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Purpose: The uncertainty of target location during prostate cancer radiotherapy plays an important role in accurate dose delivery and radiation toxicity in adjacent organs. This study analyzed displacement correlations between the prostate and pelvic floor., Methods and Materials: We retrospectively analyzed registration results from 467 daily cone-beam computed tomography (CT) in 12 patients with prostate cancer who received radiation therapy. We analyzed prostate displacement and the pelvic floor relative to the pelvic bone's anatomy in the translational and rotational directions and identified statistical correlations., Results: The systematic (Σ) and random (σ) displacements of the prostate in the three translational directions, anterior-posterior (AP), superior-inferior (SI), and right-left (RL), were 1.49 ± 1.45, 2.10 ± 1.40, and 0.24 ± 0.53 mm, respectively, and in the rotational directions of the pitch, roll, and yaw were 2.10 ± 2.02°, 0.42 ± 0.74°, and 0.42 ± 0.64°, respectively. The pelvic floor displacements were 2.37 ± 1.96, 2.71 ± 2.28, and 0.47 ± 0.84 mm in the AP, SI, and RL directions, respectively, and 0.93 ± 1.49°, 0.98 ± 1.28 °, and 0.87 ± 0.94° in the pitch, roll, and yaw directions, respectively. Additionally, there were statistically significant correlations between the displacement of the prostate and pelvic floor in the AP and SI directions, with correlation coefficients (r) of 0.74 (p < 0.001) and 0.69 (p < 0.001), respectively., Conclusions: The movement of the pelvic floor may be an important factor that causes prostate displacement, affecting the accuracy of radiotherapy. Therefore, it is necessary to take appropriate measures to ensure that the pelvic floor muscle tension is as consistent as possible in the treatment' CT scan and daily treatment., (© 2024 The Author(s). The Prostate published by Wiley Periodicals LLC.)

Background: This study aimed to evaluate the clinical acceptability of rotational gantry-based single-position carbon-ion radiotherapy (CIRT) to reduce the gastrointestinal (GI) dose in pancreatic cancer. We also evaluated the usefulness of the deformable image registration (DIR)-based dosimetry method for CIRT., Material and Methods: Fifteen patients with pancreatic cancer were analyzed. The treatment plans were developed for four beam angles in the supine (SP plan) and prone (PR plan) positions. In the case of using multiple positions, the treatment plan was created with two angles for each of the supine and prone position (SP + PR plan). Dose evaluation for multiple positions was performed in two ways: by directly adding the values of the DVH parameters for each position treatment plan (DVH sum), and by calculating the DVH parameters from the accumulative dose distribution created using DIR (DIR sum). The D 2cc and D 6cc of the stomach and duodenum were recorded for each treatment plan and dosimetry method and compared., Results: There were no significant differences among any of the treatment planning and dosimetry methods (p > 0.05). The DVH parameters for the stomach and duodenum were higher in the PR plan and SP plan, respectively, and DVH sum tended to be between the SP and PR plans. DVH sum and DIR sum, DVH sum tended to be higher for D 2cc and DIR sum tended to be higher for D 6cc ., Conclusion: There were no significant differences in the GI dose, which suggests that treatment with a simple workflow performed in one position should be clinically acceptable. In CIRT, DIR-based dosimetry should be carefully considered because of the potential for increased uncertainty due to the steep dose distributions., (© 2024 The Authors. Journal of Applied Clinical Medical Physics is published by Wiley Periodicals, Inc. on behalf of The American Association of Physicists in Medicine.)

Purpose: We performed computed tomography (CT)-stopping power ratio (SPR) calibration in a carbon-ion therapy facility and evaluated SPR estimation accuracy., Materials and Methods: A polybinary tissue model method was used for the calibration of CT numbers and SPR. As a verification by dose calculation, we created a virtual phantom to which the CT-SPR calibration table was applied. Then, SPR was calculated from the change in the range of the treatment planning beam when changing to 19 different CT numbers, and the accuracy of the treatment planning system (TPS) calculation of SPR values from the CT-SPR calibration table was validated. As a verification by measurement, 5 materials (water, milk, olive oil, ethanol, 40% K 2 HPO 4 ) were placed in a container, and the SPR was obtained by measurement from the change in the range of the beam that passed through the materials., Results: The results of the dose calculations of the TPS showed that the results agreed within 1% for the lower CT numbers up to 1000 HU, but there was a difference of 3.0% in the higher CT number volume. The difference between the SPR calculated by TPS and the SPR caused by the difference in the energy of the incident particles agreed within 0.51%. The accuracy of SPR estimation was measured, and the error was within 2% for all materials tested., Conclusion: These results indicate that the SPR estimation errors are within the range of errors that can be expected in particle therapy. From commissioning and verification results, the CT-SPR calibration table obtained during this commissioning process is clinically applicable., (© 2024 The Author(s).)

