• Nuclear Engineering and Technology
• /
• v.41 no.4
• /
• pp.531-544
• /
• 2009

This paper is intended to provide key issues and current research outcomes on accelerator-based Boron Neutron Capture Therapy (BNCT). Accelerator-based neutron sources are efficient to provide epithermal neutron beams for BNCT; hence, much research, worldwide, has focused on the development of components crucial for its realization: neutron-producing targets and cooling equipment, beam-shaping assemblies, and treatment planning systems. Proton beams of 2.5 MeV incident on lithium target results in high yield of neutrons at relatively low energies. Cooling equipment based on submerged jet impingement and micro-channels provide for viable heat removal options. Insofar as beam-shaping assemblies are concerned, moderators containing fluorine or magnesium have the best performance in terms of neutron accumulation in the epithermal energy range during the slowing-down from the high energies. NCT_Plan and SERA systems, which are popular dose distribution analysis tools for BNCT, contain all the required features (i.e., image reconstruction, dose calculations, etc.). However, detailed studies of these systems remain to be done for accurate dose evaluation. Advanced research centered on accelerator-based BNCT is active in Korea as evidenced by the latest research at Hanyang University. There, a new target system and a beam-shaping assembly have been constructed. The performance of these components has been evaluated through comparisons of experimental measurements with simulations. In addition, a new patient-specific treatment planning system, BTPS, has been developed to calculate the deposited dose and radiation flux in human tissue. It is based on MCNPX, and it facilitates BNCT efficient planning based via a user-friendly Graphical User Interface (GUI).

• Progress in Medical Physics
• /
• v.29 no.4
• /
• pp.123-136
• /
• 2018

The complex dose distribution and dose transfer characteristics of intensity-modulated radiotherapy increase the importance of precise beam data measurement and review in the acceptance inspection and preparation stages. In this study, we propose a process map for the introduction and installation of high-precision radiotherapy devices and present items and guidelines for risk management at the acceptance test procedure (ATP) and commissioning stages. Based on the ATP of the Varian and Elekta linear accelerators, the ATP items were checked step by step and compared with the quality assurance (QA) test items of the AAPM TG-142 described for the medical accelerator QA. Based on the commissioning procedure, dose quality control protocol, and mechanical quality control protocol presented at international conferences, step-by-step check items and commissioning guidelines were derived. The risk management items at each stage were (1) 21 ionization chamber performance test items and 9 electrometer, cable, and connector inspection items related to the dosimetry system; (2) 34 mechanical and dose-checking items during ATP, 22 multileaf collimator (MLC) items, and 36 imaging system items; and (3) 28 items in the measurement preparation stage and 32 items in the measurement stage after commissioning. Because the items presented in these guidelines are limited in terms of special treatment, items and practitioners can be modified to reflect the clinical needs of the institution. During the system installation, it is recommended that at least two clinically qualified medical physicists (CQMP) perform a double check in compliance with the two-person rule. We expect that this result will be useful as a radiation safety management tool that can prevent radiation accidents at each stage during the introduction of radiotherapy and the system installation process.

• Journal of radiological science and technology
• /
• v.33 no.3
• /
• pp.283-288
• /
• 2010

In order to evaluate radiation dose on the uterus and surrounding organs during brachytherapy for cervical cancer, of which the frequency of occurrence is high in Korean women, as well as radiation dose on medical staffs in proximity of patients receiving the therapy, a mathematical phantom based on reference Korean was established and the radiation dose was calculated accordingly. For simulation, $^{192}Ir$, which is useful in brachytherapy, was selected as radionuclide. Also, it was presumed that the intensity of initial radiation was 1 Ci. The result indicated the radiation of 4.92E-14 Gy/Ci in the uterus, the source organ. In addition, radiation on people around patient receiving the therapy was found to be 1.24E-07 Sv at a distance of 30 cm.

