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Nagano T, Matsuya Y, Kaida A, Nojima H, Furuta T, Sato K, Yoshimura R, Miura M. In vitro and in silico study of biological effects on cancer cells in the presence of metallic materials during radiotherapy. JOURNAL OF RADIATION RESEARCH 2024; 65:628-639. [PMID: 39174316 PMCID: PMC11420842 DOI: 10.1093/jrr/rrae062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/26/2024] [Indexed: 08/24/2024]
Abstract
X-ray therapy aims to eliminate tumours while minimizing side effects. Intense mucositis is sometimes induced when irradiating the oral cavity with a dental metal crown (DMC). However, the underlying mechanisms of such inducing radiosensitization by DMC remain uncertain. This study explored the radiosensitizing mechanisms around DMCs in an interdisciplinary approach with cell experiments and Monte Carlo simulation with the PHITS code. Clonogenic survival and nuclear 53BP1 foci of a cell line derived from cervical cancer cells (HeLa cells) were measured post-irradiation with therapeutic X-rays near high-Z materials such as Pb or Au plates, and the experimental sensitizer enhancement ratio (SER) was obtained. Meanwhile, the dose enhancement ratio (DER) and relative biological effectiveness for DNA damage yields were calculated using the PHITS code, by considering the corresponding experimental condition. The experiments show the experimental SER values for cell survival and 53BP1 foci near metals are 1.2-1.4, which agrees well with the calculated DER values. These suggest that the radiosensitizing effects near metal are predominantly attributed to the dose increase. In addition, as a preclinical evaluation, the spatial distributions of DER near DMC are calculated using Computed Tomography Digital Imaging and Communications in Medicine (CT-DICOM) data and a simple tooth model. As a result, the DER values evaluated using the CT-DICOM data were lower than those from a simple tooth model. These findings highlight the challenge of evaluating radiosensitizing effects near DMCs using Digital Imaging and Communications in Medicine (DICOM) images due to volume-averaging effects and emphasize the need for a high-resolution (<1 mm) dose assessment method unaffected by these effects.
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Affiliation(s)
- Takuya Nagano
- Department of Radiation Therapeutics and Oncology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Yusuke Matsuya
- Nuclear Science and Engineering Research Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan
- Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Atsushi Kaida
- Department of Dental Radiology and Radiation Oncology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Hitomi Nojima
- Department of Dental Radiology and Radiation Oncology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Takuya Furuta
- Nuclear Science and Engineering Research Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan
| | - Kaoru Sato
- Nuclear Science and Engineering Research Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195, Japan
| | - Ryoichi Yoshimura
- Department of Radiation Therapeutics and Oncology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Masahiko Miura
- Department of Dental Radiology and Radiation Oncology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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Potter S, Maxwell C, Rijken J. The accuracy of Eclipse AXB and AAA dose algorithms with dental amalgam. Phys Eng Sci Med 2024:10.1007/s13246-024-01471-4. [PMID: 39141184 DOI: 10.1007/s13246-024-01471-4] [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: 02/04/2024] [Accepted: 07/28/2024] [Indexed: 08/15/2024]
Abstract
High-density materials used for dental restorations are poorly defined in CT imaging due to scanner limitations. Studies have established that Eclipse offers poor agreement with delivered dose in situations involving high-density material. Defining the accuracy of dose algorithms in situations involving high-density overrides would improve clinical outcomes both for target coverage and OAR sparing. Dental amalgam was placed within a solid water phantom and measurements were taken at 1 cm increments beneath the amalgam down to a depth of 6 cm. Exposed film was compared with Eclipse Treatment Planning system (TPS) calculations on a CT of the experimental setup. The amalgam was overridden with a range of HU values and material selections for dose calculation. AXB performs poorly at describing depth dose downstream of Amalgam, regardless of the override material selected. Applying the known mass density with the Anisotropic Analytical Algorithm (AAA) predicts an average of 1.8% and 2.8% for 6 MV and 10 MV beams. The closest agreement achieved using the Acuros XB (AXB) was overriding with stainless steel, which predicted approximately 1.1% and 1.8% above measured dose for 6 MV and 10 MV respectively. Without overriding the density of amalgam, AAA and AXB return depth dose predictions of 7.3% and 5.8% above film measurement for a 6 MV and 7.6% and 6.5% for 10 MV static beams. Applying override options to a clinical case using an anthropomorphic phantom showed using AXB with Stainless Steel as amalgam override returns the same results as AAA with mass density applied for amalgam. Both of these were in close agreement to the TPS.
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Affiliation(s)
- Sam Potter
- Icon Cancer Centre, Windsor Gardens, SA, Australia.
