Heavy Ion Medical Accelerator Research Articles

Water radiolysis with heavy ions of energies up to 28 GeV. : 1. Measurements of primary g values as track segment yields

Water radiolysis has been investigated with heavy ions having energies up to 28 GeV provided from the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). Beams of 4He 2+, 12C 6+, 20Ne 10+, 28Si 14+, 40Ar 18+ and 56Fe 26+ with respective energies of 150, 400, 400, 490, 500 and 500 MeV/ u corresponding LET values of 2.2, 13, 30, 54, 92 and 183 eV/nm, respectively, were taken for the irradiation. The LET changes in sample solutions can be neglected due to their high energies for the irradiation of 1-cm cells. Primary g values have been determined for three important products, hydrated electron (e − aq), hydroxyl radical (·OH), and hydrogen peroxide (H 2O 2) as track segment yields (differential yields) under the conditions of neutral pH. With increasing LET, the g values of e − aq and ·OH decrease from 2.4 and 2.6 in 4He 2+ radiolysis to 0.9 and 1.1 (100 eV) −1 in 56Fe 26+ radiolysis, respectively. It was also found that the primary g value of e − aq is smaller than that of ·OH for any type of ion beam. For the 12C 6+ beam, other energies such as 290, 220, 135 MeV/ u were taken for the irradiation to investigate the effects of type or atomic number of ions on the measured yields. Furthermore, effects of dissolved oxygen on enhancement of H 2O 2 production have also been investigated with aerated NaNO 3 solutions. The presence of dissolved oxygen caused 15–35% enhancement in H 2O 2 yields for all beams. In addition, the results of the present work were compared with reported track segment yields.

Microdosimetric study for secondary neutrons in phantom produced by a carbon beam

Absorbed doses from main charged‐particle beams and charged‐particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; microdosimetric distributions of secondary neutrons produced by carbon beams have been measured by using a tissue equivalent proportional counter at the Heavy Ion Medical Accelerator in Chiba, Japan at the National Institute of Radiological Sciences. The microdosimetric distributions of the secondary neutron were measured on the distal and lateral faces of a body‐simulated acrylic phantom . To confirm the dose measurements, the neutron energy spectra produced by incident carbon beams in the acrylic phantom were simulated by the particle and heavy ion transport code system. The absorbed doses obtained by multiplying the simulated neutron energy spectra with the kerma factor calculated by MCNPX agree with the corresponding experimental data fairly well. Downstream of the Bragg peak, the ratio of the neutron dose to the carbon dose at the Bragg peak was found to be a maximum of and the ratio of neutron dose was a maximum of at a lateral face of the acrylic phantom. The ratios of neutrons to charged particle fragments were 11% to 89% in the absorbed doses at the lateral and the distal faces of the acrylic phantom. We can conclude that the treatment dose will not induce serious secondary neutron effects at distances greater than from the Bragg peak in carbon particle therapy.

High Relative Biologic Effectiveness of Carbon Ion Radiation on Induction of Rat Mammary Carcinoma and its Lack of H- ras and Tp53 Mutations

The high relative biologic effectiveness (RBE) of high-linear energy transfer (LET) heavy-ion radiation has enabled powerful radiotherapy. The potential risk of later onset of secondary cancers, however, has not been adequately studied. We undertook the present study to clarify the RBE of therapeutic carbon ion radiation and molecular changes that occur in the rat mammary cancer model. We observed 7-8-week-old rats (ACI, F344, Wistar, and Sprague-Dawley) until 1 year of age after irradiation (0.05-2 Gy) with either 290 MeV/u carbon ions with a spread out Bragg peak (LET 40-90 keV/mum) generated from the Heavy-Ion Medical Accelerator in Chiba or (137)Cs gamma-rays. Carbon ions significantly induced mammary carcinomas in Sprague-Dawley rats but less so in other strains. The dose-effect relationship for carcinoma incidence in the Sprague-Dawley rats was concave downward, providing an RBE of 2 at a typical therapeutic dose per fraction. In contrast, approximately 10 should be considered for radiation protection at low doses. Immunohistochemically, 14 of 18 carcinomas were positive for estrogen receptor alpha. All carcinomas examined were free of common H-ras and Tp53 mutations. Importantly, lung metastasis (7%) was characteristic of carbon ion-irradiated rats. We found clear genetic variability in the susceptibility to carbon ion-induced mammary carcinomas. The high RBE for carbon ion radiation further supports the importance of precise dose localization in radiotherapy. Common point mutations in H-ras and Tp53 were not involved in carbon ion induction of rat mammary carcinomas.