Background: Faced with the increase in the number of chronic diseases with the aging of the population, and with the observation of the insufficiency of therapeutic control, a new need has emerged, that of having a patient as a partner in care., Methods: This study is a randomized controlled trial. Patients with coronary heart disease will be recruited from one clinical site and randomly assigned into two groups: the intervention group and the control group. All participants will be followed up for a total of one year (with three-time points for data collection). Patients who are assigned to the intervention group will receive therapeutic education at first. The digital platform will then allow healthcare providers to accompany them outside the hospital walls. The primary outcome is the incidence of major cardiovascular events within one year of discharge. Main secondary outcomes include changes in health behaviors, medication adherence, and quality of life score. The digital platform is a multi-professional telemonitoring platform that allows care teams to accompany the patient outside the hospital walls. It allows the collection and transmits information from the patient's home to the therapeutic education team. All data will be secured at a certified host. The patient application provides data on compliance, adherence to physical activity (number of steps taken per day), adequate diet (weight gain, food consumed during the meal, compliance with low-salt or salt-free diet, diabetic diet), smoking cessation, as well as medication adherence. Access to educational tools (digital media) is provided to all initial program participants. These tools will be updated annually by the rehabilitation team on the recommendations. The platform also offers the possibility of organizing an individual or group remote educational session (videoconference modules allowing group and individual sessions), a secure integrated caregiver-patient messaging system. The control group will receive the usual controls at the hospital., Discussion: To offer a complete solution of care to our patients, we have thought of setting up a digital platform that aims to monitor the patient and strengthen their abilities to manage their condition daily. This pilot experience could be generalized to several services and disciplines. It could be used in several research works., Trial Registration: Trial registered with the Pan African Clinical Trial Registry (PACTR202307694422939). URL: https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=24247., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ghali et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: The aim of this study was to determine the genuine prognostic relevance of primary tumor sidedness (PTS) in patients with early-stage colorectal cancer (CRC)., Background: The prognostic relevance of PTS in early-stage CRC remains a topic of debate. Several large epidemiological studies investigated survival only and did not consider the risk of recurrence so far., Methods: Patients with stage II/III adenocarcinoma of the colon and upper rectum from 4 randomized controlled trials were analyzed. Survival outcomes were compared according to the tumor location: right-sided (cecum to transverse colon) or left-sided (descending colon to upper rectum)., Results: A total of 4113 patients were divided into a right-sided group (N=1349) and a left-sided group (N=2764). Relapse-free survival after primary surgery was not associated with PTS in all patients and each stage [hazard ratio (HR) adjusted =1.024 (95% CI: 0.886-1.183) in all patients; 1.327 (0.852-2.067) in stage II; and 0.990 (0.850-1.154) in stage III]. Also, overall survival after primary surgery was not associated with PTS in all patients and each stage [HR adjusted =0.879 (95% CI: 0.726-1.064) in all patients; 1.517 (0.738-3.115) in stage II; and 0.840 (0.689-1.024) in stage III]. In total, 795 patients (right-sided, N=257; left-sided, N=538) developed recurrence after primary surgery. PTS was significantly associated with overall survival after recurrence (HR adjusted =0.773, 95% CI: 0.627-0.954)., Conclusions: PTS had no impact on the risk of recurrence for stage II/III CRC. Treatment stratification based on PTS is unnecessary for early-stage CRC., Competing Interests: Y.K. received consulting or advisory role from Covidien; honoraria from Chugai Pharma, Ethicon, Covidien, and Intuitive Surgical. T.H. received honoraria from Chugai Pharma, Merck Serono, Takeda, Taiho Pharmaceutical, Ono Pharmaceutical, Yakult Pharmaceutical, Lilly, Bristol-Myers Squibb Japan, Bayer, and Daiichi Sankyo/UCB Japan; research funding from Taiho Pharmaceutical, Ono Pharmaceutical, Chugai Pharma, BeiGene, Astellas Pharma, AstraZeneca, and Pfizer. Y.S. received honoraria from Ono Pharmaceutical, Novartis, Yakult Honsha, and Daiichi Sankyo/UCB Japan. M.O. received speakers’ bureau from Chugai Pharma: research funding from Taiho Pharmaceutical. J.W. received speakers’ bureau from Covidien, Johnson & Johnson/Janssen, and Lilly Japan; research funding from Medtronic, and TERUMO. T.K. received honoraria from Ethicon: research funding from Chugai Pharma, and Taiho Pharmaceutical. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Chest wall postmastectomy radiation therapy (PMRT) should consider the effects of chest wall respiratory motion. The purpose of this study is to evaluate the effectiveness of robustness planning intensity modulated radiation therapy (IMRT) for respiratory movement, considering respiratory motion as a setup error., Material and Methods: This study analyzed 20 patients who underwent PMRT (10 left and 10 right chest walls). The following three treatment plans were created for each case and compared. The treatment plans are a planning target volume (PTV) plan (PP) that covers the PTV within the body contour with the prescribed dose, a virtual bolus plan (VP) that sets a virtual bolus in contact with the body surface and prescribing the dose that includes the PTV outside the body contour, and a robust plan (RP) that considers respiratory movement as a setup uncertainty and performs robust optimization. The isocenter was shifted to reproduce the chest wall motion pattern and the doses were recalculated for comparison for each treatment plan., Result: No significant difference was found between the PP and the RP in terms of the tumor dose in the treatment plan. In contrast, VP had 3.5% higher PTV Dmax and 5.5% lower PTV V95% than RP (p < 0.001). The RP demonstrated significantly higher lung V20Gy and Dmean by 1.4% and 0.4 Gy, respectively, than the PP. The RP showed smaller changes in dose distribution affected by chest wall motion and significantly higher tumor dose coverage than the PP and VP., Conclusion: We revealed that the RP demonstrated comparable tumor doses to the PP in treatment planning and was robust for respiratory motion compared to both the PP and the VP. However, the organ at risk dose in the RP was slightly higher; therefore, its clinical use should be carefully considered., (© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals LLC on behalf of American Association of Physicists in Medicine.)