| | | | - James Rijken
- Icon Cancer Centre, Windsor Gardens, SA, Australia
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Nemoto H, Saito M, Suzuki T, Suzuki H, Sano N, Mochizuki Z, Mochizuki K, Ueda K, Komiyama T, Marino K, Aoki S, Oguri M, Takahashi H, Onishi H. Evaluation of computed tomography metal artifact and CyberKnife fiducial recognition for novel size fiducial markers. J Appl Clin Med Phys 2023; 24:e14142. [PMID: 37672211 PMCID: PMC10691645 DOI: 10.1002/acm2.14142] [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: 12/06/2022] [Revised: 06/28/2023] [Accepted: 08/19/2023] [Indexed: 09/07/2023] Open
Abstract
PURPOSE This study aimed to compare fiducial markers used in CyberKnife treatment in terms of metal artifact intensity observed in CT images and fiducial recognition in the CyberKnife system affected by patient body thickness and type of marker. METHODS Five markers, ACCULOC 0.9 mm × 3 mm, Ball type Gold Anchor (GA) 0.28 mm × 10 mm, 0.28 mm × 20 mm, and novel size GA 0.4 mm × 10 mm, 0.4 mm × 20 mm were evaluated. To evaluate metal artifacts of CT images, two types of CT images of water-equivalent gels with each marker were acquired using Aquilion LB CT scanner, one applied SEMAR (SEMAR-on) and the other did not apply this technique (SEMAR-off). The evaluation metric of artifact intensity (MSD ) which represents a variation of CT values were compared for each marker. Next, 5, 15, and 20 cm thickness of Tough Water (TW) was placed on the gel under the condition of overlapping the vertebral phantom in the Target Locating System, and the live image of each marker was acquired to compare fiducial recognition. RESULTS The mean MSD of SEMAR-off was 78.80, 74.50, 97.25, 83.29, and 149.64 HU for ACCULOC, GA0.28 mm × 10 mm, 20 mm, and 0.40 mm × 10 mm, 20 mm, respectively. In the same manner, that of SEMAR-on was 23.52, 20.26, 26.76, 24.89, and 33.96 HU, respectively. Fiducial recognition decreased in the order of 5, 15, and 20 cm thickness, and GA 0.4 × 20 mm showed the best recognition at thickness of 20 cm TW. CONCLUSIONS We demonstrated the potential to reduce metal artifacts in the CT image to the same level for all the markers we evaluated by applying SEMAR. Additionally, the fiducial recognition of each marker may vary depending on the thickness of the patient's body. Particularly, we showed that GA 0.40 × 20 mm may have more optimal recognition for CyberKnife treatment in cases of high bodily thickness in comparison to the other markers.
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Affiliation(s)
- Hikaru Nemoto
- Department of Advanced Biomedical ImagingUniversity of YamanashiYamanashiJapan
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | - Masahide Saito
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | | | - Hidekazu Suzuki
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | - Naoki Sano
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | | | - Koji Mochizuki
- Kasugai CyberKnife Rehabilitation HospitalYamanashiJapan
| | - Koji Ueda
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | | | - Kan Marino
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | - Shinichi Aoki
- Department of RadiologyUniversity of YamanashiYamanashiJapan
| | - Mitsuhiko Oguri
- Department of RadiologyShizuoka General HospitalShizuokaJapan
| | | | - Hiroshi Onishi
- Department of RadiologyUniversity of YamanashiYamanashiJapan
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Katsura K, Tanabe S, Nakano H, Sakai M, Ohta A, Kaidu M, Soga M, Kobayashi T, Takamura M, Hayashi T. The Relationship between the Contouring Time of the Metal Artifacts Area and Metal Artifacts in Head and Neck Radiotherapy. Tomography 2023; 9:98-104. [PMID: 36648996 PMCID: PMC9844309 DOI: 10.3390/tomography9010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 01/13/2023] Open
Abstract
(1) Background: The impacts of metal artifacts (MAs) on the contouring workload for head and neck radiotherapy have not yet been clarified. Therefore, this study evaluated the relationship between the contouring time of the MAs area and MAs on head and neck radiotherapy treatment planning. (2) Methods: We used treatment planning computed tomography (CT) images for head and neck radiotherapy. MAs were classified into three severities by the percentage of CT images containing MAs: mild (<25%), moderate (25−75%), and severe (>75%). We randomly selected nine patients to evaluate the relationship between MAs and the contouring time of the MAs area. (3) Results: The contouring time of MAs showed moderate positive correlations with the MAs volume and the number of CT images containing MAs. Interobserver reliability of the extracted MAs volume and contouring time were excellent and poor, respectively. (4) Conclusions: Our study suggests that the contouring time of MAs areas is related to individual commitment rather than clinical experience. Therefore, the development of software combining metal artifact reduction methods with automatic contouring methods is necessary to reducing interobserver variability and contouring workload.
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Affiliation(s)
- Kouji Katsura
- Department of Oral Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520, Japan
- Division of Oral and Maxillofacial Radiology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
- Correspondence: ; Tel.: +81-25-227-2914
| | - Satoshi Tanabe
- Division of Radiation Oncology, Niigata University Medical and Dental Hospital, Niigata 851-8520, Japan
| | - Hisashi Nakano
- Division of Radiation Oncology, Niigata University Medical and Dental Hospital, Niigata 851-8520, Japan
| | - Madoka Sakai
- Department of Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
| | - Atsushi Ohta
- Department of Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
| | - Motoki Kaidu
- Department of Radiology and Radiation Oncology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
| | - Marie Soga
- Department of Oral Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520, Japan
| | - Taichi Kobayashi
- Division of Oral and Maxillofacial Radiology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
| | - Masaki Takamura
- Division of Oral and Maxillofacial Radiology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
| | - Takafumi Hayashi
- Department of Oral Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8520, Japan
- Division of Oral and Maxillofacial Radiology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8514, Japan
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Comparison of methods for the handling of metallic dental restorations before head and neck radiotherapy. Support Care Cancer 2022; 30:10285-10290. [PMID: 36239800 DOI: 10.1007/s00520-022-07406-7] [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: 07/12/2022] [Accepted: 10/10/2022] [Indexed: 10/17/2022]
Abstract
PURPOSE During head and neck radiotherapy, backscatter from metallic dental restorations (MDRs) causes oral mucositis. Currently, two MDR handling methods are used: the replacement of MDRs with provisional restorations (MDR removal) and fabrication of dental spacers before radiotherapy. We compared the effects of these two methods on the incidence of oral mucositis during head and neck radiotherapy. METHODS We enrolled 76 patients with MDRs who underwent radiotherapy for head and neck cancer between April 2016 and March 2020. We set grade 2 oral mucositis as an outcome. After adjustment of all covariates using the propensity score (PS), we analyzed the data using a Cox proportional hazards model. In addition, subgroup analysis was performed by stratifying the data into quintiles based on the PS. RESULTS For the incidence of grade 2 oral mucositis due to head and neck radiotherapy, the hazard ratio for the MDR removal group relative to the dental spacer group was 0.344 (95% confidence interval, 0.121-0.980; P = 0.046). Subgroup analysis showed that the hazard ratio for the MDR removal group was 0.339 (95% confidence interval, 0.122-0.943; P = 0.038). CONCLUSION The results suggest that MDR replacement is superior to dental spacer fabrication in reducing the incidence of oral mucositis during head and neck radiotherapy, although MDR removal carries several associated risks.