Quantification of β+ activity generated by hard photons by means of PET

Positron emission tomography (PET) as a method for quality assurance in radiotherapy is well investigated in the case of therapy with carbon ion beams and successfully applied at the Heavy Ion Medical Accelerator at Chiba (HIMAC), Japan, and the Gesellschaft für Schwerionenforschung (GSI), Germany. By measuring the β+ activity distribution during the irradiation (in-beam PET), valuable information on the precision of the dose deposition can be obtained. To extend this efficient technique to other radiation treatment modalities may be worthwhile. For example, since positron emitters are generated by high-energy photons with energies above 20 MeV due to (γ, n) reactions (predominantly 11C and 15O in tissue), in-beam PET seems to be feasible for radiation therapy with high-energy photons as also shown in Geant4 simulations. Quantitative results on the activation of tissue-equivalent materials at hard photon beams were obtained by performing off-beam PET experiments. Homogeneous PMMA phantoms as well as inhomogeneous phantoms were irradiated with high-energy bremsstrahlung. After the irradiation the distributions of the generated positron emitters in the phantoms were measured using a conventional PET scanner. Furthermore, the depth–dose distributions were determined by means of optically stimulated luminescence detectors. In the experiments an activity per dose comparable to that produced in a typical patient irradiation with carbon ions could be achieved for 34 MV bremsstrahlung. In addition, a high contrast in the PET images for materials with different density and stoichiometry could be detected. Thus, further research concerning the development of in-beam PET seems to be worthwhile.

The Zero-Degree Detector system for fragmentation studies

The measurement of nuclear fragmentation cross-sections requires the detection and identification of individual projectile fragments. If light and heavy fragments are recorded in the same detector, it may be impossible to distinguish the signal from the light fragment. To overcome this problem, we have developed the Zero-degree Detector System (ZDDS). The ZDDS enables the measurement of cross-sections for light fragment production by using pixelated detectors to separately measure the signals of each fragment. The system has been used to measure the fragmentation of beams as heavy as Fe at the NASA Space Radiation Laboratory at Brookhaven National Laboratory and the Heavy Ion Medical Accelerator in Chiba, Japan.

Design study of a raster scanning system for moving target irradiation in heavy‐ion radiotherapy

A project to construct a new treatment facility as an extension of the existing heavy-ion medical accelerator in chiba (HIMAC) facility has been initiated for further development of carbon-ion therapy. The greatest challenge of this project is to realize treatment of a moving target by scanning irradiation. For this purpose, we decided to combine the rescanning technique and the gated irradiation method. To determine how to avoid hot and/or cold spots by the relatively large number of rescannings within an acceptable irradiation time, we have studied the scanning strategy, scanning magnets and their control, and beam intensity dynamic control. We have designed a raster scanning system and carried out a simulation of irradiating moving targets. The result shows the possibility of practical realization of moving target irradiation with pencil beam scanning. We describe the present status of our design study of the raster scanning system for the HIMAC new treatment facility.

Performance of a compact injector for heavy-ion medical accelerators

A compact injector, designed for a heavy-ion medical accelerator complex, was constructed. It consists of an Electron-Cyclotron-Resonance Ion-Source (ECRIS) and two linacs, which are a Radio-Frequency-Quadrupole linac and an Interdigital H-mode Drift-Tube-Linac (IH-DTL) having the same operating frequency of 200 MHz. For beam focusing of the IH-DTL, the method of Alternating-Phase-Focusing (APF) was employed. The compact injector can accelerate heavy ions having a charge-to-mass ratio of q m = 1 3 up to 4.0 MeV / u . Use of the APF IH-DTL and operating frequency of 200 MHz allowed us to design compact linacs; the total length of the two linacs is less than 6 m. Beam-acceleration tests of the compact injector system were performed. The measured intensity of accelerated C 4 + 12 beams with the compact injector was 380 e μ A . Beam transmission of the APF IH-DTL was estimated to be as high as 96%, which is comparable to the value calculated by a simulation code. Transverse phase-space and energy distributions of accelerated beams were measured and compared with those calculated by the simulation code, and we found that they were agreed well with each other.