The errors on the stopping power ratio (SPR) of mouthpiece samples from ERKODENT were evaluated. Erkoflex and Erkoloc-pro from ERKODENT and samples that combined Erkoflex and Erkoloc-pro were computed tomography (CT)-scanned using head and neck (HN) protocol at the East Japan Heavy Ion Center (EJHIC), and the values were averaged to obtain the CT number. The integral depth dose of the Bragg curve with and without these samples was measured for 292.1, 180.9, and 118.8 MeV/u of the carbon-ion pencil beam using an ionization chamber with concentric electrodes at the horizontal port of the EJHIC. The average value of the water equivalent length (WEL) of each sample was obtained from the difference between the range of the Bragg curve and the thickness of the sample. To calculate the difference between the theoretical and measured values, the theoretical CT number and SPR value of the sample were calculated using the stoichiometric calibration method. Compared with the Hounsfield unit (HU)-SPR calibration curve used at the EJHIC, the SPR error on each measured and theoretical value was calculated. The WEL value of the mouthpiece sample had an error of approximately 3.5% in the HU-SPR calibration curve. From this error, it was evaluated that for a mouthpiece with a thickness of 10 mm, a beam range error of approximately 0.4 mm can occur, and for a mouthpiece with a thickness of 30 mm, a beam range error of approximately 1 mm can occur. For a beam passing through the mouthpiece in HN treatment, it would be practical to consider a mouthpiece margin of 1 mm to avoid beam range errors if ions pass through the mouthpiece., (© 2023 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

