Development of the Proton Beam Monitoring System at the 45-MeV Proton Irradiation Test Facility

Sang-Pil Yun,In-Seok Hong,Yong-Sub Cho 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.3

A proton beam monitoring system has been developed to measure the intensity and the profile of an external proton beam. The beam monitoring system, which consists of a beam intensity monitor and a beam profile monitor (BPM), can provide the intensity and the profile of a proton beam. As a beam monitor for the intensity measurement, a parallel plate ionization chamber (PPIC) is chosen because of its stable operation and wide dynamic range for the detection of a proton beam. To maintain the beam quality, the PPIC electrodes were fabricated with a very thin aluminized polyester film (25 μm). The structure of the BPM is similar to that of the PPIC, except that the BPM is equipped with a position-sensitive electrode. This position-sensitive electrode allows the BPM to measure the profile of a proton beam. The signals from the beam intensity monitor and the BPM are recorded by using a Lab-view-based PXI system (National Instruments Co.), which displays information on both the intensity and the profile by using a proton beam analysis program supported by Lab-view. As a result, we can monitor information on the proton beam during irradiation tests by using a remote control. A proton beam monitoring system has been developed to measure the intensity and the profile of an external proton beam. The beam monitoring system, which consists of a beam intensity monitor and a beam profile monitor (BPM), can provide the intensity and the profile of a proton beam. As a beam monitor for the intensity measurement, a parallel plate ionization chamber (PPIC) is chosen because of its stable operation and wide dynamic range for the detection of a proton beam. To maintain the beam quality, the PPIC electrodes were fabricated with a very thin aluminized polyester film (25 μm). The structure of the BPM is similar to that of the PPIC, except that the BPM is equipped with a position-sensitive electrode. This position-sensitive electrode allows the BPM to measure the profile of a proton beam. The signals from the beam intensity monitor and the BPM are recorded by using a Lab-view-based PXI system (National Instruments Co.), which displays information on both the intensity and the profile by using a proton beam analysis program supported by Lab-view. As a result, we can monitor information on the proton beam during irradiation tests by using a remote control.

Dosimetry of a Low-energy Proton Beam Using a Plane-parallel Ionization Chamber in the 45-MeV Proton Beam Test Irradiation Facility

윤상필,홍인석,박범식,조용섭 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.22

For the measurement of the absorbed dose in the 45-MeV proton beam test irradiation facility, and air filled ionization chamber technique recommended by the IAEA international code of practice TRS 398 for clinical dosimetry was tested for a radiobiological effect experiment using a proton beam. This work aimed to obtain a calibration factor suitable for our irradiation facility. Applying the TRS 398 protocol, we introduced at this facility the concept of the absorbed dose to water. A parallel-plane Markus ionization chamber and a water phantom were used for proton beam dosimetry. To determine the reference absorbed dose to water for the proton beam, we obtained the beam quality index R_(res) and the beam quality correction factor k_p measuring the depth-to-dose distribution of the proton beam in water. Measurements were made in modulated and unmodulated beams. For the modulated beam, the beam correction factor k_p was 1.00472, and for the unmodulated beam, the beam correction factor k_p was 1.004.

Characterization of Physicochemical Properties of Starch in Barley Irradiated with Proton Beam

Sang Kuk Kim,Shin Young Park,Hak Yoon Kim 韓國作物學會 2013 한국작물학회지 Vol.58 No.3

The study was carried out to determine the gel pasting properties of barley (Hordeum vulgare L. cv. Geoncheonheugbori) as affected by different proton beam irradiation. The λmax, blue value, and amylose content were significantly associated with increasing proton beam irradiation. The pasting time in barley flour irradiated with proton beam ranged 0.09 to 0.16 min shorter than nonirradiated barley flour. Gel pasting temperature ranged 57.4 to 60.5℃. Gel pasting temperature in barley flour decreased with increasing proton beam irradiation. Proton beam irradiation caused a significant decrease in the onset temperature (To), peak temperature (Tp), conclusion temperature (Tc) and enthalpy change (ΔH). Gelatinization range (R) in barley starch was more broaden than that of non-irradiated barley starch. Barley starches gave the strong diffraction peak at around 2θ values15°, 18°, 20°, and 23° 2θ. Peak intensity tended to increase with increased proton beam irradiation. The granule crystallinity is closely associated with decreased amylose and increased amylopectin component. The crystallinity degree of barley starch irradiated with proton beam was significantly increased and it ranged from 24.9 to 32.9% compared to the non-irradiated barley starches. It might be deduced that proton beam irradiation causes significant changes of properties of starch viscosity in rice, especially at high irradiation of proton beam.

