ABSTRACT
Objective To explore the radiation shielding optimization plan for a medical proton cyclotron developing and commissioning building at various commissioning stages. Methods According to the maximum source termsat different commissioning stages, we used the empirical formula to estimate the instantaneous dose rate at the point of interest outside the shield of the building, and optimized the building’s shielding ateach commissioning stage. Results When adding 1.0 m mobile concrete shielding blocks (“blocks” below) each to wall 3 and wall 4 at the cyclotron commissioning stage, 1.0 m blocks to wall 4 and 1.25 m blocks to wall 5 at the beam transport line commissioning stage, and 1.0 m blocks to wall 9 and 0.4 m blocks to the ceiling at the simulated treatment room commissioning stage, the dose rates at the points of interest outside the shield could meet the dose rate limit requirements. Conclusion The application of mobile concrete shielding blocks not only meets the shielding requirements, but also has economical and space-saving advantages, conforming to the principle of shielding optimization. This can be an approach to the optimization of radiation shielding for high-energy particle accelerators or similar scientific projects.
ABSTRACT
A rapid and sensitive method for analyzing trace β-blockers in complex biological samples,which involved magnetic solid-phase extraction(MSPE)coupled with Fourier transform ion cyclotron reso-nance mass spectrometry(FTICR-MS),was developed.Novel nanosilver-functionalized magnetic nano-particles with an interlayer of poly(3,4-dihydroxyphenylalanine)(polyDOPA@Ag-MNPs)were synthesized and used as MSPE adsorbents to extract trace β-blockers from biological samples.After extraction,the analytes loaded on the polyDOPA@Ag-MNPs were desorbed using an organic solvent and analyzed by FTICR-MS.The method was rapid and sensitive,with a total detection procedure of less than 10 min as well as limits of detection and quantification in the ranges of 3.5-6.8 pg/mL and 11.7-22.8 pg/mL,respectively.The accuracy of the method was also desirable,with recoveries ranging from 80.9％to 91.0％following the detection of analytes in human blood samples.All the experimental results demonstrated that the developed MSPE-FTICR-MS method was suitable for the rapid and sensitive analysis of trace β-blockers in complex biological samples.
ABSTRACT
OBJECTIVE@#To compare the performance of the GE cyclotron MINItrace system before and after the upgrade.@*METHODS@#The upgrade of the MINItrace system included replacing the silver target with the Nb syetem and adopting the latest RF control and management system and lastest ion source system.The failrue rate and production efficiency were retrospectively analyzed before and after the upgrade.@*RESULTS@#After the upgrade, the cyclotron failure rate decreased by 86.2%, the average capacity increased by 45%.@*CONCLUSIONS@#After the upgrade of MINItrace cyclotron, the failure rate is sharply reduced, and the production efficiency is grately improved.
Subject(s)
Cyclotrons/standards , Equipment Failure , Retrospective StudiesABSTRACT
This study analyzes the maintenance and common faults of GE MINItrace Qilin medical cyclotron, and studies three kinds of the machine's faults.
Subject(s)
CyclotronsABSTRACT
Oligosaccharide isomers were distinguished by electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry ( ECD-FT-ICR-MS ) in combination with utiliZing alkali, alkaline earth, and transition metals ( Na+, Ca2+, Ba2+, Mg2+, Mn2+ and Co2+) as charge carriers in electrospray.Maltoheptaose, mannohexaose and laminarihexaose were taken as examples to investigate influence of metal ions on the extent of oligosaccharide fragmentation.The same types of fragmentation ions ( 0,2 A and 2,4 A) were obtained for barium- and calcium-adducted maltoheptaose.Mg2+ and Mn2+ had the similar influence ( 0,2 A, 2,4 A and 2,5 A ).Three cross-ring cleavage ions ( 1,4 A, 2,4 A and 2,5 A ) were generated in the spectrum of cobalt-associated maltoheptaose.But in the case of doping Na+into maltoheptaose, only 0,2 A ion was detected.It was found that the signals in the spectra of mannohexaose and laminarihexaose were worse than that in the spectrum of maltoheptaose, probably resulting from different numbers of adducted metal ions.The isomers, mannohexaose and laminarihexaose could be distinguished by ECD-MS in conjunction with the addition of Ca2+, Mg2+ or Co2+.The addition of Ca2+ was the best choice for analysis of oligosaccharides.