Effects of prenatal irradiation with an accelerated heavy-ion beam on postnatal development in rats: II. Further study on neurophysiologic alterations

Organogenesis is a highly radiosensitive period, study of prenatal exposure to high LET heavy ion beams on postnatal development is important for clarifying the radiation risk in space and promoting the evidence-based mechanism research. The effects from heavy ion irradiations are not well studied as those for low LET radiations such as X-rays in this field, even the ground-based investigations remain to be addressed. Using the Heavy Ion Medical Accelerator in Chiba (HIMAC) and Wistar rats, postnatal neurophysiological development in offspring was investigated following exposure of pregnant rats to accelerated neon-ion beams with a LET value of about 30 keV/μm at a dose range from 0.1 to 2.0 Gy on the 15th day of gestation. The age for appearance of four physiologic markers and attainment of five neonatal reflexes, and gain in body weight were monitored. Male offspring were evaluated as young adults using two behavioral tests including open field and hole-board dipping tests. The effects of X-rays at 200 kVp measured for the same biological end points were studied for comparison. For most of the endpoints at early age, significant neurophysiological alteration was observed even in offspring receiving 0.1 Gy of accelerated neon ions but not X-rays. All offspring receiving 2.0 Gy of accelerated neon ions died prior to weaning. Offspring prenatally irradiated with neon ions generally showed higher incidences of prenatal death, increased preweaning mortality, markedly delayed accomplishment in physiological markers and reflexes, significantly lower body weight and reduced ratios of main organ weight to body weight, and altered behavior compared to those exposed to X-rays at doses of 0.1–1.5 Gy. These findings indicate that irradiations with neon ions at 0.1–1.5 Gy on day 15 of gestation caused varied developmental alterations in offspring, and efficient dose leading to the detrimental effects seemed to be lower than that of X-rays.

Effects of prenatal irradiation with accelerated heavy-ion beams on postnatal development in rats: III. Testicular development and breeding activity

With a significant increase in human activities dealing with space missions, potential teratogenic effects on the mammalian reproductive system from prenatal exposure to space radiation have become a hot topic that needs to be addressed. However, even for the ground experiments, such effects from exposure to high LET ionizing radiation are not as well studied as those for low LET ionizing radiations such as X-rays. Using the Heavy-Ion Medical Accelerator in Chiba (HIMAC) and Wistar rats, effects on gonads in prenatal male fetuses, on postnatal testicular development and on breeding activity of male offspring were studied following exposure of the pregnant animals to either accelerated carbon-ion beams with a LET value of about 13 keV/μm or neon-ion beams with a LET value of about 30 keV/μm at a dose range from 0.1 to 2.0 Gy on gestation day 15. The effects of X-rays at 200 kVp estimated for the same biological end points were studied for comparison. A significantly dose-dependent increase of apoptosis in gonocytes appeared 6 h after irradiations with a dose of 0.5 Gy or more. Measured delayed testis descent and malformed testicular seminiferous tubules were observed to be significantly different from the control animals at a dose of 0.5 Gy. These effects are observed to be dose- and LET-dependent. Markedly reduced testicular weight and testicular weight to body weight ratio were scored at postnatal day 30 even in the offspring that were prenatally irradiated with neon-ions at a dose of 0.1 Gy. A dose of 0.5 Gy from neon-ion beams induced a marked decrease in breeding activity in the prenatally irradiated male rats, while for the carbon-ion beams or X-rays, the significantly reduced breeding activity was observed only when the prenatal dose was at 1.0 Gy or more. These findings indicated that prenatal irradiations with heavy-ion beams on gestation day 15 generally induced markedly detrimental effects on prenatal gonads, postnatal testicular development and male breeding activity in rats, which seemed to be a dose and LET-related event.