This study aimed to develop a new method to quantitatively analyze body shape changes in patients during radiotherapy without additional radiation exposure using an optical surface tracking system. This method's accuracy was evaluated using a cubic phantom with a known shift. Surface images of three-dimensionally printed phantoms, which simulated the head and neck shapes of real patients before and after treatment, were used to create a deformation surface area histogram. The near-maximum deformation value covering an area of 2 cm 2 in the surface image (Def-2cm 2 ) was calculated. A volumetric modulated arc therapy (VMAT) plan was also created on the pre-treatment phantom, and the dose distribution was recalculated on the post-treatment phantom to compare the dose indices. Surface images of four patients were analyzed to evaluate Def-2cm 2 and examine whether this method can be used in clinical cases. Experiments with the cubic phantom resulted in a mean deformation error of 0.08 mm. With head and neck phantoms, the Def-2cm 2 value was 17.5 mm, and the dose that covered 95% of the planning target volume in the VMAT plan decreased by 11.7%, indicating that deformation of the body surface may affect the dose distribution. Although analysis of the clinical data showed no clinically relevant deformation in any of the cases, slight skin sagging and respiratory changes in the body surface were observed. The proposed method can quantitatively and accurately evaluate the deformation of a body surface. This method is expected to be used to make decisions regarding modifications to treatment plans., (© 2022. The Author(s), under exclusive licence to Japanese Society of Radiological Technology and Japan Society of Medical Physics.)

The accurate measurement of the 3D dose distribution of carbon-ion beams is essential for safe carbon-ion therapy. Although ionization chambers scanned in a water tank or air are conventionally used for this purpose, these measurement methods are time-consuming. We thus developed a rapid 3D dose-measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator with lower linear energy transfer (LET) dependence than gadolinium-based (Gd) scintillators; this tool enables the measurement of carbon-ion beams with small corrections. A ZnS scintillator sheet was placed vertical to the beam axis and installed in a shaded box. Scintillation images produced by incident carbon-ions were reflected with a mirror and captured with a charge-coupled device (CCD) camera. A 290 MeV/nucleon mono-energetic beam and spread-out Bragg peak (SOBP) carbon-ion passive beams were delivered at the Gunma University Heavy Ion Medical Center. A water tank was installed above the scintillator with the water level remotely adjusted to the measurement depth. Images were recorded at various water depths and stacked in the depth direction to create 3D scintillation images. Depth and lateral profiles were analyzed from the images. The ZnS-scintillator-measured depth profile agreed with the depth dose measured using an ionization chamber, outperforming the conventional Gd-based scintillator. Measurements were realized with smaller corrections for a carbon-ion beam with a higher LET than a proton. Lateral profiles at the entrance and the Bragg peak depths could be measured with this tool. The proposed method would make it possible to rapidly perform 3D dose-distribution measurements of carbon-ion beams with smaller quenching corrections., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

We aimed to predict the minimum distance between a tumor and the gastrointestinal (GI) tract that can satisfy the dose constraint by creating simulation plans with carbon-ion (C-ion) radiotherapy (RT) and photon RT for each case assuming insertion of virtual spacers of various thicknesses. We enrolled 55 patients with a pelvic tumor adjacent to the GI tract. Virtual spacers were defined as the overlap volume between the GI tract and the volume expanded 7-17 mm from the gross tumor volume (GTV). Simulation plans (70 Gy in 35 fractions for at least 95% of the planning target volume [PTV]) were created with the lowest possible dose to the GI tract under conditions that meet the dose constraints of the PTV. We defined the minimum thickness of virtual spacers meeting D2 cc of the GI tract <50 Gy as 'MTS'. Multiple regression was used with explanatory variables to develop a model to predict MTS. We discovered that MTSs were at most 9 mm and 13 mm for C-ion RT and photon RT plans, respectively. The volume of overlap between the GI tract and a virtual spacer of 14 mm in thickness (OV14)-PTV was found to be the most important explanatory variable in the MTS prediction equation for both C-ion and photon RT plans. Multiple R2 values for the regression model were 0.571 and 0.347 for C-ion RT and photon RT plans, respectively. In conclusion, regression equations were developed to predict MTS in C-ion RT and photon RT., (© The Author(s) 2021. Published by Oxford University Press on behalf of The Japanese Radiation Research Society and Japanese Society for Radiation Oncology.)

