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Comparison of the dose perturbation arising from conventional and the novel PEEK prosthesis materials during high energy radiotherapy with 15 MV photons. JOURNAL OF RADIOTHERAPY IN PRACTICE 2021. [DOI: 10.1017/s146039692100056x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Abstract
Aim:
This study aimed to evaluate the dosimetric effects of the metal prosthesis in radiotherapy by Siemens Primus 15 MV linac accelerator. In addition, it proposed the new material could lead to less dose perturbation.
Materials and methods:
The depth dose distributions of typical hip prostheses were calculated for 15 MV photons by MCNP-4C code. Five metal prostheses were selected to reveal the correlation between material type, density and dose perturbations of prostheses. Furthermore, the effects of the location and thickness of the prosthesis on the dose perturbation were also discussed and analysed.
Results:
The results showed that the Co-Cr-Mo alloy as the prosthesis had more influence on the dose at the interface of metal tissue. The dose increased at the entrance of this prosthesis and experienced the reduction when passed through it. Finally, the impact of the new PEEK biomedical polymer materials was also investigated, and the lowest dose perturbations were introduced based on the obtained results.
Conclusion:
It was found that the mean relative dose before and after of PEEK prosthesis was 99·2 and 97·1%, respectively. Therefore, this new biomedical polymer material was proposed to replace the current metal implants.
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Cheraghian M, Pourfallah T, Sabouri-Dodaran AA, Gholami M. Calculation of Photoneutron Contamination of Varian Linac in ICRU Soft-Tissue Phantom Using MCNPX Code. J Med Phys 2021; 46:116-124. [PMID: 34566292 PMCID: PMC8415253 DOI: 10.4103/jmp.jmp_40_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/28/2021] [Accepted: 04/29/2021] [Indexed: 11/04/2022] Open
Abstract
Purpose The aim of this research was to calculate the fluence, dose equivalent (DE), and kerma of thermal, epithermal and fast photoneutrons separately, within ICRU soft-tissue-equivalent phantom in the radiotherapy treatment room, using MCNPX Monte Carlo code. Materials and Methods For this purpose, 18 MV Varian Linac 2100 C/D machine was simulated and desired quantities were calculated on the central axis and transverse directions at different depths. Results Maximum fluence, DE and kerma of total photoneutrons on central axis of the phantom were 43.8 n.cm-2.Gy-1, 0.26, and 3.62 mGy.Gy-1, at depths 2, 0.1, 0.1 cm, respectively. At any depth, average of fluence, DE and kerma in the outer area of the field were less than the inner area and in general were about 72%, 52%, and 45%, respectively. Conclusion According to this research, within the phantom; variation of fluence, DE and kerma in transverse direction were mild, and along the central axis at shallow area were sharp. DE of fast photoneutrons at shallow and deep areas were one order of magnitude greater than thermal photoneutrons.
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Affiliation(s)
| | - Tayyeb Pourfallah
- Department of Biochemistry, Biophysics and Genetics, Medical College, Mazandaran University of Medical Sciences, Sari, Iran.,Department of Medical Physics, Mazandaran University of Medical Sciences, Sari, Iran
| | | | - Mehrdad Gholami
- Department of Medical Physics, School of Allied Medical Sciences, Lorestan University of Medical Sciences, Khorramabad, Iran
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Ghorbani M, Azizi M, Azadegan B, Mowlavi AA, Rahvar ZA, Wagner W. Dosimetric evaluation of neutron contamination caused by dental restorations during photon radiotherapy with a 15 MV Siemens Primus linear accelerator. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.108961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Jayamani J, Osman ND, Tajuddin AA, Mohd Noor N, Abdul Aziz MZ. Dosimetric Comparison between Monaco TPS and EGSnrc Monte Carlo simulation on Titanium Rod in 12bit and 16bit Image Format. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2020. [DOI: 10.1080/16878507.2020.1754042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- J. Jayamani
- School of Health Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia
| | - N. D. Osman
- Oncological and Radiological Sciences Cluster, Advanced Medical and Dental Insitute, Universiti Sains Malaysia, Kepala Batas, Pulau Pinang, Malaysia
| | - A. A. Tajuddin
- Oncological and Radiological Sciences Cluster, Advanced Medical and Dental Insitute, Universiti Sains Malaysia, Kepala Batas, Pulau Pinang, Malaysia
| | - N. Mohd Noor
- Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - M. Z. Abdul Aziz
- Oncological and Radiological Sciences Cluster, Advanced Medical and Dental Insitute, Universiti Sains Malaysia, Kepala Batas, Pulau Pinang, Malaysia
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Tajiki S, Nedaie HA, Rahmani F. A Monte Carlo study of neutron contamination in presence of circular cones during stereotactic radiotherapy with 18 MV photon beams. Biomed Phys Eng Express 2020; 6:035016. [PMID: 33438661 DOI: 10.1088/2057-1976/ab7ff2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