• The Journal of the Korea Contents Association
• /
• v.15 no.6
• /
• pp.283-289
• /
• 2015

Recently, high energy photon radiotherapy is a growing trend for increasing therapy results. Commonly, if you use high energy photons above 6~8 MeV nominal accelerator voltage, It lead the photo-nuclear reaction and the generation of photo-neutron are accompanied and these problematic factors are issued in the view of radiation protection. Therefore, in this study analyzed for dose distribution of photo-neutron in radiotherapy room based on MCNPX. As a result, absorbed dose is increased sharply from 10 MV to 12 MV. It was founded that the rapid increasement of photoneutron fluence was related to the absorbed dose at above 10 MV. Also, in case of the recommendation of ICRP 103, the outcome of an exchanged equivalent dose which based on calculated an absorbed dose, showed lower equivalent dose than ICRP 60 by reflecting the contribution of secondary photon for absorbed dose of human body in the low energy band.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.8
• /
• pp.3589-3593
• /
• 2012

Objective: Evaluation and assessment of response rate, duration and toxicity in patients subjected to 5-FU based chemotherapy. Background: The therapeutic ratio shifts with different 5FU/LV regimens and none yet serve as the internationally accepted Gold Standard. A bimonthly regimen of high dose leucovorin is reported to be less toxic and more effective than monthly low dose regimens. We here compare therapeutic responses and survival benefit of the two regimens in poor prognosis patients with advanced colorectal carcinoma. Patients and Methods: A total of 35 patients with histologically confirmed colorectal carcinoma were subjected to de Gramont and Mayo Clinic regimen. Nineteen patients were treated with high dose folinic acid ($200mg/m^2$), glucose 5%, 5-FU ($400mg/m^2$) and 22 hr. CIV ($600mg/m^2$) for two consecutive days every two weeks. These patients had failed responses to previous chemotherapy and were above sixty years of age with poor general status. Sixteen patients (six below 60 years) with progressive disease were subjected to low dose folinic acid ($20mg/m^2$)for five days, 5FU($425mg/m^2$) injection bolus for 5 days, every five weeks. An initial evaluation was made in sixty days and responders were reevaluated at sixty days interval or earlier in case of clinical impairment. Based on positive prognosis, the therapy was continued. Evaluation of treatment response was made on the basis of WHO criteria. Results: The response rate was 44% in thirty four evaluable patients, with 4 complete responses (11.8%) and 11 (32.4%) partial responses. The two schedules were well tolerated, whereas, mild toxicity without WHO Grade ${\geq}2$ events was assessed. The response duration was extended (12 months) in a few patients with age above sixty years treated by high dose bimonthly regimen of 5FU/LV. Conclusion: The regimens are safe and effective in advanced colorectal carcinoma patients with poor general status.

• Clinics in Shoulder and Elbow
• /
• v.12 no.1
• /
• pp.21-26
• /
• 2009

Purpose: The aim of this study was to examine the dose-related effect of extracorporeal shock wave therapy (ESWT) for lateral epicondylitis. Materials and methods: Thirty patients with refractory lateral epicondylitis despite conservative treatment for 6 months were enrolled in this study. The patients were divided randomly into a low- and high-energy group. All patients were treated 3 times with ESWT with an interval of 1 week in a double blinded manner. The mean energy level in the low- and high-energy group was $0.12 mJ/mm^2$ and $0.24 mJ/mm^2$, respectively. The upper extremity functional scales and Mayo elbow scores were measured prospectively at the baseline, 1, 3 and 6 months after ESWT. Results: Significant clinical improvement was observed in both groups after ESWT. The high-energy group showed better pain improvement at 6 months after ESWT (p=0.019). The effect of ESWT was dominant between 1 and 6 months after ESWT than within 1 month. Conclusion: ESWT for lateral epicondylitis demonstrated showed good results regardless of the energy dose. However, a high-energy level was more effective in pain improvement after 6 months of treatment.

• Clinical and Experimental Pediatrics
• /
• v.57 no.9
• /
• pp.379-383
• /
• 2014

Recombinant growth hormone (GH) is an effective treatment for short children who are born small for gestational age (SGA). Short children born SGA who fail to demonstrate catch-up growth by 2-4 years of age are candidates for GH treatment initiated to achieve catch-up growth to a normal height in early childhood, maintain a normal height gain throughout childhood, and achieve an adult height within the normal target range. GH treatment at a dose of $35-70{\mu}g/kg/day$ should be considered for those with very marked growth retardation, as these patients require rapid catch-up growth. Factors associated with response to GH treatment during the initial 2-3 years of therapy include age and height standard deviation scores at the start of therapy, midparental height, and GH dose. Adverse events due to GH treatment are no more common in the SGA population than in other conditions treated with GH. Early surveillance in growth clinics is strongly recommended for children born SGA who have not caught up. Although high dose of up to 0.067 mg/kg/day are relatively safe for short children with growth failure, clinicians need to remain aware of long-term mortality and morbidity after GH treatment.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.19 no.5
• /
• pp.1256-1260
• /
• 2005

