• Title/Summary/Keyword: Beam Radiation

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The dosimetric Properties of Electron Beam Using Lyon Intraoperative Device for Intraoperative Radiation Therapy (LID (Lyon Intraoperative Device) 이용한 수술중 방사선치료시 전자선의 선량분포 특성)

  • Kim Kye Jun;Park Kyung Ran;Lee Jong Young;Kim Hie Yeon;Sung Ki Jocn;Chu Sung Sil
    • Radiation Oncology Journal
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    • v.10 no.1
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    • pp.85-93
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    • 1992
  • We have studied the dosimetric properties of electron beam using Lyon intraoperative device for intraoperative radiation therapy. The dosimetry data had compiled in such a way that a quick and correct decision regarding the cone shape, energy, and accurate calculations could be made. Using 3 dimensional water phantom, we have got the following data: cone output ratios, surface dose, $d_{max}$, $d_{90}$, flatness, symmetry, beam profiles, isodose curve, and SSD correction factors. The cone output ratios were measured with straight and bevelled cone, respectively. As the cone size and the energy were reduced, the cone output ratios decreased rapidly. With the flattening filter, the surface dose increased by electron beam to $85.3\%$, $89.2\%$, and $93.4\%$, for 6 MeV, 9 MeV, and 12 MeV, respectively. It is important to increase the surface dose to $90\%$ or more. Inspite of diminishing dose rate and beam penetration, this flattening filter increases the treatment volume significantly. With the combination of the three levels collimation and the flattening filter, we achieved good homogeneity of the beam and better flatness and the diameter of the 90$\%$ isodose curve was increased. It is important to increase the area that is included in the $90\%$ isodose level. The value of measured and calculated SSD correction factors did not agree over the clinically important range from 100 cm to 110 cm.

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The first private-hospital based proton therapy center in Korea; status of the Proton Therapy Center at Samsung Medical Center

  • Chung, Kwangzoo;Han, Youngyih;Kim, Jinsung;Ahn, Sung Hwan;Ju, Sang Gyu;Jung, Sang Hoon;Chung, Yoonsun;Cho, Sungkoo;Jo, Kwanghyun;Shin, Eun Hyuk;Hong, Chae-Seon;Shin, Jung Suk;Park, Seyjoon;Kim, Dae-Hyun;Kim, Hye Young;Lee, Boram;Shibagaki, Gantaro;Nonaka, Hideki;Sasai, Kenzo;Koyabu, Yukio;Choi, Changhoon;Huh, Seung Jae;Ahn, Yong Chan;Pyo, Hong Ryull;Lim, Do Hoon;Park, Hee Chul;Park, Won;Oh, Dong Ryul;Noh, Jae Myung;Yu, Jeong Il;Song, Sanghyuk;Lee, Ji Eun;Lee, Bomi;Choi, Doo Ho
    • Radiation Oncology Journal
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    • v.33 no.4
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    • pp.337-343
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    • 2015
  • Purpose: The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. Materials and Methods: The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. Results: The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. Conclusion: The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

Comparison Study on Changes of Antigenicities of Egg Ovalbumin Irradiated by Electron Beam or X-Ray

  • Kim, Mi-Jung;Lee, Ju-Woon;Sung, Nak-Yoon;Kim, Su-Min;Hwang, Young-Jung;Kim, Jae-Hun;Song, Beom-Seok
    • Food Science of Animal Resources
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    • v.34 no.5
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    • pp.570-575
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    • 2014
  • This study was conducted to compare the effects of two forms of radiation (electron and X-ray; generated by an electron beam accelerator) on the conformation and antigenic properties of hen's egg albumin, ovalbumin (OVA), which was used as a model protein. OVA solutions (2.0 mg/mL) were individually irradiated by electron beam or X-ray at the absorbed doses of 0 (control), 2, 4, 6, 8, and 10 kGy. No differences between the two forms of radiation on the structural properties of OVA were shown by spectrometric and electrophoretic analyses. The turbidity of OVA solution increased and the main OVA bands on polyacrylamide gels disappeared after irradiation, regardless of the radiation source. In competitive indirect enzyme-linked immunosorbent assay, OVA samples irradiated by electron beam or X-ray showed different immunological responses in reactions with monoclonal and polyclonal antibodies (immunoglobulin G) produced against non-irradiated OVA. The results indicate that electron beam irradiation and X-ray irradiation produced different patterns of structural changes to the OVA molecule.