For the practical application of carbon-knife with fine carbon-ion beams, the quantification of the dose distribution is essential and requires a high spatial resolution. We propose a novel method to quantify dose distributions with a spatial resolution smaller than the dosimeter size. The proposed method innovates the iterative reconstruction technique. Using a diode dosimeter with a sensitive area of 1 mm 2 , two-dimensional dose-area-product (DAP) distributions were measured at a 0.1 mm step at the surface and near the Bragg peak depths for fine carbon-ion beams of ∼1 mm size at the full width at half maximum (FWHM). Then, the dose distributions were reconstructed with a spatial resolution of 0.1 × 0.1 mm 2 from the measured DAP distributions. However, an unnaturally high noise was observed in the reconstructed dose distributions, which were considered to originate from the measurement reproducibility errors of the DAP distributions estimated to be 2.5%-3%. Therefore, a low-pass filtering process was implemented to reduce the errors on the reconstructed dose distributions. The optimum cut-off frequencies of the low-pass filter were estimated depending on the amplitude of the induced noise. Using the filtering process with the obtained optimum cut-off frequency, the dose distribution was quantified with an average error of approximately 3% or less with respect to the peak value, when the actual measurement had an error of 3%. In the reconstructed dose rate distributions, a steep penumbra P 80-20 ∼ 0.2 mm was observed at the surface, and a dose rate at the center axis of ∼90 Gy s -1 and a beam size of ∼1.1 mm at FWHM near the Bragg peak were obtained. The proposed method is expected to be useful for the measurement-based determination of microbeam models for commissioning and dose distribution calculations toward carbon-knife applications.

Radiochromic films are useful as dosimeters in high-precision radiotherapy owing to their high spatial resolution. However, when a particle beam is measured using a radiochromic film, the dose cannot be estimated accurately because the film darkness varies with variations in linear energy transfer (LET). This paper proposes a novel method for estimating the LET and the dose based on the film darkness. In this method, after a high-LET particle beam, such as a carbon-ion beam, was incident on the film, the film was digitized and its net optical density was determined. Further, the non-linearity of the film response curve between the dose and the darkness, depending on LET, was used. Then, calibration curves were created using 290 MeV u -1 mono energetic carbon-ion beams. We used LETs of 20, 50, 100, and 150 keV µm -1 and a physical dose of 2-14 Gy. The calibration curves were approximated for each LET using a quadratic function. The correlations between the coefficients of the quadratic function and the LET were also obtained. To verify the proposed method, the films were irradiated under 12 different conditions corresponding to various depths and doses. Four depths of -2, -5, -10, and -20 mm with respect to the Bragg peak, and three different preset values were used for the film measurements. The films were analyzed in four groups, where each group comprised films irradiated at the same depth. The LETs obtained from the film analysis, ordered from the upstream of the beam, were 20, 41, 56, and 97 keV µm -1 , and the doses for the lowest preset value were 3.95, 4.07, 4.03, and 3.99 Gy for the four groups. The LETs obtained from the film analysis increased toward the Bragg peak, and the doses measured in the ionization chamber were almost equal to 4 Gy.

Purpose: To estimate relative biological effectiveness (RBE) ascribed to secondary fragments in a lateral distribution of carbon ion irradiation. The RBE was estimated with the microdosimetric kinetic (MK) model and measured linear energy transfer (LET) obtained with CR-39 plastic detectors., Methods: A water phantom was irradiated by a 12 C pencil beam with energy of 380 MeV/u at the Gunma University Heavy Ion Medical Center (GHMC), and CR-39 detectors were exposed to secondary fragments. Because CR-39 was insensitive to low LET, we conducted Monte Carlo simulations with Geant4 to calculate low LET particles. The spectra of low LET particles were combined with experimental spectra to calculate RBE. To estimate accuracy of RBE, we calculated RBE by changing yield of low LET particles by ± 10% and ± 40%., Results: At a small angle, maximum RBE by secondary fragments was 1.3 for 10% survival fractions. RBE values of fragments gradually decreased as the angle became larger. The shape of the LET spectra in the simulation reproduced the experimental spectra, but there was a discrepancy between the simulation and experiment for the relative yield of fragments. When the yield of low LET particles was changed by ± 40%, the change in RBE was smaller than 10%., Conclusions: An RBE of 1.3 was expected for secondary fragments emitted at a small angle. Although, we observed a discrepancy in the relative yield of secondary fragments between simulation and experiment, precision of RBE was not so sensitive to the yield of low LET particles., (© 2019 American Association of Physicists in Medicine.)