Characterization of Physicochemical Properties of Starch in Barley Irradiated with Proton Beam

Kim, Sang Kuk,Park, Shin Young,Kim, Hak Yoon The Korean Society of Crop Science 2013 한국작물학회지 Vol.58 No.3

The study was carried out to determine the gel pasting properties of barley (Hordeum vulgare L. cv. Geoncheonheugbori) as affected by different proton beam irradiation. The ${\lambda}max$, blue value, and amylose content were significantly associated with increasing proton beam irradiation. The pasting time in barley flour irradiated with proton beam ranged 0.09 to 0.16 min shorter than nonirradiated barley flour. Gel pasting temperature ranged 57.4 to $60.5^{\circ}C$. Gel pasting temperature in barley flour decreased with increasing proton beam irradiation. Proton beam irradiation caused a significant decrease in the onset temperature (To), peak temperature (Tp), conclusion temperature (Tc) and enthalpy change (${\Delta}H$). Gelatinization range (R) in barley starch was more broaden than that of non-irradiated barley starch. Barley starches gave the strong diffraction peak at around $2{\Theta}$ values$15^{\circ}$, $18^{\circ}$, $20^{\circ}$, and $23^{\circ}$ $2{\Theta}$. Peak intensity tended to increase with increased proton beam irradiation. The granule crystallinity is closely associated with decreased amylose and increased amylopectin component. The crystallinity degree of barley starch irradiated with proton beam was significantly increased and it ranged from 24.9 to 32.9% compared to the non-irradiated barley starches. It might be deduced that proton beam irradiation causes significant changes of properties of starch viscosity in rice, especially at high irradiation of proton beam.

몬테카를로 시뮬레이션을 이용한 양성자 조사에 따른 Polymer Gel 내부의 선량 분포 특성 평가

박민석,김기섭,정해조,박세영,최인석,김현지,윤용수,김정민 대한방사선과학회 2013 방사선기술과학 Vol.36 No.2

본 연구는 몬테카를로 시뮬레이션을 이용하여 양성자 빔을 피사체에 조사했을 때 발생되는 양성자, 즉발감마선 그리고 양성자 유발 중성자의 3차원적 공간분포를 polymer gel 선량계를 통해 구하고, 이를 물 팬텀에서 조사한 결과와 비교하여 3차원적 선량 분포의 정확성에 대해 알아보고자 한다. 본 연구에서 사용 된 polymergel 선량계는 Gelatin, Methacrylic acid, Hydroquinone, Tetrakis 그리고 증류수로 이루어진 혼합물로 그 밀도는 1.04 g/㎤ 으로 물의 밀도인 0.9998 g/㎤ 과 유사하다. 본 시뮬레이션에서는 72 MeV, 116 MeV, 140MeV 의 양성자 빔이 사용되었다. 양성자 빔은 팬텀의 핵과 반응을 하고 양성자 빔으로 인해 여기된 핵이 다시 안정하게 되기 위해 즉발감마선 그리고 양성자 유발 중성자를 방출한다. 양성자와 즉발감마선 그리고 양성자 유발 중성자는 polymer gel 선량계와 물 팬텀에서 각각 검출하였다. 3차원적 선량 분포를 얻기 위한 검출간격은 2 mm로 하여 선량 분포를 획득하였다. Polymer gel 선량계에서의 양성자의 Bragg-peak를 구해 본 결과 Bragg-peak 지점이 물 팬텀에서의 경우와 유사하게 나타남을 확인 할 수 있었다. 72 MeV, 116 MeV, 그리고 140 MeV의 양성자 빔을 polymer gel 그리고 물 팬텀에 조사했을 때 그 내부에서의 양성자 그리고 즉발감마선의 선량 분포는 polymer gel, 물 팬텀 각각 유사한 선량분포를 가짐을 감마 인덱스 평가로 확인 할 수 있었다. 하지만 양성자 유발 중성자의 경우 물 팬텀에서는 검출이 된 반면 polymer gel 선량계에서는 검출이 되지 않았다. Polymer Gel 선량계는 3차원적 선량 분포를 얻는데 유용한 선량계이지만 양성자 조사 시 그 유발중성자의 검출에는 한계를 보임을 확인할 수 있었다. This study was the estimation of the dose distribution for proton, prompt gamma rays and proton induced neutron particles, in case of exposing the proton beam to polymer gel dosimeter and water phantom. The polymer gel dosimeter was compositeness material of Gelatin, Methacrylic acid, Hydroquinone, Tetrakis and Distilled water. The density of gel dosimeter was 1.04 g/㎤ which was similar to water. The 72, 116 and 140 MeV proton beams were used in the simulation. Proton beam interacted with the nuclei of the phantom and the nuclei in excited states emitted prompt gamma rays and proton induced neutron particles during the process of de-excitation. The proton particles, prompt gamma rays, proton induced neutron particles were detected by polymer gel dosimeter and water phantom, respectively. The gap of the axis for gel was 2 mm. The Bragg-peak for proton particles in gel dosimeter was similar to water phantom. The dose distribution for proton and prompt gamma rays in gel dosimeter and water phantom was approximately identical in case of 72, 116 and 140 MeV for proton beam. However, in case of proton induced neutron particles for 72, 116 and 140 MeV proton beam, particles were not detected in gel dosimeter, while the Water phantom absorbed neutron particles. Considering the resulting data, gel dosimeter which was developed in the normoxic state attentively detected the dose distribution for proton beam exposure except proton induced neutron particles.