The PCC assay can be used to predict radiosensitivity in biopsy cultures irradiated with different types of radiation

The aim of this study was to identify potential biomarkers for radiosensitivity using the relationship between cell killing and the yield of excess chromatin fragments detected with the premature chromosome condensation (PCC) technique. This method was applied to primary cultured cells obtained from biopsies from patients. Six primary culture biopsies were obtained from 6 patients with carcinoma of the cervix before starting radiotherapy. The cultures were irradiated with two different LET carbon-ion beams (LET = 13 keV/microm, 77.1+/-2.8 keV/microm) and 200 kV X-rays. The carbon-ion beams were produced by Heavy Ion Medical Accelerator in Chiba (HIMAC). PCC was performed using the polyethylene glycol-mediated cell fusion technique. The yield of excess chromatin fragments were measured by counting the number of unrejoined chromatin fragments detected with the PCC technique after a 24-h post-irradiation incubation period. Obtained results indicated that cultures which were more sensitive to killing were also more susceptible to the induction of excess chromatin fragments. Furthermore there was a good correlation between cell killing and excess chromatin fragments among the 6 cell cultures examined. There is also evidence that the induction of excess chromatin fragments increased with increasing LET as well as cell-killing effect in the same cell culture. The data reported here support the idea that the yield of excess chromatin fragments detected with the PCC technique might be useful for predicting the radiosensitivity of cells contained in tumor tissue, and to predict responses to different radiation types.

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The purpose of this study was to identify molecular mechanism induced by carbon ion radiotherapy in order to provide information on potential targets for prediction of its effectiveness. Murine squamous cell carcinomas, NR-S1 (resistant to gamma-irradiation), and SCCVII (sensitive), were transplanted in hind legs of C3H/He male mice and established solid tumors (7.5–8.5 mm in diameter) were locally irradiated with carbon ion beam at 30Gy. Carbon-12 ions were accelerated by the Heavy Ion Medical Accelerator in Chiba or HIMAC synchrotron up to 290 MeV/u with a dose rate of approximately 3 Gy /min. Tumor growth delay (TGD) time, reduction rate of tumor, and recurrence rate of tumor were investigated as parameters of radiosensitivity of tumors. The mice were sacrificed and immediately dissected before irradiation and after different time points, such as 6,12,18h, 1, 3, 5, 7, 10, 15, 20 days after irradiation or recurrence for transcriptome assays and pathological investigation. Expression analyses were performed using single-color analysis microarrays consisting of 55k genes. Principal Compornent Analysis (PCA) was used to investigate similarity of comprehensive overview of the changes in gene expression between expression profiles of two tumors. Analysis of variance (ANOVA) was applied to the intensity of each tumor at different time point to evaluate significant differences. TGD time of NR-S1 and SCCVII was 30 days and 56 days, reduction rate of NR-S1 and SCCVII was 40% and 100%, and recurrence rate of NR-S1 and SCCVII was 75% and 50%, respectively.PCA showed that all expression profiles of NR-S1 were identified as a group, while those of SCCVII were identified as another group. Recurred tumors showed different profiles from non-irradiation control tumors. We detected genes, whose expressions were significantly up-regulated or down regulated at each time point after carbon-irradiation (p value< 0.0001). At 6 hours after irradiation, fourteen genes, which were related with cell cycle regulation, were differentially expressed in both tumors. Eleven genes, which were related with inflammation or extracellular matrix, were up-regulated at 6 hours in both tumors, however, their expression changes on time-course were different. Pathological specimen showed duplet cells in both tumors 1 day after irradiation and continuous infiltration of inflammatory cells in SCCVII. Tumor growth assays revealed that two murine tumors, which have different radiosensitivity to gamma irradiation, kept their intrinsic radiosensitivity to carbon-ion irradiation. Transcriptional profiling of two tumors identified a number of carbon-ion irradiation response genes in murine tumors. We have also identified genes as being candidates for predictive markers of radiosensitivity to carbon-ion therapy.

Commissioning of a conformal irradiation system for heavy-ion radiotherapy using a layer-stacking method

The commissioning of conformal radiotherapy system using heavy-ion beams at the Heavy Ion Medical Accelerator in Chiba (HIMAC) is described in detail. The system at HIMAC was upgraded for a clinical trial using a new technique: large spot uniform scanning with conformal layer stacking. The system was developed to localize the irradiation dose to the target volume more effectively than with the old system. With the present passive irradiation method using a ridge filter, a scatterer, a pair of wobbler magnets, and a multileaf collimator, the width of the spread-out Bragg peak (SOBP) in the radiation field could not be changed. With dynamic control of the beam-modifying devices during irradiation, a more conformal radiotherapy could be achieved. In order to safely perform treatments with this conformal therapy, the moving devices should be watched during irradiation and the synchronousness among the devices should be verified. This system, which has to be safe for patient irradiations, was constructed and tested for safety and for the quality of the dose localization realized. Through these commissioning tests, we were successfully able to prepare the conformal technique using layer stacking for patients. Subsequent to commissioning the technique has been applied to patients in clinical trials.