ABSTRACT
Content and type of triacylglycerols(TAGs) in edible oils are closely related with our health,it is of significance to develop a fast and high-efficiency method for the determination of TAGs. In this manuscript, a fast and direct method for qualitative analysis of TAGs was established using matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR-MS). 2,5-DHB was employed as matrix and dichloromethanewas used as solvent for dissolving edible oils. With laser power of 15%,laser frequency of 100 Hz and 100 laser shots, repeatability was evaluated using relative standard deviation (RSD) and less than 10% was obtained. Different kinds of edible oils could be directly distinguished from each other using MS and MS/MS results. With confidence level of 95%, principal component analysis(PCA) results show that 34 different kinds of edible oils were clearly classified. Using this method 5% doped canola in olive was identified directly,indicating that MALDI-FTICR-MS has the potential for rapid analyzing and screening edible oils.
ABSTRACT
A method was developed for the quantification of human growth hormone ( hGH ) by protein purification and isotope dilution-high performance liquid chromatography mass spectrometry ( HPLC-IDMS ) . The hGH was purified and fractionated by fast protein liquid chromatography ( FPLC ) , then hGH molecular weight was accurately determined by Fourier transform ion cyclotron resonance mass spectrometer ( FTICR-MS). The purified hGH was hydrolyzed and the separation was performed on an KINETEX C18 column (150 mmí2 mm I. D. , 2. 6 μm) with water ( containing 0. 1% TFA) and acetonitrile isocratic solution as the mobile phase at a flow rate of 0 . 2 mL/min and 40℃. The electrospray source was operated in the positive ion mode, and monitored in the multiple reaction monitoring ( MRM) mode. The measured hGH molecular weight by FTICR-MS was only 0. 31 Da difference from theoretical value. Three amino ( proline, valine and phenylalanine) were clearly separated by isocratic elution within 5 min. Under the optimized conditions, the content of hGH was 186 . 80 μg/g with a RSD of 0 . 5%. The detection results of hGH in international comparison by this method were consistent with the reference value, which validated the feasibility of the established method. The developed method is simple, practical, accurate, reliable and reproducible, and can be used for the hGH quantitation of pure hGH CRM to provide reference for the routine detection of hGH.
ABSTRACT
Sulfur compounds in the diesel were selectively derived into methylsulfonium salts by reacting with iodomethane in the presence of silver tetrafluoroborate, and characterized by positive-ion electrospray ionization (ESI) fourier transform ion cyclotron resonance (FT-ICR MS). The conversion ratios and react selectivities of the methylation for various sulfur compounds were investigated by gas chromatograph coupled with pulse flame photometric detector (GC-PFPD). Result shows that the sulfur compounds in the diesel can react with iodomethane easily at room temperature, the most of sulfur compound derived into methylsulfonium salts;the homologue of benzothiophene get the higher conversion ratio and react selectivity than the homologue of dibenzothiophene (DBT). It is found that primarily sterically hindered alkylated DBT, for example, 4- or 4-, 6- DBT, is recalcitrant to be methylated. Other than benzothiophenes and dibenzothiophenes, one- and two-ring sulfides, as well as other sulfur compounds with a double bond equivalent (DBE) value ranged from 1 to 12 are identified in the diesel.
ABSTRACT
Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.
Subject(s)
Acceleration , Cyclotrons , Gamma Rays , Graphite , Jurisprudence , Korea , Proton Therapy , Protons , RadioisotopesABSTRACT
This review discusses the production of alpha-particle-emitting radionuclides in radioimmunotherapy. Radioimmunotherapy labeled with alpha-particle is expected to be very useful for the treatment of monocellular cancer (e.g. leukemia) and micrometastasis at an early stage, residual tumor remained in tissues after chemotherapy and tumor resection, due to the high linear energy transfer (LET) and the short path length in biological tissue of alpha particle. Despite of the expected effectiveness of alpha-particle in radioimmunotherapy, its clinical research has not been activated by the several reasons, shortage of a suitable a-particle development and a reliable radionuclide production and supply system, appropriate antibody and chelator development. Among them, the establishment of radionuclide development and supply system is a key factor to make an alpha-immunotherapy more popular in clinical trial. Alpha-emitter can be produced by several methods, natural radionuclides, reactor irradiation, cyclotron irradiation, generator system and elution. Due to the sharply increasing demand of 213Bi, which is a most promising radionuclide in radioimmunotherapy and now has been produced with reactor, the cyclotron production system should be developed urgently to meet the demand.
