• Title, Summary, Keyword: Proton beam therapy

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Dosimetric Impact of Ti Mesh on Proton Beam Therapy

  • Cho, Shinhaeng;Goh, Youngmoon;Kim, Chankyu;Kim, Haksoo;Jeong, Jong Hwi;Lim, Young Kyung;Lee, Se Byeong;Shin, Dongho
    • Progress in Medical Physics
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    • v.28 no.4
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    • pp.144-148
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    • 2017
  • When a high density metallic implant is placed in the path of the proton beam, spatial heterogeneity can be caused due to artifacts in three dimensional (3D) computed tomography (CT) scans. These artifacts result in range uncertainty in dose calculation in treatment planning system (TPS). And this uncertainty may cause significant underdosing to the target volume or overdosing to normal tissue beyond the target. In clinical cases, metal implants must be placed in the beam path in order to preserve organ at risk (OARs) and increase target coverage for tumors. So we should introduce Ti-mesh. In this paper, we measured the lateral dose profile for proton beam using an EBT3 film to confirm dosimetric impact of Ti-mesh when the Ti-mesh plate was placed in the proton beam pathway. The effect of Ti-mesh on the proton beam was investigated by comparing the lateral dose profile calculated from TPS with the film-measured value under the same conditions.

A Pilot Study of the Scanning Beam Quality Assurance Using Machine Log Files in Proton Beam Therapy

  • Chung, Kwangzoo
    • Progress in Medical Physics
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    • v.28 no.3
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    • pp.129-133
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    • 2017
  • The machine log files recorded by a scanning control unit in proton beam therapy system have been studied to be used as a quality assurance method of scanning beam deliveries. The accuracy of the data in the log files have been evaluated with a standard calibration beam scan pattern. The proton beam scan pattern has been delivered on a gafchromic film located at the isocenter plane of the proton beam treatment nozzle and found to agree within ${\pm}1.0mm$. The machine data accumulated for the scanning beam proton therapy of five different cases have been analyzed using a statistical method to estimate any systematic error in the data. The high-precision scanning beam log files in line scanning proton therapy system have been validated to be used for off-line scanning beam monitoring and thus as a patient-specific quality assurance method. The use of the machine log files for patient-specific quality assurance would simplify the quality assurance procedure with accurate scanning beam data.

Development of Beam Monitoring System for Proton Pencil Beam Scanning Using Fiber-Optic Radiation Sensor

  • Son, Jaeman;Koo, Jihye;Moon, Sunyoung;Yoon, Myonggeun;Jeong, Jonghwi;Kim, Sun-Young;Lim, Youngkyung;Lee, Se Byeong;Shin, Dongho;Kim, Meyoung;Kim, Dongwook
    • Journal of the Korean Physical Society
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    • v.71 no.7
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    • pp.438-443
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    • 2017
  • We aimed to develop a beam monitoring system based on a fiber-optic radiation sensor (FORS), which can be used in real time in a beam control room, to monitor a beam in proton therapy, where patients are treated using a pencil beam scanning (PBS) mode, by measuring the beam spot width (BSW) and beam spot position (BSP) of the PBS. We developed two-dimensional detector arrays to monitor the PBS beam in the beam control room. We measured the BSW for five energies of the PBS beam and compared the measurements with those of Lynx and EBT3 film. In order to confirm the BSP, we compared the BSP values of the PBS calculated from radiation treatment planning (RTP), to five BSP values measured using FORS at 224.2 MeV. When comparing BSW values obtained using developed monitoring system to the measurements obtained using commercial EBT3 film, the average difference in BSW value of the PBS beam was $0.1{\pm}0.1mm$. In the comparison of BSW values with the measurements obtained using Lynx, the average difference was $0.2{\pm}0.1mm$. When comparing BSP measurements to the values calculated from RTP, the average difference was $0.4{\pm}0.2mm$. The study results confirmed that the developed FORS-based beam monitoring system can monitor a PBS beam in real time in a beam control room, where proton beam is controlled for the patient.