Background: Due to an aging society, patients with gastric cancer are also getting older. Although total gastrectomy should be avoided for elderly patients, laparoscopic subtotal gastrectomy(LSTG)is a technically demanding procedure. Here, we present a safe procedure of gastro-jejunostomy using the overlap method., Methods: After transection of the stomach using gastroscopy, an entry hole was created at the center of the staple line of the remnant stomach. The jejunum was anastomosed to the dorsal wall of the gastric remnant with a linear stapler, and the entry hole was closed by hand-sewn sutures. Nineteen patients with gastric cancer in the upper third of the stomach underwent LSTG using this technique, and the short-term clinical outcomes were analyzed retrospectively., Results: The median operative time was 221 minutes(143-318), and the median blood loss was 10 mL(3-100). The median postoperative hospital stay was 7 days(6-13), and there were no complications related to anastomosis., Conclusions: The short-term clinical outcomes of the laparoscopic gastro-jejunostomy using the overlap method after LSTG reveal that this technique is safe and feasible to use for improving patient outcomes.

Multiple unique environmental factors such as space radiation and microgravity (μ G ) pose a serious threat to human gene stability during space travel. Recently, we reported that simultaneous exposure of human fibroblasts to simulated μ G and radiation results in more chromosomal aberrations than in cells exposed to radiation alone. However, the mechanisms behind this remain unknown. The purpose of this study was thus to obtain comprehensive data on gene expression using a three-dimensional clinostat synchronized to a carbon (C)-ion or X-ray irradiation system. Human fibroblasts (1BR-hTERT) were maintained under standing or rotating conditions for 3 or 24 h after synchronized C-ion or X-ray irradiation at 1 Gy as part of a total culture time of 2 days. Among 57,773 genes analyzed with RNA sequencing, we focused particularly on the expression of 82 cell cycle-related genes after exposure to the radiation and simulated μ G . The expression of cell cycle-suppressing genes ( ABL1 and CDKN1A ) decreased and that of cell cycle-promoting genes ( CCNB1 , CCND1 , KPNA2 , MCM4, MKI67 , and STMN1 ) increased after C-ion irradiation under μ G . The cell may pass through the G 1 /S and G 2 checkpoints with DNA damage due to the combined effects of C-ions and μ G , suggesting that increased genomic instability might occur in space.

Space radiation and microgravity (μ G ) are two major environmental stressors for humans in space travel. One of the fundamental questions in space biology research is whether the combined effects of μ G and exposure to cosmic radiation are interactive. While studies addressing this question have been carried out for half a century in space or using simulated μ G on the ground, the reported results are ambiguous. For the assessment and management of human health risks in future Moon and Mars missions, it is necessary to obtain more basic data on the molecular and cellular responses to the combined effects of radiation and µ G. Recently we incorporated a μ G ⁻irradiation system consisting of a 3D clinostat synchronized to a carbon-ion or X-ray irradiation system. Our new experimental setup allows us to avoid stopping clinostat rotation during irradiation, which was required in all other previous experiments. Using this system, human fibroblasts were exposed to X-rays or carbon ions under the simulated μ G condition, and chromosomes were collected with the premature chromosome condensation method in the first mitosis. Chromosome aberrations (CA) were quantified by the 3-color fluorescent in situ hybridization (FISH) method. Cells exposed to irradiation under the simulated μ G condition showed a higher frequency of both simple and complex types of CA compared to cells irradiated under the static condition by either X-rays or carbon ions.

Facilities for heavy ion therapies are steadily increasing in number worldwide. One of the advantages of heavy ions is their high relative biological effect (RBE). In a model used at NIRS (National Institute of Radiological Sciences), linear energy transfer (LET) spectra are required to estimate biological dose (physical dose  ×  RBE). The CR-39 plastic charged-particle detector (CR-39) is suitable for measurement of LET. For the present study, done at the Gunma University Heavy Ion Medical Center (GHMC), we measured LET spectra at 11 depths in spread-out Bragg peak (SOBP) irradiation by a 12 C beam of 380 MeV/u. The lower threshold of the CR-39 to measure LET was about 5 keV µm -1 due to poor sensitivity for low LET. Then we calculated biological dose and survival fraction distributions and compared them with treatment planning results at GHMC. We used Monte Carlo simulation (Geant4) to calculate LET spectra. The simulation results were in good agreement with the experimental spectra. Moreover, the biological dose and survival fraction distributions estimated from the CR-39 reproduced the treatment planning. The CR-39 is suitable for estimating biological dose in carbon ion therapy.