Subject(s)
Alpha Particles , Cyclotrons , Drug Therapy , Linear Energy Transfer , Neoplasm Micrometastasis , Neoplasm, Residual , Radioimmunotherapy , RadioisotopesABSTRACT
PURPOSE: To evaluate biological characteristics of neutron beam generated by MC50 cyclotron located in the Korea Institute of Radiological and Medical Sciences (KIRAMS). MATERIALS AND METHODS: The neutron beams generated with 15 mm Beryllium target hit by 35 MeV proton beam was used and dosimetry data was measured before in-vitro study. We irradiated 0, 1, 2, 3, 4 and 5 Gy of neutron beam to EMT-6 cell line and surviving fraction (SF) was measured. The SF curve was also examined at the same dose when applying lead shielding to avoid gamma ray component. In the X-ray experiment, SF curve was obtained after irradiation of 0, 2, 5, 10, and 15 Gy. RESULTS: The neutron beams have 84% of neutron and 16% of gamma component at the depth of 2 cm with the field size of 26 x 26 cm2, beam current 20 micro A, and dose rate of 9.25 cGy/min. The SF curve from X-ray, when fitted to linear-quadratic (LQ) model, had 0.611 as alpha/beta ratio (alpha=0.0204, beta=0.0334, R2=0.999, respectively). The SF curve from neutron beam had shoulders at low dose area and fitted well to LQ model with the value of R2 exceeding 0.99 in all experiments. The mean value of alpha and beta were -0.315 (range, -0.254 ~ -0.360) and 0.247 (0.220~0.262), respectively. The addition of lead shielding resulted in no straightening of SF curve and shoulders in low dose area still existed. The RBE of neutron beam was in range of 2.07~2.19 with SF=0.1 and 2.21~2.35 with SF=0.01, respectively. CONCLUSION: The neutron beam from MC50 cyclotron has significant amount of gamma component and this may have contributed to form the shoulder of survival curve. The RBE of neutron beam generated by MC50 was about 2.2.
Subject(s)
Beryllium , Cell Line , Cyclotrons , Gamma Rays , Korea , Neutrons , Population Characteristics , Protons , ShoulderABSTRACT
This paper is described on the development of KOTRON-13 and recent status of PET cyclotron by commercial cyclotron companies. KIRAMS has developed medical cyclotron which is KIRAMS-13. Samyoung Unitech produces KOTRON-13 with transfered technology by KIRAMS. As a part of Regional Cyclotron Installation Project, KOTRON-13 cyclotrons and [18F]FDG production modules are being installed at regional cyclotron centers in Korea. The medical concern with radiation technology has been growing for the last several years. Early cancer diagnosis through the cyclotron and PET-CT have been brought to public attention by commercial cyclotron models in the world. The new commercial cyclotron models are introduced compact low energy cyclotrons developed by CTI, GE, Sumitomo in recent. It produces different short-lived radioisotopes, such as [18F], [11C], [13N] and [15O]. For the better reliability acceleration particle is proton only. The characteristics of new model cyclotrons are changed to lower energy corresponding to less 13 MeV. New models have self-shielding and low power consumption. Design criteria for the different types of commercial cyclotrons are described with reference to hospital demands.
Subject(s)
Acceleration , Cyclotrons , Diagnosis , Korea , Protons , RadioisotopesABSTRACT
This paper introduces the basic principle,structure and technique characteristics of MM50 raceway electron cyclotron.Its clinical application to radiotherapy is discussed.
ABSTRACT
As the amount of PET/CT increases,the amount of cyclotron also increases.Hospitals are confronted with some similar problems in cyclotrons purchase.The article is about the stability,after service,yields of nuclide and the particle energy of cyclotron.The stability of cyclotron is the most important factor,and after service is in the next place,while the yields of nuclide are also very important.