Dosimetric Comparison of 6 MV Flattening Filter Free and 6 MV Stereotactic Radiosurgery Beam Using 4 mm Conical Collimator for Trigeminal Neuralgia Radiosurgery

  • Mhatre, Vaibhav R;Chadha, Pranav;Kumar, Abhaya P;Talapatra, Kaustav
    • Journal of Radiation Protection and Research
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    • v.43 no.3
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    • pp.107-113
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    • 2018
  • Background: The purpose of our study was to compare the dosimetric advantages of Flattening filter free (FFF) beams for trigeminal neuralgia patients using 4 mm conical collimators over previously treated patients with 6 MV SRS beam. Materials and Methods: A retrospective study was conducted for 5 TN patients who had been previously treated at our institution using frame-based, LINAC-based stereotactic radiosurgery (SRS) on Novalis Tx using 6 MV SRS beam were replanned on 6X FFF beams on Edge Linear accelerator with same beam angles and dose constraints using 4 mm conical collimator. The total number of monitor units along with the beam on time was compared for both Edge and Novalis Tx by redelivering the plans in QA mode of LINAC to compare the delivery efficiency. Plan quality was evaluated by homogeneity index (HI) and Paddick gradient index (GI) for each plan. We also analyzed the doses to brainstem and organ at risks (OARs). Results and Discussion: A 28% beam-on time reduction was achieved using 6X FFF when compared with 6X SRS beam of Novalis Tx. A sharp dose fall off with gradient index value of $3.4{\pm}0.27$ for 4 mm Varian conical collimator while $4.17{\pm}0.20$ with BrainLab cone. Among the 5 patients treated with a 4 mm cone, average maximum brainstem dose was 10.24 Gy for Edge using 6X FFF and 14.28 Gy for Novalis Tx using 6X SRS beam. Conclusion: The use of FFF beams improves delivery efficiency and conical collimator reduces dose to OAR's for TN radiosurgery. Further investigation is warranted with larger sample patient data.

An Empirical Approach to Dosimetric Effect of Carbon Fiber Couch for Flattening Filter Free Beam of Elekta LINAC

  • Ahn, Sohyun;Park, Kwangwoo;Kim, Jinsung;Lee, Ho;Yoon, Jeongmin;Lee, Eungman;Park, Sohyun;Park, Jeongeun;Kim, Juhye;Keum, Ki Chang
    • Progress in Medical Physics
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    • v.27 no.4
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    • pp.220-223
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    • 2016
  • Generally, it is recommended that the dosimetric effect of carbon fiber couch should be considered especially for an intensity-modulated therapy with a large portion of monitor units from posterior angles. Even a flattening filter free (FFF) beam has been used for stereotactic body radiation therapy (SBRT), the effect of carbon fiber couch for FFF beam is not well known. This work is an effort to evaluate the dosimetric effect of carbon fiber couch for flattened and FFF beam of Elekta linac empirically. The absorbed doses were measured with Farmer type chamber and water-equivalent phantoms with and without couch. And differences of the absorbed doses between with and without couch defined as "couch effect". By comparing calculated dose in treatment planning system (TPS) with measured dose, the optimal density of couch was evaluated. Finally, differences on patient's skin dose and target dose by couch were evaluated in TPS. As a result, the couch effect for 6 and 10 MV flattened beam were -2.71% and -2.32%, respectively. These values were agreed with provided data by vendor within 0.5%. The couch effect for 6 and 10 MV FFF beam were -3.75% and -2.80%, respectively. The patient's skin dose was increased as 18.6% and target dose was decreased as 0.87%, respectively. It was realized that the couch effect of FFF beam was more severe than that of flattened beam. Patient's skin dose and target dose were changed by the couch effect.

Effect of Electron Beam Irradiation on the Anti-allergy Activity of β-Glucan (전자선 조사가 베타글루칸의 항알레르기 활성에 미치는 영향)

  • Park, Jong-Heum;Sung, Nak-Yun;Byun, Eui-Beak;Song, Du-Sup;Kim, Jaekyung;Song, Beom-Seok;Park, Sang-Hyun;Shin, Mi-Hae;Lee, Ju-Woon;Kim, Jae-Hun;Yoo, Young-Choon
    • Journal of Radiation Industry
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    • v.6 no.3
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    • pp.267-272
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    • 2012
  • This study evaluated the change in anti-allergy activity of ${\beta}-glucan$ by electron beam irradiation. ${\beta}-Glucan$ was irradiated at dose of 50 kGy and then orally pre-treated with electron beam irradiated and non irradiated ${\beta}-Glucan$ for 7 days. After pre-treatment, allergy was induced by injection of ovalbumin (OVA). Serum total immunoglobulin E (IgE) and OVA-specific IgE levels in the allergic mice was significantly increased but the mice pre-treated 50 kGy electron beam irradiated ${\beta}-glucan$ was significantly decreased the levels of total IgE and OVA-specific IgE, respectively. Moreover, cytokine production (interleukin-4) was also decreased in the 50 kGy electron beam irradiated ${\beta}-Glucan$ pre-treated mice. These results indicate that pre-treatment of 50 kGy electron beam irradiated ${\beta}-glucan$ may elevate the anti-allergy activity. Therefore, electron beam-irradiated ${\beta}-glucan$ could be used for nutraceutical foods in food industry.