Synchrotron magnet power supply network with normal and common modes including noise filtering

We study theoretical aspects of power supply network for synchrotron magnets, particularly the Heavy Ion Medical Accelerator Complex (HIMAC) system that operates with good stability. We introduce a simplified electric circuit model, which uses a thyristor rectifier power supply, a noise filter, and synchrotron magnets, to introduce the concept of the normal and the common modes. The normal and common modes become decoupled when all the electric loads are placed symmetrically around the ground line for a three line circuit system. This construction makes the normal mode the dominant control of the magnetic fields of the accelerator magnets. It is then found that the connection of the ground (common) line to the middle point of the thyristor power supply is essential to make the common mode stable. These two arrangements can remove the noise at high frequency in the normal mode by the noise filter and hence the noise in the magnetic fields, resulting in stable performance of the synchrotron network.

The efficiency of various thermoluminescence dosemeter types to heavy ions

Dose verification in heavy-ion beams using passive dosemeter systems, e.g. thermoluminescence dosemeters (TLDs), is crucial due to the changing efficiency of the dosemeters for different ion species and linear energy transfer (LET) values. This behaviour leads to a falsification of absorbed dose that can be significant for many applications, e.g. in space or radiotherapeutic dosimetry. TLDs can only be established as a 'reference' system in heavy-ion beams or other radiation fields if the efficiency functions for all contributing ion species and LET values are provided. In the framework of a research project of the Atominstitute of the Austrian Universities irradiations with various ions were performed in the years 2001-2003 at the Heavy Ion Medical Accelerator (HIMAC) of the National Institute for Radiological Sciences (NIRS) in Chiba, Japan. Efficiency values were recorded in dependence on ion species and LET in a range from 2 to 400 keV microm(-1). The efficiencies of five different commercially available TLD materials namely TLD 600, TLD 700, TLD 700H, TLD 300 and TLD 200 were investigated.

Efficiency-corrected dose verification with thermoluminescence dosemeters in heavy-ion beams

One of the most essential difficulties in heavy-ion dosimetry by means of thermoluminescence dosemeters (TLDs)--often seen as a serious disadvantage of TLD utilisation--regards the changing TL-efficiency with increasing linear energy transfer (LET) of the particle. This behaviour leads to a falsification of absorbed dose that can be significant for many applications, e.g. in space or radiotherapeutic dosimetry. The high-temperature TL emission of LiF:Mg,Ti TL detectors can be exploited to obtain information about the LET of the heavy-ion radiation field under study. The high-temperature ratio (HTR) is used as a parameter to determine average LET. To correct the absorbed dose according to the TL-efficiency, the detailed dependence of HTR- and TL-efficiency on LET was recorded. These investigations were accomplished at the Heavy Ion Medical Accelerator (HIMAC) in Chiba, Japan, with a variety of high-energy ion beams (helium, carbon, neon, silicon and iron) ranging in LET from 2.2 to 393 keV microm(-1). The obtained relationships HTR vs. LET and TL-efficiency vs. LET were combined into a TL efficieny vs. HTR relationship. This enables correction of the absorbed dose (HTR-B method). The methodology is demonstrated by means of TLD 700 ((7)LiF:Mg,Ti) measurements in carbon beams of 290 and 400 MeV n(-1) available from HIMAC.

The intercomparison of cosmic rays with heavy ion beams at NIRS (ICCHIBAN) project

The ICCHIBAN-2 experiment, the first dedicated to the ground-based intercomparison of passive space dosemeters, was carried out between 23 May and 28 May 2002 at the National Institute of Radiological Sciences in Chiba, Japan. The primary objective of the ICCHIBAN-2 experiment was to intercompare the response of passive dosemeters used in space crew dosimetry to monoenergetic heavy ions of charge and energy spanning a significant portion of the galactic cosmic ray (GCR) spectrum. During the ICCHIBAN-2 experiment, dosemeters from 12 different laboratories in 9 countries were irradiated under identical conditions to heavy ion beams of 150 MeV n(-1) (4)He, 400 MeV n(-1) (12)C, 490 MeV n(-1) (28)Si and 500 MeV n(-1) (56)Fe at the NIRS Heavy Ion Medical Accelerator.