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Barlaz Us S, Ataol AS, Ergun G. Impact of different fixed dental prostheses on radiation dose in helical tomotherapy as measured with metal oxide semiconductor field-effect transistor dosimetry. Oral Surg Oral Med Oral Pathol Oral Radiol 2022; 133:716-724. [PMID: 35248513 DOI: 10.1016/j.oooo.2022.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 01/03/2022] [Accepted: 01/08/2022] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This ex vivo study evaluated the effects of different fixed dental prostheses and protective materials on scattered radiation during radiation therapy (RT). STUDY DESIGN Natural teeth (group NT) and 4 types of prostheses (group BL: bilayer lithium disilicate glass-ceramic; group MZ: monolithic zirconia ceramic; group BZ: bilayer zirconia-based all ceramic; and group BM: bilayer metal-ceramic restorations) were examined in maxillary and mandibular arch phantoms. All groups were divided into 3 subgroups: (1) without protective material over the prostheses; (2) protected with a soft acrylic night guard; and (3) protected with polyvinylsiloxane putty. All groups were irradiated with helical RT at 2 Gy and 6 MV photon energy. Doses were measured internally and externally 3 times on each phantom. Results were significant at P < .05. RESULTS No statistically significant differences in doses were found between groups NT and BL in either phantom, but these groups were different from the others. The differences between groups BZ and MZ were insignificant. Doses in group BM were significantly larger than all other groups. No significant differences existed between doses with and without protective material. CONCLUSIONS Doses increased significantly due to scattered radiation from the prostheses with increasing material density. Protective materials had no significant effect on dose.
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Affiliation(s)
- Songul Barlaz Us
- Faculty of Medicine, Department of Radiation Oncology, Mersin University, Mersin, Turkey.
| | | | - Gulfem Ergun
- Faculty of Dentistry, Department of Prosthodontics, Gazi University, Ankara, Turkey.
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Ozseven A, Ugurlu M. Assessment of the effects of different dental restorative materials on radiotherapy dose distribution: A phantom study. Niger J Clin Pract 2022; 25:516-523. [PMID: 35439913 DOI: 10.4103/njcp.njcp_1826_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background One of the most specific effects of high-density dental restorative materials on head & neck cancer radiotherapy is generating variations on isodose distributions. These variations might have an impact on the accuracy and effectiveness of the radiation treatment. The aim of this study is investigating the possible dosimetric effect of six different restorative materials on isodose distributions in head & neck radiotherapy planning process. Materials and Methods A special phantom was developed and twenty-one caries-free human third molars (a control group + six different restorative materials) were used for the measurements. After acquiring the computed tomography (CT) images, seven treatment plans were created. Hounsfield Unit (HU) numbers, horizontal line dose profile (HLDP) and vertical line dose profiles (VLDPs) were compared with the control group. Results The amalgam sample deformed the HU numbers in CT images. The median HU value for the S4 material was considerably different than the other samples. The median values were quite close for the remaining samples. For the amalgam sample, the mean of the calculated median isodose values for HLDP and VLDP at 3.5 cm away from the isocenter line were lower than the mean of the control group 4.03% and 6.94%, respectively (for HLDP with tooth numbers of 36 and 38 P = 0.025 and P < 0.001, respectively; for VLDP P < 0.001). In C-S1 comparison results, the statistically significant differences were found for the measurement point at 1 cm away from the isocenter (P = 0.037, P = 0.002, and P = 0.018 for the tooth numbers 36, 37, and 38, respectively). In C-S2 and C-S6 comparisons, there was a statistically significant difference for tooth number 36 (P = 0.035 and P = 0.003, respectively). Conclusions The findings of the present study showed that amalgam should not be used in head & neck cancer patients who are planned to have radiation therapy. A high viscosity glass ionomer cement (GIC) and a ceramic reinforced GIC sample can be used instead of amalgam to minimize the distorting effect on isodose distributions.
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Affiliation(s)
- Alper Ozseven
- Department of Radiation Oncology, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - Muhittin Ugurlu
- Department of Restorative Dentistry, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey
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Development of an x-ray-opaque-marker system for quantitative phantom positioning in patient-specific quality assurance. Phys Med 2021; 91:121-130. [PMID: 34785490 DOI: 10.1016/j.ejmp.2021.10.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/10/2021] [Accepted: 10/30/2021] [Indexed: 11/21/2022] Open
Abstract
PURPOSE We developed an x-ray-opaque-marker (XOM) system with inserted fiducial markers for patient-specific quality assurance (QA) in CyberKnife (Accuray) and a general-purpose linear accelerator (linac). The XOM system can be easily inserted or removed from the existing patient-specific QA phantom. Our study aimed to assess the utility of the XOM system by evaluating the recognition accuracy of the phantom position error and estimating the dose perturbation around a marker. METHODS The recognition accuracy of the phantom position error was evaluated by comparing the known error values of the phantom position with the values measured by matching the images with target locating system (TLS; Accuray) and on-board imager (OBI; Varian). The dose perturbation was evaluated for 6 and 10 MV single-photon beams through experimental measurements and Monte Carlo simulations. RESULTS The root mean squares (RMSs) of the residual position errors for the recognition accuracy evaluation in translations were 0.07 mm with TLS and 0.30 mm with OBI, and those in rotations were 0.13° with TLS and 0.15° with OBI. The dose perturbation was observed within 1.5 mm for 6 MV and 2.0 mm for 10 MV from the marker. CONCLUSIONS Sufficient recognition accuracy of the phantom position error was achieved using our system. It is unnecessary to consider the dose perturbation in actual patient-specific QA. We concluded that the XOM system can be utilized to ensure quantitative and accurate phantom positioning in patient-specific QA with CyberKnife and a general-purpose linac.