High-energy photons are being used to treat different kinds of cancer, but it may increase the rate of secondary cancers due to the neutron contamination as well as over exposing of patients and medical staffs in radiation therapy Takam, Bezak, Marcu, and Yeoh, 2011, Radiation Research, 176, 508-520. Due to some difficulties in experimental measurements of neutron contamination, Monte Carlo method is an efficient tool to investigate dose parameters and characteristics in new techniques. The 18-MV photon beam of linac and circular cones have been simulated by MCNP5 code. Various parameters of photon and neutron including mean energy, flux, KERMA, the number of particles crossing a surface at a distance of 100 cm (SSD = 100 cm) as well as the change in photon and neutron spectrum as well as in intensity through the transmission in the circular collimators have been investigated. The results of this study show that the use of a circular collimator decreases neutron dose in the central axis, which is an advantage, but neutron contamination inducing small neutron dose is distributed all over the space. On the surface of phantom, photon dose rate is approximately equal to 3.41E7 (mGy/mA.min) for different collimators, but the neutron dose rate is 1.64E2 (mGy/ mA.min), 2.03E2 (mGy/ mA.min) and 2.52E2 (mGy/mA.min) for diameters of 12, 20 and 40 mm, respectively and it decreases by decreasing the diameter of the collimator. The neutron dose rate decreases from 9.68E7 and 9.74E7 (mGy/min.mA) for open field size 33 cm2 and 55 cm2 to 1.64E2 (mGy/min.mA), 2.02E2 (mGy/min.mA) and 2.52E2 (mGy/min.mA) for collimator diameter of 12 mm, 20 mm and 40 mm. It can be concluded that the use of circular collimators has an advantage of reducing neutron dose in the central axis. It should be mentioned that the off-axis neutron dose surrounding the collimator can be eliminated using an external neutron shield without perturbing the treatment field.
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Affiliation(s)
- Sareh Tajiki
- Department of Medical Physics and Biomedical Engineering, Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran. Radiotherapy Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran
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M G, M EB. Dental Materials Effect in Neutron Contamination: Electron Mode of a Linac. J Biomed Phys Eng 2020; 10:155-160. [PMID: 32337182 PMCID: PMC7166217 DOI: 10.31661/jbpe.v0i0.920] [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: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 06/11/2023]
Abstract
BACKGROUND Neutron contamination is produced in electron beams of linac when tooth or dental materials are located in the path of beam. OBJECTIVE This study aims to determine the neutron dose contamination from different dental restoration materials in electron mode of a linac. MATERIAL AND METHODS In this experimental study, the neutron dose contamination was calculated in the presence of tooth and tooth restored by Ceramco C3 veneer, Eclipse or amalgam. The electron mode included 8, 12, and 14 MeV electron beams of Siemens Primus linac at different depths before and after tooth. MCNPX code was used to simulate the linear accelerator and dental restoration materials. Tooth and tooth restoration materials were located in the beams' central axis and the neutron dose was scored in 3 × 3 × 1 cm3 voxels at different depths before and after the tooth. RESULTS The highest neutron dose contamination was observed for the combination of the tooth and Eclipse in 12 and 14 MeV beams and the maximum calculated relative neutron dose was 1.53 for tooth and Eclipse for 14 MeV electron beam. CONCLUSION Tooth and dental materials lead to neutron dose contamination production, therefore, in order to avoid having harmful effects on normal tissues due to the neutron beam in head and neck cancer, it is recommended that treatment planning performed should not place tooth with dental restoration materials in the path of the beam and lower energy electron beams be used.
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Affiliation(s)
- Ghorbani M
- PhD, Biomedical Engineering and Medical Physics Department, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ebrahimi Bardar M
- MSc, Department of Medical Physics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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M R B, F S, S H, S B. Investigating the Impact of Knee Prosthesis in Patients' Body on Radiation Dose Distribution: A Monte Carlo Approach. J Biomed Phys Eng 2019; 9:345-354. [PMID: 31341880 PMCID: PMC6613162 DOI: 10.31661/jbpe.v0i0.1047] [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: 11/05/2018] [Accepted: 12/09/2018] [Indexed: 11/27/2022]
Abstract
Background: Metal prostheses in patients affect the radiotherapy dose distribution. Metal prostheses with high density and atomic number cause major changes in scattering and attenuation of radiation. The present study aims to assess the impact of metal knee prosthesis with various dimensions and materials on radiotherapy dose distribution.