Radiation Therapy against Pediatric Malignant Central Nervous System Tumors : Embryonal Tumors and Proton Beam Therapy

  • Lim, Do Hoon
    • Journal of Korean Neurosurgical Society
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    • v.61 no.3
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    • pp.386-392
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    • 2018
  • Radiation therapy is highly effective for the management of pediatric malignant central nervous system (CNS) tumors including embryonal tumors. With the increment of long-term survivors from malignant CNS tumors, the radiation-related toxicities have become a major concern and we need to improve the treatment strategies to reduce the late complications without compromising the treatment outcomes. One of such strategies is to reduce the radiation dose to craniospinal axis or radiation volume and to avoid or defer radiation therapy until after the age of three. Another strategy is using particle beam therapy such as proton beams instead of photon beams. Proton beams have distinct physiologic advantages over photon beams and greater precision in radiation delivery to the tumor while preserving the surrounding healthy tissues. In this review, I provide the treatment principles of pediatric CNS embryonal tumors and the strategic improvements of radiation therapy to reduce treatment-related late toxicities, and finally introduce the increasing availability of proton beam therapy for pediatric CNS embryonal tumors compared with photon beam therapy.

Image Based Quality Assurance of Range Compensator for Proton Beam Therapy (양성자치료용 보상체의 영상기반 정도 관리 기반 프로그램 개발)

  • Kim, Jin-Sung;Yoon, Myong-Geun;Kim, Dong-Wook;Lim, Young-Kyung;Kwak, Jung-Won;Park, So-Ah;Shin, Dong-Ho;Shin, Jung-Wook;Lee, Se-Byeong;Park, Sung-Yong;Cho, Kwan-Ho
    • Progress in Medical Physics
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    • v.19 no.1
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    • pp.35-41
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    • 2008
  • The main benefit of proton therapy over photon beam radiotherapy is the absence of exit dose, which offers the opportunity for highly conformal dose distributions to target volume while simultaneously irradiating less normal tissue. For proton beam therapy two patient specific beam modifying devices are used. The aperture is used to shape the transverse extension of the proton beam to the shape of the tumor target and a patient-specific compensator attached to the block aperture when required and used to modify the beam range as required by the treatment plan for the patient. A block of range shifting material, shaped on one face in such a way that the distal end of the proton field in the patient takes the shape of the distal end of the target volume. The mechanical quality assurance of range compensator is an essential procedure to confirm the 3 dimensional patient-specific dose distributions. We proposed a new quality assurance method for range compensator based on image processing using X-ray tube of proton therapy treatment room. The depth information, boundaries of each depth of plan compensatorfile and x-ray image of compensator were analyzed and presented over 80% matching results with proposed QA program.

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Progress on Proton Therapy Facility Project in National Cancer Center, Korea

  • Kim, Jong-Won;Park, Sung-Yong;Park, Dahl;Kim, Dae-Yong;Shin, Kyung-Hwan;Cho, Kwan-Ho
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.180-182
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    • 2002
  • A Proton Therapy Center was established this year in National Cancer Center, Korea. We chose IBA of Belgium as the vendor of the equipment package. A 230 MeV fixed-energy cyclotron will deliver proton beams into two gantry rooms, one horizontal beam room, and one experimental station. The building for the equipment is currently under design with a special emphasis on radiation shielding. Installation of equipments is expected to begin in September next year starting with the first gantry, and the acceptance test will be performed about a year later. To generate therapeutic radiation fields the wobbling method will be a main treatment mode for the first gantry. A pencil beam scanning system on the other hand will be equipped for the second gantry relying on the availability at the time of installation. The beam scanning with intensity modulation adapted will be a most advanced form in radiation therapy known as IMPT. Some details on the project progress, scope of the system, and design of building are described.

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Therapeutic Proton Beam Range Measurement with EBT3 Film and Comparison with Tool for Particle Simulation