Objective: The common type carcinoma of gastric cancer is divided into 3 groups, papillary adenocarcinoma(pap), well differentiated tubular adenocarcinoma(tub1)and moderately tubular adenocarcinoma(tub2). In this study, we tried to individualize treatments of them by evaluating their clinicopathological features., Methods: Examined resected specimens were collected from 2000 to 2016. We compared among pap, tub1, and tub2 as the clincopathological features retrospectively., Results: Histological diagnosis was confirmed to 55 cases with pap, 639 cases with tub1 and 718 cases with tub2. Comparing the ratio of lymph node metastasis(LNM)according to the depth of invasion, tub2 and pap show higher incidence of LNM than tub1 in T1b, T2, and T4(a+b). Tub2 and pap patients have larger number of LNM and worse 5 year survival rates than tub1 patients., Conclusion: We demonstrated that tub2 and pap may have higher malignancy and show earlier LNM than tub1. When we consider of endoscopic treatment, individualizataing tub1, tub2 and pap is important.

The aim of this research is to develop a stereotactic-radiosurgery (SRS) technique using carbon beams to treat small intracranial lesions; we call this device the carbon knife. A 2D-scanning method is adapted to broaden a pencil beam to an appropriate size for an irradiation field. A Mitsubishi slow extraction using third order resonance through a rf acceleration system stabilized by a feed-forward scanning beam using steering magnets with a 290 MeV/u initial beam energy was used for this purpose. Ridge filters for spread-out Bragg peaks (SOBPs) with widths of 5 mm, 7.5 mm, and 10 mm were designed to include fluence-attenuation effects. The collimator, which defines field shape, was used to reduce the lateral penumbra. The lateral-penumbra width at the SOBP region was less than 2 mm for the carbon knife. The penumbras behaved almost the same when changing the air gap, but on the other hand, increasing the range-shifter thickness mostly broadened the lateral penumbra. The physical-dose rates were approximate 6 Gy s -1 and 4.5 Gy s -1 for the 10  ×  10 mm 2 and 5  ×  5 mm 2 collimators, respectively.

Aim: We aimed to clarify diagnostic and prognostic biomarker potentials of cancer-type organic anion transporting polypeptide 1B3 (Ct-OATP1B3) mRNA in colorectal cancer (CRC) patients., Patients & Methods: Ct-OATP1B3 mRNA levels in 97 CRC and adjacent normal colon tissues were measured by real-time PCR. The receiver operating characteristic curve analysis and the Kaplan-Meier curve analysis were performed to characterize its biomarker potentials., Results: Ct-OATP1B3 mRNA showed noticeable diagnostic power (the area under the receiver operating characteristic = 0.91) in the CRC patients. Additionally, the higher/lower mRNA expression was clearly associated with better/poorer overall survival in the CRC patients (p < 0.05)., Conclusion: Ct-OATP1B3 mRNA has the potential to be a tissue-based biomarker for definitive diagnosis and prognostic stratification in CRC.

Outer space is an environment characterized by microgravity and space radiation, including high-energy charged particles. Astronauts are constantly exposed to both microgravity and radiation during long-term stays in space. However, many aspects of the biological effects of combined microgravity and space radiation remain unclear. We developed a new three-dimensional (3D) clinostat synchronized heavy-ion irradiation system for use in ground-based studies of the combined exposures. Our new system uses a particle accelerator and a respiratory gating system from heavy-ion radiotherapy to irradiate samples being rotated in the 3D clinostat with carbon-ion beams only when the samples are in the horizontal position. A Peltier module and special sample holder were loaded on a static stage (standing condition) and the 3D clinostat (rotation condition) to maintain a suitable temperature under atmospheric conditions. The performance of the new device was investigated with normal human fibroblasts 1BR-hTERT in a disposable closed cell culture chamber. Live imaging revealed that cellular adhesion and growth were almost the same for the standing control sample and rotation sample over 48h. Dose flatness and symmetry were judged according to the relative density of Gafchromic films along the X-axis and Y-axis of the positions of the irradiated sample to confirm irradiation accuracy. Doses calculated using the carbon-ion calibration curve were almost the same for standing and rotation conditions, with the difference being less than 5% at 1Gy carbon-ion irradiation. Our new device can accurately synchronize carbon-ion irradiation and simulated microgravity while maintaining the temperature under atmospheric conditions at ground level., (Copyright © 2017 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.)