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Katsura K, Soga Y, Zenda S, Nishi H, Soga M, Usubuchi M, Mitsunaga S, Tomizuka K, Konishi T, Yatsuoka W, Ueno T, Aragaki T, Hayashi T. A cost-minimization analysis of measures against metallic dental restorations for head and neck radiotherapy. JOURNAL OF RADIATION RESEARCH 2021; 62:374-378. [PMID: 33618357 PMCID: PMC7973474 DOI: 10.1093/jrr/rrab003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/14/2020] [Indexed: 05/12/2023]
Abstract
The aim of this study was to compare the estimated public medical care cost of measures to address metallic dental restorations (MDRs) for head and neck radiotherapy using high-energy mega-voltage X-rays. This was considered a first step to clarify which MDR measure was more cost-effective. We estimated the medical care cost of radiotherapy for two representative MDR measures: (i) with MDR removal or (ii) without MDR removal (non-MDR removal) using magnetic resonance imaging and a spacer. A total of 5520 patients received head and neck radiation therapy in 2018. The mean number of MDRs per person was 4.1 dental crowns and 1.3 dental bridges. The mean cost per person was estimated to be 121 720 yen for MDR removal and 54 940 yen for non-MDR removal. Therefore, the difference in total public medical care cost between MDR removal and non-MDR removal was estimated to be 303 268 800 yen. Our results suggested that non-MDR removal would be more cost-effective than MDR removal for head and neck radiotherapy. In the future, a national survey and cost-effectiveness analysis via a multicenter study are necessary; these investigations should include various outcomes such as the rate of local control, status of oral mucositis, frequency of hospital visits and efforts of the medical professionals.
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Affiliation(s)
- Kouji Katsura
- Corresponding author: Division of Oral and Maxillofacial Radiology, Faculty of Dentistry and Graduate School of Medical and Dental Sciences, Niigata University, 2-5274 Gakkocho-dori, Chuo-ku, Niigata City, Niigata 951-8514, Japan. Tel: +81-25-227-0810;
| | - Yoshihiko Soga
- Division of Hospital Dentistry, Okayama University Hospital, Japan
| | - Sadatomo Zenda
- Department of Radiation Oncology, National Cancer Center Hospital East, Japan
| | - Hiromi Nishi
- Department of General Dentistry, Hiroshima University Hospital, Japan
| | - Marie Soga
- Department of Oral Radiology, Niigata University Medical and Dental Hospital, Japan
| | | | - Sachiyo Mitsunaga
- Department of Oral and Maxillofacial Surgery, Kanagawa Cancer Center, Japan
| | - Ken Tomizuka
- Department of Dentistry, The Cancer Institute Hospital of Japanese Foundation for Cancer Research, Japan
| | - Tetsuhito Konishi
- Department of Dentistry, National Cancer Center Hospital East, Japan
| | | | - Takao Ueno
- Dental Division, National Cancer Center Hospital, Japan
| | - Tadanobu Aragaki
- Division of Dentistry and Oral Surgery, Gunma Prefectural Cancer Center, Japan
| | - Takafumi Hayashi
- Department of Oral Radiology, Niigata University Medical and Dental Hospital, Japan
- Division of Oral and Maxillofacial Radiology, Faculty of Dentistry and Graduate School of Medical and Dental Sciences, Niigata University, Japan
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Kitagawa K, Ikushima H, Sasaki M, Furutani S, Kawanaka T, Kubo A, Tonoiso C, Kudoh T, Kano Y, Tsuzuki A. Effect of dental metal artifact conversion volume on dose distribution in head-and-neck volumetric-modulated arc therapy. J Appl Clin Med Phys 2020; 21:253-262. [PMID: 33226172 PMCID: PMC7769385 DOI: 10.1002/acm2.13101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 11/26/2022] Open
Abstract
Purpose During treatment planning for head‐and‐neck volumetric‐modulated arc therapy (VMAT), manual contouring of the metal artifact area of artificial teeth is done, and the area is replaced with water computed tomography (CT) values for dose calculation. This contouring of the metal artifact areas, which is performed manually, is subject to human variability. The purpose of this study is to evaluate and analyze the effect of inter‐observer variation on dose distribution. Methods The subjects were 25 cases of cancer of the oropharynx for which VMAT was performed. Six radiation oncologists (ROs) performed metal artifact contouring for all of the cases. Gross tumor volume, clinical target volume, planning target volume (PTV), and oral cavity were evaluated. The contouring of the six ROs was divided into two groups, small and large groups. A reference RO was determined for each group and the dose distribution was compared with those of the other radiation oncologists by gamma analysis (GA). As an additional experiment, we changed the contouring of each dental metal artifact area, creating enlarged contours (L), reduced contours (S), and undrawn contours (N) based on the contouring by the six ROs and compared these structure sets. Results The evaluation of inter‐observer variation showed no significant difference between the large and small groups, and the GA pass rate was 100%. Similar results were obtained comparing structure sets L and S, but in the comparison of structure sets L and N, there were cases with pass rates below 70%. Conclusions The results show that the artificial variability of manual artificial tooth metal artifact contouring has little effect on the dose distribution of VMAT. However, it should be noted that the dose distribution may change depending on the contouring method in cases where the overlap between PTV and metal artifact areas is large.