  • Lee, Nuri;Kim, Chankyu;Song, Mi Hee;Lee, Se Byeong
    • Progress in Medical Physics
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    • v.30 no.4
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    • pp.112-119
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    • 2019
  • Purpose: The advantages of ocular proton therapy are that it spares the optic nerve and delivers the minimal dose to normal surrounding tissues. In this study, it developed a solid eye phantom that enabled us to perform quality assurance (QA) to verify the dose and beam range for passive single scattering proton therapy using a single phantom. For this purpose, a new solid eye phantom with a polymethyl-methacrylate (PMMA) wedge was developed using film dosimetry and an ionization chamber. Methods: The typical beam shape used for eye treatment is approximately 3 cm in diameter and the beam range is below 5 cm. Since proton therapy has a problem with beam range uncertainty due to differences in the stopping power of normal tissue, bone, air, etc, the beam range should be confirmed before treatment. A film can be placed on the slope of the phantom to evaluate the Spread-out Bragg Peak based on the water equivalent thickness value of PMMA on the film. In addition, an ionization chamber (Pin-point, PTW 31014) can be inserted into a hole in the phantom to measure the absolute dose. Results: The eye phantom was used for independent patient-specific QA. The differences in the output and beam range between the measurement and the planned treatment were less than 1.5% and 0.1 cm, respectively. Conclusions: An eye phantom was developed and the performance was successfully validated. The phantom can be employed to verify the output and beam range for ocular proton therapy.

Quality Verification for Respiratory Gated Proton Therapy (호흡동조 양성자치료의 Quality Verification)

  • Kim, Eun Sook;Jang, Yo Jong;Park, Ji Yeon;Kang, Dong Yun;Yeom, Doo Seok
    • The Journal of Korean Society for Radiation Therapy
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    • v.25 no.2
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    • pp.107-113
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    • 2013
  • Purpose: To verify accuracy of respiratory gated proton therapy by measuring and analyzing proton beam delivered when respiratory gated proton therapy is being performed in our institute. Materials and Methods: The plan data of 3 patients who took respiratory gated proton therapy were used to deliver proton beam from proton therapy system. The manufactured moving phantom was used to apply respiratory gating system to reproduce proton beam which was partially irradiated. The key characteristics of proton beam, range, spreat-out Bragg peak (SOBP) and output factor were measured 5 times and the same categories were measured in the continuous proton beam which was not performed with respiratory gating system. Multi-layer ionization chamber was used to measure range and SOBP, and Scanditronix Wellhofer and farmer chamber was used to measure output factor. Results: The average ranges of 3 patients (A, B, C), who had taken respiratory gated proton therapy or not, were (A) 7.226, 7.230, (B) 12.216, 12.220 and (C) 19.918, 19.920 $g/cm^2$ and average SOBP were (A) 4.950, 4.940, (B) 6.496, 6.512 and (C) 8.486, 8.490 $g/cm^2$. And average output factor were (A) 0.985, 0.984 (B) 1.026, 1.027 and (C) 1.138, 1.136 cGy/MU. The differences of average range were -0.004, -0.004, -0.002 $g/cm^2$, that of SOBP were 0.010, -0.016, -0.004 $g/cm^2$ and that of output factor were 0.001, -0.001, 0.002 cGy/MU. Conclusion: It is observed that the range, SOBP and output factor of proton beam delivered when respiratory gated proton therapy is being performed have the same beam quality with no significant difference compared to the proton beam which was continuously irradiated. Therefore, this study verified the quality of proton beam delivered when respiratory gated proton therapy and confirmed the accuracy of proton therapy using this.

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Determination of Proton Beam Position Based on Prompt Gamma Ray Detection (즉발감마선을 이용한 양성자 빔 위치 측정에 관한 연구)

  • Seo, Kyu-Seok;Kim, Jong-Won;Kim, Chan-Hyeong
    • Proceedings of the Korean Society of Medical Physics Conference
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    • pp.69-71
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    • 2004
  • The proton therapy of radiation therapy methods using Bragg Peak which is proton beam's characteristic dose distribution can give a normal tissue lower dose than cancer, comparing with the former existing radiation therapy methods. For exact treatment and patient' safety, we need to know proton beam's position in body, but a proton beam completely stops at treatment region and proton beam's range is uncertainly made by the variety of organs having each different density, so we aren't able to find a proton beam' position by suitable methods yet. With Monte Carlo Computing Method, as a result that we had simulated prompt gamma detection system using correlation of proton beam's absorbed dose distribution about water and prompt gamma distribution by nuclear interaction occurred by collisions of proton and water's hydrogen atoms, we could confirm that a proton beam's position was able to detect by using simulated prompt gamma detection system in body on the real-time

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