A three-dimensional dosimetry method is strongly required in the dose distribution measurement of a patient QA of a heavy ion therapy. Nanocomposite Fricke gel dosimeters are the most possible candidate for this purpose. Experimental dose distribution measurements were carried out using a scanning irradiation port of Gunma University Heavy Ion Medical Center. The result showed no significant LET dependence and indicated a possibility for a precise dosimetry of a heavy ion therapy. It also indicated the importance of three-dimensional dosimetry in the commissioning process of the treatment accelerator.

Purpose: We developed an evaluation method for easily calculating displacement directly between the carbon beam axis and positioning X-ray axis., Methods: A verification image was acquired by irradiating an imaging plate with a carbon beam and X-ray. The X-ray passed through a lead plate inserted in the range compensator holder. The displacement was calculated on the verification image from the center of a wire irradiated with carbon using a multi leaf collimator (MLC) and a wire irradiated with X-ray also using MLC. The accuracy of the method was evaluated by moving the carbon beam axis, the X-ray axis, and the setup angle. The weekly changes of vertical and lateral beams in all rooms were also evaluated., Results: The displacements of the carbon beam axis and the setup angle did not influence the calculation results, whereas the displacement of the X-ray axis did (R=0.999). The displacements including weekly changes were all less than 1.00 mm., Conclusion: An evaluation method for calculating the displacement directly and simply between the carbon beam axis and positioning X-ray axis was developed and verified. The weekly changes of displacement between axes were evaluated to be acceptable at our facility.

We evaluated the difference in effectiveness between preoperative radiotherapy (RT) and chemotherapy (C) as part of multimodal therapy for locally advanced rectal cancer. In the RT group, 43 patients were enrolled and preoperative radiotherapy was performed with 42.6 Gy for 4 weeks. In the C group, 16 patients were treated with preoperative chemotherapy consisting of mFOLFOX6/XELOX plus bevacizumab for 3 months. All 43 tumors in the RT group were located in the lower rectum. The C group was composed of 9 in the lower rectum and 7 in the middle or upper rectum. The C group was more advanced than the RT group in terms of depth of invasion, lymph node metastasis, and tumor diameter. The histological treatment response was better after RT (7 with little, 10 with a minor, 24 with a major, and 2 with a complete response) than after C (10 with little, 4 with a minor, 1 with a major, and 1 with a complete response). The tumor reduction ratio by colonography showed 36.5% after RT and 28.7% after C. CEA was reduced by 47.2% after RT and 45.2% after C. Though RT is more effective for local lesions than C, C is expected to be preferred as the local and systemic therapy for locally advanced rectal cancer with pelvic organ involvement or lateral lymph node metastases.

Gastric carcinoma with lymphoid stroma (GCLS) is a histological type with severe lymphocytic infiltration. GCLS is very rare and few cases have been reported. We examined the clinical features, problems of preoperative diagnosis, and treatment of 14 cases (1.8%) that were diagnosed as GCLS out of 790 gastric cancers surgically resected in our hospital. The mean age was 69 years. Six, 8, and 0 cases were located in the upper, middle, and lower fields of the stomach, respectively, and 8, 1, 4, and 1 cases were macroscopically 0-Ⅱc, 0-Ⅰ, type 2, and type 3, respectively. The depth of invasion was M, SM1, SM2, MP, and SS in 0, 0, 9, 3, and 2 cases, respectively. There were 12 cases(86%)with infection by Epstein-Barr virus, and just 1 case with lymph node metastasis. All cases have had no evidence of recurrence. There were no cases that were diagnosed as GCLS before surgery. GCLS is recognized as having a more favorable prognosis compared with other types of gastric carcinoma, so an aggressive surgery might achieve good outcomes. However, preoperative diagnosis is very difficult and there is a compelling need for new techniques or criteria for diagnosis of GCLS.