Material and Methods: In this research, the Varian Linac and water phantom were simulated using the MCNPX code. Dose distribution of photon beam in a water phantom, with and without the presence of knee prostheses made of cobalt-chromium-molybdenum alloy, steel, titanium, and titanium alloy used in men and women was investigated using the Monte Carlo simulation.
Results: The prosthesis led to an increase in dose in comparison with cases that there was used no prosthesis. According to values of the depth dose percentage, the maximum dose increase was found to be 6.8%, 6.1%, 4%, and 4.29%, and dose reduction 41.18%, 40.66%, 37.76%, and 37.51% for prosthetics with men’s knee dimensions made of cobalt-chromium-molybdenum alloy, steel, titanium alloy, and titanium, respectively. Above all, does increasing to 6.4%, 5.9%, 3.8%, and 3.94% and doses reducing to 40.87%, 40.36%, 36.94%, and 36.69 were observed in prosthetics for women. The highest amount of dose reduction for men’s prostheses made of mentioned materials was found to be 48.75%, 47.7%, 45%, and 45.8%, respectively. In addition, it was 46.36%, 45.8%, 43.8%, and 43.95% for women’s prostheses, respectively.
Conclusion: Material will have a significant impact if a part of the knee bone places behind the prosthesis. According to the obtained values, it is recommended to utilize prostheses made of titanium and titanium alloys for knee arthroplasty. The prosthesis can either increase or decrease dose in tumor or lead to increase dose at organs at risk.
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Affiliation(s)
- Bayatiani M R
- Ph.D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran
| | - Seif F
- Ph.D of Medical Physics. Assistant professor, Department of Medical Physics and Radiotherapy, Arak university of Medical Sciences and Khansari hospital, Arak, Iran
| | - Hamidi S
- Ph.D of Physics. Associate professor, Department of Physics, Arak University, Arak, Iran
| | - Bagheri S
- Ms.c of Physics, Department of Physics, Arak University, Arak, Iran
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Ghorbani M, Azizi M, Mowlavi AA, Azadegan B. Experimental study of the influence of dental restorations on thermal and fast photo-neutron production in radiotherapy with a high-energy photon beam. Appl Radiat Isot 2019; 147:113-120. [PMID: 30870764 DOI: 10.1016/j.apradiso.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 02/01/2019] [Accepted: 03/04/2019] [Indexed: 10/27/2022]
Abstract
In head and neck radiation therapy, the presence of dental restorations can increase unwanted neutron dose to the patient. This study aimed at the measurement of secondary neutron production induced by irradiation of a healthy tooth, Amalgam, Ni-Cr alloy and Ceramco with a photon beam generated in the treatment head of a Siemens Primus linac at a voltage of 15 MV. The irradiation field amounted to 10 × 10 cm2. The measurements of thermal and fast-neutron equivalent doses were performed by means of CR-39 detectors positioned in various depths of a Perspex (polymethyl methacrylate) phantom as at open field as at presence of corresponding dental restorations. The general trend of thermal neutron as well as fast-neutron equivalent dose behind the denture samples reveals their reduction with increasing depth. The maximum values of thermal-neutron dose related to Amalgam, Ceramco and Ni-Cr alloy amount to 1.45 mSv/100 MU, 1.38 mSv/100 MU and 1.32 mSv/100 MU, whereas the corresponding maximum values of fast-neutron dose at the depth of 1.8 cm amount to 0.19 mSv/100 MU, 1.04 mSv/100 MU and 0.97 mSv/100 MU, respectively. The present study investigates the neutron dose accompanied with radiotherapy. It is recommended that attempts have to be made to ensure that dental restorations are not in the path of the primary high-energy photon beam. Considering treatment planning, the guidelines of radiation protection should be improved.
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Affiliation(s)
- Mahdi Ghorbani
- Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mona Azizi
- Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran.
