s)
- Hiroyuki Okamoto
- Department of Energy Sciences, Tokyo Institute of Technology, Kanagawa, Japan.
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Matsuura T, Egashira Y, Nishio T, Matsumoto Y, Wada M, Koike S, Furusawa Y, Kohno R, Nishioka S, Kameoka S, Tsuchihara K, Kawashima M, Ogino T. Apparent absence of a proton beam dose rate effect and possible differences in RBE between Bragg peak and plateau. Med Phys 2010; 37:5376-81. [PMID: 21089773 DOI: 10.1118/1.3490086] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Respiration-gated irradiation for a moving target requires a longer time to deliver single fraction in proton radiotherapy (PRT). Ultrahigh dose rate (UDR) proton beam, which is 10-100 times higher than that is used in current clinical practice, has been investigated to deliver daily dose in single breath hold duration. The purpose of this study is to investigate the survival curve and relative biological effectiveness (RBE) of such an ultrahigh dose rate proton beam and their linear energy transfer (LET) dependence. METHODS HSG cells were irradiated by a spatially and temporally uniform proton beam at two different dose rates: 8 Gy/min (CDR, clinical dose rate) and 325 Gy/min (UDR, ultrahigh dose rate) at the Bragg peak and 1.75 (CDR) and 114 Gy/min (UDR) at the plateau. To study LET dependence, the cells were positioned at the Bragg peak, where the absorbed dose-averaged LET was 3.19 keV/microm, and at the plateau, where it was 0.56 keV/microm. After the cell exposure and colony assay, the measured data were fitted by the linear quadratic (LQ) model and the survival curves and RBE at 10% survival were compared. RESULTS No significant difference was observed in the survival curves between the two proton dose rates. The ratio of the RBE for CDR/UDR was 0.98 +/- 0.04 at the Bragg peak and 0.96 +/- 0.06 at the plateau. On the other hand, Bragg peak/plateau RBE ratio was 1.15 +/- 0.05 for UDR and 1.18 +/- 0.07 for CDR. CONCLUSIONS Present RBE can be consistently used in treatment planning of PRT using ultrahigh dose rate radiation. Because a significant increase in RBE toward the Bragg peak was observed for both UDR and CDR, further evaluation of RBE enhancement toward the Bragg peak and beyond is required.
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Affiliation(s)
- Taeko Matsuura
- National Cancer Center Hospital East, 6-5-1 Kashiwanoha, Kashiwa, Chiba 277-8577, Japan.
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Gerelchuluun A, Hong Z, Sun L, Suzuki K, Terunuma T, Yasuoka K, Sakae T, Moritake T, Tsuboi K. Induction of in situ DNA double-strand breaks and apoptosis by 200 MeV protons and 10 MV X-rays in human tumour cell lines. Int J Radiat Biol 2010; 87:57-70. [PMID: 20954835 DOI: 10.3109/09553002.2010.518201] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To clarify the properties of clinical high-energy protons by comparing with clinical high-energy X-rays. MATERIALS AND METHODS Human tumor cell lines, ONS76 and MOLT4, were irradiated with 200 MeV protons or 10 MV X-rays. In situ DNA double-strand breaks (DDSB) induction was evaluated by immunocytochemical staining of phosphorylated histone H2AX (γ-H2AX). Apoptosis was measured by flow-cytometry after staining with Annexin V. The relative biological effectiveness (RBE) was obtained by clonogenic survival assay. RESULTS DDSB induction was significantly higher for protons than X-rays with average ratios of 1.28 (ONS76) and 1.59 (MOLT4) at 30 min after irradiation. However the differences became insignificant at 6 h. Also, apoptosis induction in MOLT4 cells was significantly higher for protons than X-rays with an average ratio of 2.13 at 12 h. However, the difference became insignificant at 20 h. RBE values of protons to X-rays at 10% survival were 1.06 ± 0.04 and 1.02 ± 0.15 for ONS76 and MOLT4, respectively. CONCLUSIONS Cell inactivation may differ according to different timings and/or endpoints. Proton beams demonstrated higher cell inactivation than X-rays in the early phases. These data may facilitate the understanding of the biological properties of clinical proton beams.
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Affiliation(s)
- Ariungerel Gerelchuluun
- Proton Medical Research Center, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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