LET dependence of bubble detector response to heavy ions

A series of experiments have been recently performed at the Heavy Ion Medical Accelerator in Chiba (HIMAC) laboratory to study the response of bubble detectors to high-mass high-energy (HZE) particles. The motivation for this study was to improve our ability to interpret measurements of neutron energy spectra in space. A recent analysis showed that emulsions of light halocarbons display common properties when they are characterised by a quantity called 'reduced superheat'. This quantity evolved from the examination of neutron and gamma responses of many types of detectors. In this study, we describe direct irradiations with N, Ar and Kr charged particles at HIMAC. It was observed that when the linear energy transfer (LET) corresponding to bubble formation was plotted vs. reduced superheat, different curves were obtained for a particular ion for detectors at different temperatures. Different curves were also obtained when data from different ions were plotted. These results confirm that bubble nucleation is not a simple function of particle LET and that an analysis based on track-structure appears warranted.

Heavy-ion cancer therapy

The HIMAC Heavy-Ion Medical Accelerator in Chiba was completed in 1993, and clinical trials of particle radiotherapy for cancer were started using carbon beams accelerated by HIMAC in 1994. Since then, about 2200 patients have been treated in the carbon radiotherapy up to the end of February 2005. A heavy-ion beam generates a Bragg peak in a medium, and it provides biological effects of high RBE and low OER in the Bragg peak region. In heavy-ion radiotherapy, therefore, the beam delivers a high radiation dose to a target volume highly locally. These are excellent advantages for radiotherapy over the case of X-rays. The clinical trials have proved that carbon radiotherapy brings various good results.

In-beam PET at high-energy photon beams: a feasibility study

For radiation therapy with carbon ion beams, either for the stable isotope 12C or for the radioactive one 11C, it has been demonstrated that the β+-activity distribution created or deposited, respectively, within the irradiated volume can be visualized by means of positron emission tomography (PET). The PET images provide valuable information for quality assurance and precision improvement of ion therapy. Dedicated PET scanners have been integrated into treatment sites at the Heavy Ion Medical Accelerator at Chiba (HIMAC), Japan, and the Gesellschaft für Schwerionenforschung (GSI), Germany, to make PET imaging feasible during therapeutic irradiation (in-beam PET). A similar technique may be worthwhile for radiotherapy with high-energy bremsstrahlung. In addition to monitoring the dose delivery process which in-beam PET has been primarily developed for, it may be expected that radiation response of tissue can be detected by means of in-beam PET. We investigate the applicability of PET for treatment control in the case of using bremsstrahlung spectra produced by 15–50 MeV electrons. Target volume activation due to (γ, n) reactions at energies above 20 MeV yields moderate β+-activity levels, which can be employed for imaging. The radiation from positrons produced by pair production is not presently usable because the detectors are overloaded due to the low duty factor of medical electron linear accelerators. However, the degradation of images caused by positron motion between creation and annihilation seems to be tolerable.

A method of tagging the nuclear fragmentation event induced by /sup 11/C for cancer therapy

Heavy ion cancer therapy using energetic /sup 12/C ions has been carried out successfully at the Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The method has advantages over traditional radiation therapy using an energetic photon beam in two respects: the dose concentration owing to the Bragg peak and high biological effects. The development of a cancer therapy using /sup 11/C ions is also currently underway at HIMAC, however, there remains the problem of beam attenuation due to nuclear fragmentation reactions in the body of the patient; this requires modification of the dose calculation for the therapy. To the best of our knowledge, no research on /sup 11/C-induced nuclear fragmentation reactions has yet been published. We propose a method of identifying the nuclear fragmentation reaction event induced by the carbon beams using a total-absorption-type target detector, that plays the role of a human phantom, and a system of plastic scintillation counters surrounding the phantom. We have carried out measurements for the carbon beams with the detector system. A portion of the beam energy is lost as escaping fragment particles from the phantom, leading to a decrease in beam intensity. We were able to successfully detect nuclear reaction events on an event-by-event basis.