Feasibility Test of Flat-Type Faraday Cup for Ultrahigh-Dose-Rate Transmission Proton Beam Therapy

Sang-il Pak,Sungkoo Cho,Seohyeon An,Seonghoon Jeong,Dongho Shin,Youngkyung Lim,Jong Hwi Jeong,Haksoo Kim,Se Byeong Lee Korean Society of Medical Physics 2022 의학물리 Vol.33 No.4

Purpose: Proton therapy has been used for optimal cancer treatment by adapting its Bragg-peak characteristics. Recently, a tissue-sparing effect was introduced in ultrahigh-dose-rate (FLASH) radiation; the high-energy transmission proton beam is considered in proton FLASH therapy. In measuring high-energy/ultrahigh-dose-rate proton beam, Faraday Cup is considered as a dose-rate-independent measurement device, which has been widely studied. In this paper, the feasibility of the simply designed Faraday Cup (Poor Man's Faraday Cup, PMFC) for transmission proton FLASH therapy is investigated. Methods: In general, Faraday cups were used in the measurement of charged particles. The simply designed Faraday Cup and Advanced Markus ion chamber were used for high-energy proton beam measurement in this study. Results: The PMFC shows an acceptable performance, including accuracy in general dosimetric tests. The PMFC has a linear response to the dose and dose rate. The proton fluence was decreased with the increase of depth until the depth was near the proton beam range. Regarding secondary particles backscatter from PMFC, the effect was negligible. Conclusions: In this study, we performed an experiment to investigate the feasibility of PMFC for measuring high-energy proton beams. The PMFC can be used as a beam stopper and secondary monitoring system for transmission proton beam FLASH therapy.

Evaluation of the effect of mechanical deformation on beam isocenter properties of the SC200 scanning beam delivery system

Wang, Ming,Zheng, Jinxing,Song, Yuntao,Li, Ming,Zeng, Xianhu Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

For proton pencil beam scanning (PBS) technology, the accuracy of the dose distribution in a patient is sensitive to the properties of the incident beam. However, mechanical deformation of the proton therapy facility may occur, and this could be an important factor affecting the proton dose distribution in patients. In this paper, we investigated the effect of deformation on an SC200 proton facility's beam isocenter properties. First, mechanical deformation of the PBS nozzle, L-shape plate, and gantry were simulated using a Finite Element code, ANSYS. Then, the impact of the mechanical deformation on the beam's isocenter properties was evaluated using empirical formulas. In addition, we considered the simplest case that could affect the properties of the incident beam (i.e. if only the bending magnet (BG3) has an error in its mounting alignment), and the effect of the beam optics offset on the isocenter characteristics was evaluated. The results showed that the deformation of the beam position in the X and Y direction was less than 0.27 mm, which meets the structural design requirements. Compared to the mechanical deformation of the L-shape plate, the deformation of the gantry had more influence on the beam's isocenter properties. When the error in the mounting alignment of the BG3 is equal to or more than 0.3 mm, the beam deformation at the isocenter exceeds the maximum accepted deformation limits. Generally speaking, for the current design of the SC200 scanning beam delivery system, the effects of mechanical deformation meet the maximum accepted beam deformation limits. In order to further study the effect of the incident beam optics on the isocenter properties, a fine-scale Monte Carlo model including factors relating to the PBS nozzle and the BG3 should be developed in future research.