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Affiliation(s)
- Kenta Kitagawa
- Graduate School of Health Sciences, Tokushima University, Tokushima, 770-8503, Japan
| | - Hitoshi Ikushima
- Department of Therapeutic Radiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Motoharu Sasaki
- Department of Therapeutic Radiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Shunsuke Furutani
- Department of Radiology and Radiation Oncology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Takashi Kawanaka
- Department of Radiology and Radiation Oncology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Akiko Kubo
- Department of Radiology and Radiation Oncology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Chisato Tonoiso
- Department of Radiology and Radiation Oncology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Takaharu Kudoh
- Department of Oral and Maxillofacial Surgery, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, 770-8503, Japan
| | - Yosuke Kano
- Graduate School of Health Sciences, Tokushima University, Tokushima, 770-8503, Japan
| | - Akira Tsuzuki
- Department of Radiological Technology, Kochi Medical School Hospital, Nankoku-shi, Kochi, 783-8505, Japan
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Hajhamid B, De Souza GM. Irradiation therapy and chewing simulation: effect on zirconia and human enamel. J Prosthodont Res 2020; 65:249-254. [PMID: 33041279 DOI: 10.2186/jpr.jpr_d_20_00018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE Ionizing radiation therapy (RT) is the main option for head and neck cancer treatment, but it is associated with multiple side effects. This study aimed to evaluate the effect of RT associated with chewing simulation on the surface of human enamel and Yttria-partially stabilized zirconia (Y-TZP). METHODS Maxillary premolar cusps and Y-TZP slabs were divided in 7 experimental groups: CO: no RT (control); EZ groups had irradiation applied to both, enamel and zirconia samples (simulating restoration prior to RT); E groups had irradiation applied to enamel only (simulating restoration after RT). RT doses were either 30, 50 or 70 Gray (Gy). Enamel cusps were abraded against zirconia slabs in a chewing simulator (CS - one million cycles/ 80 N/ 60 mm/min, 2 mm horizontal path, artificial saliva, 37˚ C). Zirconia hardness was evaluated before CS; zirconia roughness and enamel volume (wear) were evaluated before and after CS. Hardness and wear data were analyzed by one-way Analysis of Variance and Tukey post hoc test. Roughness was analyzed by Repeated Measures test and Bonferroni test (p=0.05). RESULTS There was no significant effect of enamel or zirconia irradiation on enamel cusp wear (p=0.226), regardless of the irradiation dose used - up to 70 Gy. Irradiation also did not affect Y-TZP surface roughness (p=0.127) and hardness (p=0.964). CONCLUSIONS RT does not promote significant changes to the surface characteristics of zirconia. Irradiated enamel abraded against zirconia does not show higher wear volume when compared to non-irradiated enamel.
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Furuya T, Lee YK, Archibald-Heeren BR, Byrne M, Bosco B, Phua JH, Shimizu H, Hashimoto S, Tanaka H, Sahgal A, Karasawa K. Evaluation of multi-institutional end-to-end testing for post-operative spine stereotactic body radiation therapy. Phys Imaging Radiat Oncol 2020; 16:61-68. [PMID: 33458345 PMCID: PMC7807765 DOI: 10.1016/j.phro.2020.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/18/2020] [Accepted: 09/22/2020] [Indexed: 12/01/2022] Open
Abstract
BACKGROUND AND PURPOSE Post-operative spine stereotactic body radiation therapy (SBRT) represents a significant challenge as there are many restrictions on beam geometry to avoid metal hardware as it surrounds the target volume. In this study, an international multi-institutional end-to-end test using an in-house spine phantom was developed and executed. The aim was to evaluate the impact of titanium spine hardware on planned and delivered dose for post-operative spine SBRT. MATERIALS AND METHODS Five centers performed simulation, planning and irradiation of the spine phantom, with/without titanium metal hardware (MB/B), following our pre-specified protocol. The doses were calculated using the centers' treatment planning system (TPS) and measured with radiophotoluminescent glass dosimeters (RPLDs) embedded within each phantom. RESULTS The dose differences between the RPLD measured and calculated doses in the target region were within ± 5% for both phantoms studied. Differences greater than 5% were observed for the spinal cord and the out-of-the target regions due to steeper dose gradient regions that are created in these plans. Dose measurements within ± 3% were observed between RPLDs that were embedded in MB and B inserts. For the spinal cord and the out-of-target regions surrounded by metal hardware, the dose measured using RPLDs was within 3% different near the titanium screws compared to the dose measured near only the metal rods. CONCLUSION We have successfully performed the first multi-institutional end-to-end dose analysis using an in-house phantom built specifically for post-operative spine SBRT. The differences observed between the measured and planned doses in the presence of metal hardware were clinically insignificant.