The purpose of this study was to investigate the effects of Angelica gigas on jejunal survival, endogenous spleen colony formation and jejunal crypt cells of mice irradiated with Gamma-ray irradiation. The subject of this study includes 42 mice which were divided into each 7 groups. Angelica gigas experiment groups were Angelica gigas + Gamma-ray(10Gy), Angelica gigas + Gamma-ray(3Gy), Angelica gigas. Gamma-ray(1 Gy), Gamma-ray control (10Gy), Gamma-ray control(3Gy), Gamma-ray control(1Gy), Normal groups. In the present study to evaluate the effect of Angelica gigas on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice Gamma-ray with each dose of Gamma-ray irradiation. The results of this study were as follows: In low-dose(1Gy) Gamma-ray radiation were treatment of Angelica gigas showed significantly increased(p<0.05) on the cell death apoptosis in crypt, intestine crypts survival of intestine after gamma-ray irradiation. High-dose(10Gy) Gamma-ray, treatment of Angelica gigas showed significantly increased(p<0.05) on the leukocyte. The above results suggest that Angelica gigas were immunostimulating effectively reduced Gamma-ray irradiation.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.3 no.2
• /
• pp.130-134
• /
• 2005

Lithium is mainly prescribed for manic and depressive disorder, also frequently prescribed for the other diseases such as migraine, cluster headache, alcoholism, and obsessive-compulsive disorder. An acute lithium intoxication occurs in cases of patients ingesting large amount lithium at a time, a chronic lithium intoxication occurs in patients on chronic lithium therapy. Acute or chronic lithium poisoning occurs frequently in case of patients on chronic lithium therapy ingesting larger dose than prescribed. Manifestations of lithium poisoning are various. It is possible nervous, cardiovascular, renal, gastrointestinal and endocrine systems to be involved. Due to intracellular high concentration, mortality rate is high in acute lithium intoxication patients on chronic lithium therapy. We report a case of acutely intoxicated 40-year-old male on chronic lithium therapy. His chief complaints were deterioration and high fever. On his arrival to an emergency department, he was in cardiac arrest. He restored return of spontaneous circultion (ROSC) 5 minutes later after cardiopulmonary cerebral resuscitation (CPCR) and referred to department of internal medicine for hemodialysis. Vigorous treatment was given to the patient, but he was expired at 4th hospital day.

• Progress in Medical Physics
• /
• v.32 no.4
• /
• pp.122-129
• /
• 2021

Purpose: This study aimed to design a multipurpose dose verification phantom for external audits to secure safe and optimal radiation therapy. Methods: In this study, we used International Atomic Energy Agency (IAEA) LiF powder thermoluminescence dosimeter (TLD), which is generally used in the therapeutic radiation dose assurance project. The newly designed multipurpose phantom (MPP) consists of a container filled with water, a TLD holder, and two water-pressing covers. The size of the phantom was designed to be sufficient (30×30×30 cm³). The water container was filled with water and pressed with the cover for normal incidence to be fixed. The surface of the MPP was devised to maintain the same distance from the source at all times, even in the case of oblique incidence regardless of the water level. The MPP was irradiated with 6, 10, and 15 MV photon beams from Varian Linear Accelerator and measured by a 1.25 cm³ ionization chamber to get the correction factors. Monte Carlo (MC) simulation was also used to compare the measurements. Results: The result obtained by MC had a relatively high uncertainty of 1% at the dosimetry point, but it showed a correction factor value of 1.3% at the 5 cm point. The energy dependence was large at 6 MV and small at 15 MV. Various dosimetric parameters for external audits can be performed within an hour. Conclusions: The results allow an objective comparison of the quality assurance (QA) of individual hospitals. Therefore, this can be employed for external audits or QA systems in radiation therapy institutions.