Biochemical Responses of Soybean (Glycine max L. Merr.) to Proton Beam Irradiation

( Juhyun Im ),( Jonghan Ko ),( Han-yong Kim ),( Bo-keun Ha ) 한국육종학회 2017 Plant Breeding and Biotechnology Vol.5 No.2

The present study evaluated the biochemical effects of proton beam irradiation in soybean. Seeds of two Korean elite cultivars (Kwangan and Pungsannamul) were irradiated by a 57-MeV proton beam in the range of 50-400 Gy. We measured the contents of malondialdehyde (MDA), antioxidant enzymes, and chlorophyll. MDA contents in proton beam-irradiated plants were higher than those in control plants. The activity of antioxidant enzymes differed between the two cultivars. In Kwangan, ascorbate peroxidase (APX) activity increased by 29% relative to the control at 55 Gy and decreased by 58% at 308 Gy. Superoxide dismutase (SOD) and peroxidase (POD) activities decreased by 47 and 25% relative to the control at 55 Gy and recovered to 87 and 56% of that at 55 Gy with 172 Gy and 117 Gy, respectively. In Pungsannamul, APX and SOD decreased by 32 and 35% relative to the control at 62 Gy, with the highest value observed at 243 Gy. In terms of the chlorophyll content, the two varieties responded similarly to proton beam irradiation, whereas in Kwangan, no significant reduction was observed above 100 Gy when compared with the control. Proton beam irradiation affected chlorophyll b more than chlorophyll a. These results show that the activity of antioxidant enzymes decreased in response to irradiation with approximately 50 Gy proton beams, then increased gradually with increasing doses, followed by a moderate decrease at higher doses. According to correlation with MDA contents and antioxidant enzyme activities, defense system of Pungsannamul was less activated by proton-beam irradiation than that of Kwangan.

Characteristics of Movement-Induced Dose Reduction in Target Volume: A Comparison Between Photon and Proton Beam Treatment

Yoon, Myonggeun,Shin, Dongho,Kwak, Jungwon,Park, Soah,Lim, Young Kyung,Kim, Dongwook,Park, Sung Yong,Lee, Se Byeong,Shin, Kyung Hwan,Kim, Tae Hyun,Cho, Kwan Ho Elsevier 2009 Medical dosimetry Vol.34 No.3

<P><B>Abstract</B></P><P>We compared the main characteristics of movement-induced dose reduction during photon and proton beam treatment, based on an analysis of dose-volume histograms. To simulate target movement, a target contour was delineated in a scanned phantom and displaced by 3 to 20 mm. Although the dose reductions to the target in the 2 treatment systems were similar for transverse (perpendicular to beam direction) target motion, they were completely different for longitudinal (parallel to beam direction) target motion. While both modalities showed a relationship between the degree of target shift and the reduction in dose coverage, dose reduction showed a strong directional dependence in proton beam treatment. Clinical simulation of target movement for a prostate cancer patient showed that, although coverage and conformity indices for a 6-mm lateral movement of the prostate were reduced by 9% and 16%, respectively, for proton beam treatment, they were reduced by only 1% and 7%, respectively, for photon treatment. This difference was greater for a 15-mm target movement in the lateral direction, which lowered the coverage and conformity indices by 34% and 54%, respectively, for proton beam treatment, but changed little during photon treatment. In addition, we found that the equivalent uniform dose (EUD) and homogeneity index show similar characteristics during target movement. These results suggest that movement-induced dose reduction differs significantly between photon and proton beam treatment. Attention should be paid to the target margin in proton beam treatment due to the distinct characteristics of heavy ion beams.</P>

Effect of Proton Beam Irradiation on the Regulation of Metastasis-enhancing Factors in MCF-7 Human Breast Cancer Cells

이규식,신진선,남경수 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.7

Metastasis is a major cause of poor prognosis and recurrence in cancer patients. We have previouslyreported that cancer metastasis may be prevented by proton beam irradiation via theinduction of tissue inhibitor of matrix metalloproteases-1 and -2, known as anti-metastatic factors,and the suppression of aromatase in MCF-7 human breast cancer cells. However, the prior reportdid not show the effect of proton beam irradiation on metastasis-enhancing factors. Therefore, inthis study, the effects of proton beam irradiation on the regulation of metastasis-enhancing factors,including cyclooxygenase-2 (COX-2), matrix metalloproteinase-9 (MMP-9), urokinase plasminogenactivator (uPA) and uPA receptor (uPAR), were investigated in MCF-7 human breast cancer cells. 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of COX-2, an important proteinin metastasis and tumor growth in breast cancer, was down-regulated in a dose-dependent mannerin MCF-7 human breast cancer cells irradiated by a proton beam. Proton beam irradiation alsodecreased MMP-9 activity and expression induced by TPA. Furthermore, proton beam irradiationdose-dependently inhibited uPA and uPA receptor (uPAR) expression. In conclusion, the presentinvestigation demonstrated that TPA-induced metastatic activity in MCF-7 human breast cancercells is effectively lessened by proton beam irradiation via the reversal of COX-2, MMP-9, uPA anduPAR expressions and MMP-9 activity