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Affiliation(s)
- Tomohisa Furuya
- Department of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 1138677 Tokyo, Japan
| | - Young K. Lee
- Department of Radiation Oncology, Sunnybrook Odette Cancer Center, University of Toronto, M4N 3M5 Toronto, Ontario, Canada
| | | | - Mikel Byrne
- Radiation Oncology Centres, Sydney Adventist Hospital, Wahroonga, NSW 2076, Australia
| | - Bruno Bosco
- Radiation Oncology Centres, Sydney Adventist Hospital, Wahroonga, NSW 2076, Australia
| | - Jun H. Phua
- Department of Radiation Oncology, National Cancer Center Singapore, 169610 Singapore, Singapore
| | - Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 4648681 Aichi, Japan
| | - Shimpei Hashimoto
- Department of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 1138677 Tokyo, Japan
| | - Hiroshi Tanaka
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 4648681 Aichi, Japan
| | - Arjun Sahgal
- Department of Radiation Oncology, Sunnybrook Odette Cancer Center, University of Toronto, M4N 3M5 Toronto, Ontario, Canada
| | - Katsuyuki Karasawa
- Department of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 1138677 Tokyo, Japan
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13
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Takei Y, Kamomae T, Monzen H, Nakaya T, Sugita K, Suzuki K, Oguchi H, Tamura M, Nishimura Y. Feasibility of using tungsten functional paper as a thin bolus for electron beam radiotherapy. Phys Eng Sci Med 2020; 43:1101-1111. [PMID: 32785883 DOI: 10.1007/s13246-020-00910-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 07/25/2020] [Indexed: 11/30/2022]
Abstract
Containing 80% tungsten by weight, tungsten functional paper (TFP) is a radiation-shielding material that is lightweight, flexible, disposable, and easy to cut. Through experimental measurements and Monte Carlo simulations, we investigated the feasibility of using TFP as a bolus in electron beam radiotherapy. Commercial boluses of thickness 5 and 10 mm and from one to nine layers of TFPs (0.3-2.7 mm) were positioned on the surface of water-equivalent phantoms. The percentage depth dose curves and transverse dose profiles were measured using a 9-MeV electron beam from a clinical linear accelerator. Normalized to the value at the depth of maximum dose without bolus, the relative doses at the phantom surface for no bolus, 5-mm bolus, 10-mm bolus, 1 TFP, 3 TFPs, 6 TFPs, and 9 TFPs were 78%, 88%, 92%, 84%, 92%, 102%, and 112%, respectively; the therapeutic depths corresponding to a 90% dose level were 29.1 mm, 22.7 mm, 17.7 mm, 26.6 mm, 23.2 mm, 19.3 mm, and 15.8 mm, respectively. The TFP contributed to increased skin dose and provided dose uniformity within the target volume. However, it also resulted in increased lateral constriction and penumbra width. The results of Monte Carlo simulation produced similar trends as the experimental measurements. Our findings suggest that using TFP as a novel thin and flexible skin bolus for electron beam radiotherapy is feasible.
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Affiliation(s)
- Yoshiki Takei
- Department of Radiology, Kindai University Nara Hospital, 1248-1 Otoda-cho, Ikoma, Nara, 630-0293, Japan.,Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Takeshi Kamomae
- Department of Radiology, Graduate School of Medicine, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
| | - Takayoshi Nakaya
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kazuma Sugita
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8560, Japan
| | - Kentaro Suzuki
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Hiroshi Oguchi
- Department of Radiological and Medical Laboratory Sciences, Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan
| | - Mikoto Tamura
- Department of Medical Physics, Graduate School of Medical Sciences, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Faculty of Medicine, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan
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Dragojević I, Kisling K, Scanderbeg D, Mansy G. Hyper-dense foreign bodies found in the bowel during IGRT following brachytherapy. Med Dosim 2020; 46:45-50. [PMID: 32778519 DOI: 10.1016/j.meddos.2020.07.001] [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: 06/02/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022]
Abstract
A 28-year-old female with locally advanced adenocarcinoma of the cervix was undergoing treatment with external beam radiation therapy (EBRT), concurrent chemotherapy and high dose rate brachytherapy (BT). On-board imaging obtained prior to one of her external beam treatments revealed four radiopaque foreign bodies in her abdomen. The patient's treatment was delayed for further work-up of this new finding. Upon further investigation, it was discovered that the patient had recently started taking bismuth subsalicylate tablets (brand name: Pepto-Bismol, Procter & Gamble Co., Cincinnati, OH). A computed tomography (CT) scan of the tablets confirmed the size and Hounsfield Unit (HU) values coincided with the foreign object properties seen on the patient's scan. This unexpected finding is important to recognize as it consequently lead to a delay in treatment, additional imaging, and patient anxiety.
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Affiliation(s)
- Irena Dragojević
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, Chula Vista, CA 91914, USA.
| | - Kelly Kisling
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, Chula Vista, CA 91914, USA
| | - Daniel Scanderbeg
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, Chula Vista, CA 91914, USA
| | - Gina Mansy
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, Chula Vista, CA 91914, USA
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15
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Saadatmand P, Amouheidari A, Shanei A, Abedi I. Dose perturbation due to dental amalgam in the head and neck radiotherapy: A phantom study. Med Dosim 2019; 45:128-133. [PMID: 31537421 DOI: 10.1016/j.meddos.2019.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/22/2019] [Accepted: 08/13/2019] [Indexed: 12/14/2022]
Abstract
Dental amalgam, causes perturbation in photon dose distribution of head and neck (H&N) radiotherapy. The aim of this study was to evaluate the effects of dental amalgam on dose distribution of H&N radiotherapy and accuracy of dose calculations algorithm of commercial treatment planning system (TPS). In this study, the measurements were performed using a constructed H&N anthropomorphic. The sample of healthy teeth and teeth filled by amalgam inserted in the desired segment of the phantom in turn. After scanning and organs segmentation of phantom, intensity-modulated radiation therapy (IMRT) plan including 7 fields in the absence (plan 1) and presence (plan 2) of dental amalgam were created separately. Phantom was irradiated using 6 MV linear accelerator (SIMENS-ARTISTE, 5918). Assessment of the effects of dental amalgam on dose distribution and the accuracy of dose calculation algorithm of TPS was done by measurement and comparing of organ's received dose using thermoluminescent dosimeter (TLDs), placed on a phantom and TPS calculations. The scattering and attenuation due to the presence of dental amalgam led to an increase in parotid glands received dose (up to 24.38%) and a decrease in mean dose (up to -6.25%) PTV70. Results of this study revealed that discrepancies between the collapsed cone convolution (CCC) algorithm calculations Prowess Panther TPS and TLD measurements were -19.77% to 27.49% in presence of amalgam and -1.09% to 5.03% in presence of healthy teeth in phantoms. Attenuation and scattering due to amalgam in IMRT of H&N cancer may lead to a significant dose perturbation which is not predictable by dose calculation of TPS.