ABSTRACT
PURPOSE: For the research of Boron Neutron Capture Therapy (BNCT), fast neutrons generated from the MC-50 cyclotron with maximum energy of 34.4 MeV in Korea Cancer Center Hospital were moderated by 70 cm paraffin and then the dose characteristics were investigated. Using these results, we hope to establish the protocol about dose measurement of epi-thermal neutron, to make a basis of dose characteristic of epi-thermal neutron emitted from nuclear reactor, and to find feasibility about accelerator-based BNCT. METHOD AND MATERIALS: For measuring the absorbed dose and dose distribution of fast neutron beams, we used Unidos 10005 (PTW, Germany) electrometer and IC-17 (Far West, USA), IC-18, EIC-1 ion chambers manufactured by A-150 plastic and used IC-17M ion chamber manufactured by magnesium for gamma dose. There chambers were flushed with tissue equivalent gas and argon gas and then the flow rate was 5 cc per minute. Using Monte Carlo N-Particle (MCNP) code, transport program in mixed field with neutron, photon, electron, two dimensional dose and energy fluence distribution was calculated and there results were compared with measured results. RESULTS: The absorbed dose of fast neutron beams was 6.47x10-3 cGy per 1 MU at the 4 cm depth of the water phantom, which is assumed to be effective depth for BNCT. The magnitude of gamma contamination intermingled with fast neutron beams was 65.2+/-0.9% at the same depth. In the dose distribution according to the depth of water, the neutron dose decreased linearly and the gamma dose decreased exponentially as the depth was deepened. The factor expressed energy level, D20/D10, of the total dose was 0.718. CONCLUSION: Through the direct measurement using the two ion chambers, which is made different wall materials, and computer calculation of isodose distribution using MCNP simulation method, we have found the dose characteristics of low fluence fast neutron beams. If the power supply and the target material, which generate high voltage and current, will be developed and gamma contamination was reduced by lead or bismuth, we think, it may be possible to accelerator-based BNCT.
Subject(s)
Argon , Bismuth , Boron Neutron Capture Therapy , Boron , Cyclotrons , Electric Power Supplies , Fast Neutrons , Hope , Korea , Magnesium , Neutrons , Nuclear Reactors , Paraffin , Plastics , WaterABSTRACT
Objective To develop the dual-beam technology of cyclotron to produce radioactive nuclide, which can increase radiopharmaceuticals output. Methods A new target is installed in cyclotron standby target, and at the same time the tubes and electronic components are fixed to produce radioactive nuclide through dual-beam technology, the product is tested by the dose calibrator. Results The radioactive nuclide can be produced through dual-beam technology and the output is nearly double times about which a single target. Conclusion The productions of cyclotron radioactive isotope are improved by dual-beam technology and meet the clinical needs of PET/CT examination for drugs.
ABSTRACT
Medical cyclotron supplies the positron isotope for PET examinations. The purpose of QA for medical cyclotron is to keep the cyclotron work well, so it can supply enough and high quality positron isotope. It is important to do the maintenance and serving of the cyclotron. Importance should be attached to the training of operators. At the same time, repairing work and the supply of spare parts are also important.
ABSTRACT
For the physical characterization of neutron beam, dosimetric measurements had been performed to obtain physical data of KCCH cyclotron-produced neutrons for clinical use. The results are presented and compared with the data of other institutions from the literatures. The central aixs percent depth dose, build-up curves and open and wedge isodose curve values are intermediate between that of a 4 and 6 MV X-ray. The build-up level of maximum dose was at 1.35 cm and entrance dose was approximately 40%. Flatness of the beam was 9% at Dmax and less than+/-3% at the depth of 80% isodose line. Penumbra begond the 20% line is wider than corresponding photon beam. The output factors ranged 0.894 for 6 x 6 cm field to 1.187 for 30 x 30 cm field. gamma contamination of neutron beam was 4.9% at 2 cm depth in 10 x10 cm field.
Subject(s)
Cyclotrons , NeutronsABSTRACT
For evaluation of biological effect of p+(50.5 MeV) Be neutron beam produced by Korea Cancer Center Hospital(KCCH) cyclotron the RBE had been measured in experimental tumor Walker 256 carcinosarcoma as well as normal tissue, mouse intestine and bone marrow, in single and fractionated irradiation. As pilot study, the RBE had been measured for the mouse jejunal crypt cells in single whole body irradiation of which the result was 2.8. The obtained RBE values of TCD 50 of Walker 256 tumor, bone marrow and intestine in single irraiation were 1.9, 1.9 and 1.5 respectively. In fractionated irradiation, the RBE value of tumor Walker 256 was decreased as increasing of fraction number and increased as increaing of fraction size.