| | - Ali Asghar Mowlavi
- Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran; Associate Federation Scheme, Medical Physics Field, International Centre for Theoretical Physics (ICTP), Trieste, Italy
| | - Behnam Azadegan
- Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran
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Bahreyni Toossi MT, Khajetash B, Ghorbani M. Assessment of Neutron Contamination Originating from the Presence of Wedge and Block in Photon Beam Radiotherapy. J Biomed Phys Eng 2018; 8:3-12. [PMID: 29732336 PMCID: PMC5928309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Accepted: 03/06/2016] [Indexed: 06/08/2023]
Abstract
BACKGROUND One of the main causes of induction of secondary cancer in radiation therapy is neutron contamination received by patients during treatment. Objective: In the present study the impact of wedge and block on neutron contamination production is investigated. The evaluations are conducted for a 15 MV Siemens Primus linear accelerator. METHODS Simulations were performed using MCNPX Monte Carlo code. 30˚, 45˚ and 60˚ wedges and a cerrobend block with dimensions of 1.5 × 1.5 × 7 cm3 were simulated. The investigation were performed in the 10 × 10 cm2 field size at source to surface distance of 100 cm for depth of 0.5, 2, 3 and 4 cm in a water phantom. Neutron dose was calculated using F4 tally with flux to dose conversion factors and F6 tally. RESULTS Results showed that the presence of wedge increases the neutron contamination when the wedge factor was considered. In addition, 45˚ wedge produced the most amount of neutron contamination. If the block is in the center of the field, the cerrobend block caused less neutron contamination than the open field due to absorption of neutrons and photon attenuation. The results showed that neutron contamination is less in steeper depths. The results for two tallies showed practically equivalent results. CONCLUSION Wedge causes neutron contamination hence should be considered in therapeutic protocols in which wedge is used. In terms of clinical aspects, the results of this study show that superficial tissues such as skin will tolerate more neutron contamination than the deep tissues.
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Affiliation(s)
- M T Bahreyni Toossi
- Medical Physics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - B Khajetash
- Medical Physics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - M Ghorbani
- Medical Physics Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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Yazici G, Sari SY, Yedekci FY, Yucekul A, Birgi SD, Demirkiran G, Gultekin M, Hurmuz P, Yazici M, Ozyigit G, Cengiz M. The dosimetric impact of implants on the spinal cord dose during stereotactic body radiotherapy. Radiat Oncol 2016; 11:71. [PMID: 27225270 PMCID: PMC4880816 DOI: 10.1186/s13014-016-0649-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 05/17/2016] [Indexed: 01/14/2023] Open
Abstract
Background The effects of spinal implants on dose distribution have been studied for conformal treatment plans. However, the dosimetric impact of spinal implants in stereotactic body radiotherapy (SBRT) treatments has not been studied in spatial orientation. In this study we evaluated the effect of spinal implants placed in sawbone vertebra models implanted as in vivo instrumentations. Methods Four different spinal implant reconstruction techniques were performed using the standard sawbone lumbar vertebrae model; 1. L2-L4 posterior instrumentation without anterior column reconstruction (PI); 2. L2-L4 anterior instrumentation, L3 corpectomy, and anterior column reconstruction with a titanium cage (AIAC); 3. L2-L4 posterior instrumentation, L3 corpectomy, and anterior column reconstruction with a titanium cage (PIAC); 4. L2-L4 anterior instrumentation, L3 corpectomy, and anterior column reconstruction with chest tubes filled with bone cement (AIABc). The target was defined as the spinous process and lamina of the lumbar (L) 3 vertebra. A thermoluminescent dosimeter (TLD, LiF:Mg,Ti) was located on the measurement point anterior to the spinal cord. The prescription dose was 8 Gy and the treatment was administered in a single fraction using a CyberKnife® (Accuray Inc., Sunnyvale, CA, USA). We performed two different treatment plans. In Plan A beam interaction with the rod was not limited. In plan B the rod was considered a structure of avoidance, and interaction between the rod and beam was prevented. TLD measurements were compared with the point dose calculated by the treatment planning system (TPS). Results and discussion In plan A, the difference between TLD measurement and the dose calculated by the TPS was 1.7 %, 2.8 %, and 2.7 % for the sawbone with no implant, PI, and PIAC models, respectively. For the AIAC model the TLD dose was 13.8 % higher than the TPS dose; the difference was 18.6 % for the AIABc model. In plan B for the AIAC and AIABc models, TLD measurement was 2.5 % and 0.9 % higher than the dose calculated by the TPS, respectively. Conclusions Spinal implants may be present in the treatment field in patients scheduled to undergo SBRT. For the types of implants studied herein anterior rod instrumentation resulted in an increase in the spinal cord dose, whereas use of a titanium cage had a minimal effect on dose distribution. While planning SBRT in patients with spinal reconstructions, avoidance of the rod and preventing interaction between the rod and beam might be the optimal solution for preventing unexpectedly high spinal cord doses.
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Affiliation(s)
- Gozde Yazici
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey.
| | - Sezin Yuce Sari
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Fazli Yagiz Yedekci
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Altug Yucekul
- Department of Orthopedics and Traumatology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Sumerya Duru Birgi
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Gokhan Demirkiran
- Department of Orthopedics and Traumatology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Melis Gultekin
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Pervin Hurmuz
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Muharrem Yazici
- Department of Orthopedics and Traumatology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Gokhan Ozyigit
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
| | - Mustafa Cengiz
- Department of Radiation Oncology, Hacettepe University, Faculty of Medicine, Ankara, Turkey
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