Monte Carlo Algorithm-Based Dosimetric Comparison between Commissioning Beam Data across Two Elekta Linear Accelerators with AgilityTM MLC System

  • Geum Bong Yu;Chang Heon Choi;Jung-in Kim;Jin Dong Cho;Euntaek Yoon;Hyung Jin Choun;Jihye Choi;Soyeon Kim;Yongsik Kim;Do Hoon Oh;Hwajung Lee;Lee Yoo;Minsoo Chun
    • Progress in Medical Physics
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    • v.33 no.4
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    • pp.150-157
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    • 2022
  • Purpose: Elekta synergy® was commissioned in the Seoul National University Veterinary Medical Teaching Hospital. Recently, Chung-Ang University Gwang Myeong Hospital commissioned Elekta Versa HDTM. The beam characteristics of both machines are similar because of the same AgilityTM MLC Model. We compared measured beam data calculated using the Elekta treatment planning system, Monaco®, for each institute. Methods: Beam of the commissioning Elekta linear accelerator were measured in two independent institutes. After installing the beam model based on the measured beam data into the Monaco®, Monte Carlo (MC) simulation data were generated, mimicking the beam data in a virtual water phantom. Measured beam data were compared with the calculated data, and their similarity was quantitatively evaluated by the gamma analysis. Results: We compared the percent depth dose (PDD) and off-axis profiles of 6 MV photon and 6 MeV electron beams with MC calculation. With a 3%/3 mm gamma criterion, the photon PDD and profiles showed 100% gamma passing rates except for one inplane profile at 10 cm depth from VMTH. Gamma analysis of the measured photon beam off-axis profiles between the two institutes showed 100% agreement. The electron beams also indicated 100% agreement in PDD distributions. However, the gamma passing rates of the off-axis profiles were 91%-100% with a 3%/3 mm gamma criterion. Conclusions: The beam and their comparison with MC calculation for each institute showed good performance. Although the measuring tools were orthogonal, no significant difference was found.

Effect of Electron Beam Irradiation on the Properties of Carbon Fiber (전자선 조사에 따른 탄소섬유 물성 변화)

  • Jeun, Joon Pyo;Shin, Hye-Kyoung;Kim, Hyun Bin;Kang, Phil Hyun
    • Journal of Radiation Industry
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    • v.4 no.3
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    • pp.259-263
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    • 2010
  • Carbon fibers are used as a reinforcement material in an epoxy matrix in advanced composites due to their high mechanical strength, rigidity and low specific density. An important aspect of the mechanical properties of composites is associated to the adhesion between the surface of the carbon fiber and the epoxy matrix. This paper aimed to evaluate the effects of electron beam irradiation on the physicochemical properties of carbon fibers to obtain better adhesion properties in resultant composite. Chemical structure and surface elements of carbon fiber were determined by FT-IR, elemental analysis and X-ray photoelectron spectroscopy, which indicated that the oxygen content increased significantly with increasing the radiation dose. Thermal stability of the carbon fibers was studied via the thermalgravimetric analysis. Surface morphology of carbon fiber was analyzed by scanning electron microscope. It was found that the degree of surface roughness was increased by electron beam irradiation.

Quantifications of Intensity-Modulated Radiation Therapy Plan Complexities in Magnetic Resonance Image Guided Radiotherapy Systems

  • Chun, Minsoo;Kwon, Ohyun;Park, Jong Min;Kim, Jung-in
    • Journal of Radiation Protection and Research
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    • v.46 no.2
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    • pp.48-57
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    • 2021
  • Background: In this study, the complexities of step-and-shoot intensity-modulated radiation therapy (IMRT) plans in magnetic resonance-guided radiation therapy systems were evaluated. Materials and Methods: Overall, 194 verification plans from the abdomen, prostate, and breast sites were collected using a 60Co-based ViewRay radiotherapy system (ViewRay Inc., Cleveland, OH, USA). Various plan complexity metrics (PCMs) were calculated for each verification plan, including the modulation complexity score (MCS), plan-averaged beam area (PA), plan-averaged beam irregularity, plan-averaged edge (PE), plan-averaged beam modulation, number of segments, average area among all segments (AA/Seg), and total beam-on time (TBT). The plan deliverability was quantified in terms of gamma passing rates (GPRs) with a 1 mm/2% criterion, and the Pearson correlation coefficients between GPRs and various PCMs were analyzed. Results and Discussion: For the abdomen, prostate, and breast groups, the average GPRs with the 1 mm/2% criterion were 77.8 ± 6.0%, 79.8 ± 4.9%, and 84.7 ± 7.3%; PCMs were 0.263, 0.271, and 0.386; PAs were 15.001, 18.779, and 35.683; PEs were 1.575, 1.444, and 1.028; AA/Segs were 15.37, 19.89, and 36.64; and TBTs were 18.86, 19.33, and 5.91 minutes, respectively. The various PCMs, i.e., MCS, PA, PE, AA/Seg, and TBT, showed statistically significant Pearson correlation coefficients of 0.416, 0.627, -0.541, 0.635, and -0.397, respectively, with GPRs. Conclusion: The area-related metrics exhibited strong correlations with GPRs. Moreover, the AA/Seg metric can be used to estimate the IMRT plan accuracy without beam delivery in the 60Co-based ViewRay radiotherapy system.