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Affiliation(s)
- Pegah Saadatmand
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | | | - Ahmad Shanei
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Iraj Abedi
- Department of Medical Physics, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
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16
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Appendino P, Della Ferrera F, Nassisi D, Blandino G, Gino E, Solla SD, Ruo Redda MG. Are intraoral customized stents still necessary in the era of Highly Conformal Radiotherapy for Head & Neck cancer? Case series and literature review. Rep Pract Oncol Radiother 2019; 24:491-498. [PMID: 31467490 DOI: 10.1016/j.rpor.2019.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 05/19/2019] [Accepted: 07/30/2019] [Indexed: 01/04/2023] Open
Abstract
Aim To evaluate the dose sparing efficacy of intraoral customized stents in combination with IGRT/VMAT in Head & Neck cancer patients. Background Despite advances in high-dose conformal radiotherapy (RT) techniques, adverse effects (such as oral mucositis) during and after RT often require temporary suspension of treatment and affect the quality of life in survivors. Intraoral customized stents can decrease radiation doses in healthy tissues and minimize damage from radiations. At the best of our knowledge the clinical impact of such devices in combination with VMAT (volumetric modulated arc therapy) is not reported in the literature. Cases description Three Head & Neck cancer patients were submitted to image guided (IG) RT/VMAT in their treatment protocol. Dose distribution with and without the use of an intraoral stent was compared in each patient. Mean radiation doses proved to be lower in all patients, especially in the subsite: oral cavity. Conclusions There are several reports on the efficacy of IS during RT for Head & Neck cancer. Despite technological advances, the combination between high conformal RT and intraoral stents could still play a role in the management of this kind of patients. This strengthens the usefulness of the individualization of treatments and multidisciplinary approach.
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Affiliation(s)
- P Appendino
- Department of Dentistry and Oral Surgery, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - F Della Ferrera
- Department of Dentistry and Oral Surgery, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - D Nassisi
- Department of Radiation Oncology, University of Turin School of Medicine, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - G Blandino
- Department of Radiation Oncology, University of Turin School of Medicine, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - E Gino
- Department of Medical Physics, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - S D Solla
- Department of Radiation Oncology, University of Turin School of Medicine, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
| | - M G Ruo Redda
- Department of Radiation Oncology, University of Turin School of Medicine, Mauriziano Umberto I Hospital, Corso Turati 62, 10128 Turin, Italy
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17
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Kamomae T, Monzen H, Kawamura M, Okudaira K, Nakaya T, Mukoyama T, Miyake Y, Ishihara Y, Itoh Y, Naganawa S. Dosimetric feasibility of using tungsten-based functional paper for flexible chest wall protectors in intraoperative electron radiotherapy for breast cancer. Phys Med Biol 2017; 63:015006. [PMID: 29083315 DOI: 10.1088/1361-6560/aa96cf] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Intraoperative electron radiotherapy (IOERT), which is an accelerated partial breast irradiation method, has been used for early-stage breast cancer treatment. In IOERT, a protective disk is inserted behind the target volume to minimize the dose received by normal tissues. However, to use such a disk, the surgical incision must be larger than the field size because the disk is manufactured from stiff and unyielding materials. In this study, the applicability of newly developed tungsten-based functional paper (TFP) was assessed as an alternative to the existing protective disk. The radiation-shielding performance of the TFP was verified through experimental measurements and Monte Carlo simulations. Percentage depth dose curves and lateral dose profiles with and without TFPs were measured and simulated on a dedicated IOERT accelerator. The number of piled-up TFPs was changed from 1 to 40. In the experimental measurements, the relative doses at the exit plane of the TFPs for 9 MeV were 42.7%, 9.2%, 0.2%, and 0.1% with 10, 20, 30, and 40 TFPs, respectively, whereas those for 12 MeV were 63.6%, 27.1%, 8.6%, and 0.2% with 10, 20, 30, and 40 TFPs, respectively. Slight dose enhancements caused by backscatter radiation from the TFPs were observed at the entrance plane of the TFPs at both beam energies. The results of the Monte Carlo simulation indicated the same tendency as the experimental measurements. Based on the experimental and simulated results, the radiation-shielding performances of 30 TFPs for 9 MeV and 40 TFPs for 12 MeV were confirmed to be acceptable and close to those of the existing protective disk. The findings of this study suggest the feasibility of using TFPs as flexible chest wall protectors in IOERT for breast cancer treatment.
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Affiliation(s)
- Takeshi Kamomae
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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18
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Kamomae T, Shimizu H, Nakaya T, Okudaira K, Aoyama T, Oguchi H, Komori M, Kawamura M, Ohtakara K, Monzen H, Itoh Y, Naganawa S. Three-dimensional printer-generated patient-specific phantom for artificial in vivo dosimetry in radiotherapy quality assurance. Phys Med 2017; 44:205-211. [PMID: 29102154 DOI: 10.1016/j.ejmp.2017.10.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 09/11/2017] [Accepted: 10/14/2017] [Indexed: 12/21/2022] Open
Abstract
Pretreatment intensity-modulated radiotherapy quality assurance is performed using simple rectangular or cylindrical phantoms; thus, the dosimetric errors caused by complex patient-specific anatomy are absent in the evaluation objects. In this study, we construct a system for generating patient-specific three-dimensional (3D)-printed phantoms for radiotherapy dosimetry. An anthropomorphic head phantom containing the bone and hollow of the paranasal sinus is scanned by computed tomography (CT). Based on surface rendering data, a patient-specific phantom is formed using a fused-deposition-modeling-based 3D printer, with a polylactic acid filament as the printing material. Radiophotoluminescence glass dosimeters can be inserted in the 3D-printed phantom. The phantom shape, CT value, and absorbed doses are compared between the actual and 3D-printed phantoms. The shape difference between the actual and printed phantoms is less than 1 mm except in the bottom surface region. The average CT value of the infill region in the 3D-printed phantom is -6 ± 18 Hounsfield units (HU) and that of the vertical shell region is 126 ± 18 HU. When the same plans were irradiated, the dose differences were generally less than 2%. These results demonstrate the feasibility of the 3D-printed phantom for artificial in vivo dosimetry in radiotherapy quality assurance.
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Affiliation(s)
- Takeshi Kamomae
- Department of Therapeutic Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hidetoshi Shimizu
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-Ku, Nagoya 464-8681, Aichi, Japan
| | - Takayoshi Nakaya
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan
| | - Kuniyasu Okudaira
- Department of Radiological Technology, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan
| | - Takahiro Aoyama
- Department of Radiation Oncology, Aichi Cancer Center Hospital, 1-1 Kanokoden, Chikusa-Ku, Nagoya 464-8681, Aichi, Japan
| | - Hiroshi Oguchi
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673, Japan
| | - Masataka Komori
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya 461-8673, Japan
| | - Mariko Kawamura
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Kazuhiro Ohtakara
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hajime Monzen
- Department of Medical Physics, Graduate School of Medical Science, Kindai University, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan
| | - Yoshiyuki Itoh
- Department of Therapeutic Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Tomida M, Kamomae T, Suzuki J, Ohashi Y, Itoh Y, Oguchi H, Okuda T. Clinical usefulness of MLCs in robotic radiosurgery systems for prostate SBRT. J Appl Clin Med Phys 2017; 18:124-133. [PMID: 28691256 PMCID: PMC5875821 DOI: 10.1002/acm2.12128] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/13/2017] [Accepted: 06/05/2017] [Indexed: 11/11/2022] Open
Abstract
Stereotactic body radiation therapy (SBRT) using recently introduced multileaf collimators (MLC) is preferred over circular collimators in the treatment of localized prostate cancer. The objective of this study was to assess the clinical usefulness of MLCs in prostate SBRT by comparing the effectiveness of treatment plans using fixed collimators, variable collimators, and MLCs and by ensuring delivery quality assurance (DQA) for each. For each patient who underwent conventional radiation therapy for localized prostate cancer, mock SBRT plans were created using a fixed collimator, a variable collimator, and an MLC. The total MUs, treatment times, and dose-volume histograms of the planning target volumes and organs at risk for each treatment plan were compared. For DQA, a phantom with a radiochromic film or an ionization chamber was irradiated in each plan. We performed gamma-index analysis to evaluate the consistency between the measured and calculated doses. The MLC-based plans had an ~27% lower average total MU than the plans involving other collimators. Moreover, the average estimated treatment time for the MLC plan was 31% and 20% shorter than that for the fixed and variable collimator plans respectively. The gamma-index passing rate in the DQA using film measurements was slightly lower for the MLC than for the other collimators. The DQA results acquired using the ionization chamber showed that the discrepancies between the measured and calculated doses were within 3% in all cases. The results reinforce the usefulness of MLCs in robotic radiosurgery for prostrate SBRT treatment planning; most notably, the total MU and treatment time were both reduced compared to the cases using other types of collimators. Moreover, although the DQA results based on film dosimetry yielded a slightly lower gamma-index passing rate for the MLC than for the other collimators, the MLC accuracy was determined to be sufficient for clinical use.
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Affiliation(s)
- Masashi Tomida
- Department of Radiology, Toyota Memorial Hospital, Toyota, Japan.,Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takeshi Kamomae
- Department of Therapeutic Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Junji Suzuki
- Department of Quality Management for Radiotherapy, Toyota Memorial Hospital, Toyota, Japan
| | - Yoichi Ohashi
- Department of Radiology, Toyota Memorial Hospital, Toyota, Japan
| | - Yoshiyuki Itoh
- Department of Therapeutic Radiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroshi Oguchi
- Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takahito Okuda
- Department of Radiology, Toyota Memorial Hospital, Toyota, Japan
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Utility of intraoral stents in external beam radiotherapy for head and neck cancer. Rep Pract Oncol Radiother 2017; 22:310-318. [PMID: 28515675 DOI: 10.1016/j.rpor.2017.03.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/25/2017] [Accepted: 03/16/2017] [Indexed: 11/21/2022] Open
Abstract
AIM This study aimed to assess the utility and stability of intraoral stent during intensity-modulated radiation therapy (IMRT). BACKGROUND The benefits of intraoral stents in radiotherapy are unclear. MATERIALS AND METHODS We analyzed 386 setup errors in 12 patients who received IMRT for head and neck cancers without intraoral stents (intraoral stent [-]) and 183 setup errors in 6 patients who received IMRT with intraoral stents (intraoral stent [+]). All patients were matched according to the immobilization method (masks and boards). Setup errors were measured as the distance from the initial setup based on the marking on the skin and mask to the corrected position based on bone matching on cone beam computed tomography. RESULTS The mean interfractional setup errors in the right-left, craniocaudal, anterior-posterior (AP), and three-dimensional (3D) directions were -0.33, 0.08, -0.25, and 2.75 mm in the intraoral stent (-) group and -0.37, 0.24, -0.63, and 2.42 mm in the intraoral stent (+) group, respectively (P = 0.50, 0.65, 0.01, and 0.02, respectively). The systematic errors for the same directions were 0.89, 1.46, 1.15, and 0.88 mm in the intraoral stent (-) group and 0.62, 1.69, 0.68, and 0.56 mm in the intraoral stents (+) group, respectively. The random errors were 1.43, 1.43, 1.44, and 1.22 mm in the intraoral stent (-) group and 1.06, 1.11, 1.05, and 0.92 mm in the intraoral stents (+) group, respectively. CONCLUSION Setup errors can be significantly reduced in the AP and 3D-directions by using intraoral stents.
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