No abstract available.
Cyclotrons*

This study analyzes the maintenance and common faults of GE MINItrace Qilin medical cyclotron, and studies three kinds of the machine's faults.
Cyclotrons

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.
Cyclotrons ; Neutrons*

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.
Acceleration ; Cyclotrons* ; Diagnosis ; Korea ; Protons ; Radioisotopes

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.
Cyclotrons/standards* ; Equipment Failure ; Retrospective Studies

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.
Beryllium ; Cell Line ; Cyclotrons* ; Gamma Rays ; Korea ; Neutrons* ; Population Characteristics* ; Protons ; Shoulder

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.
Animals ; Bone Marrow ; Carcinosarcoma* ; Cyclotrons ; Fast Neutrons* ; Intestines ; Korea ; Mice ; Neutrons ; Pilot Projects ; Whole-Body Irradiation

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.
Alpha Particles ; Cyclotrons ; Drug Therapy ; Linear Energy Transfer ; Neoplasm Micrometastasis ; Neoplasm, Residual ; Radioimmunotherapy* ; Radioisotopes*

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.
Acceleration ; Cyclotrons ; Gamma Rays ; Graphite ; Jurisprudence ; Korea ; Proton Therapy ; Protons ; Radioisotopes

BACKGROUND AND CURRENT STATUS OF THERANOSTICS: Therapeutic nuclear medicine (NM) in Bangladesh began in the early 1980s with the application of radioactive iodine for treatment of thyroid cancer and primary hyperthyroidism. Since then, NM practice has remarkably developed in the country with the advancement of instrumentation, radiopharmacy, and information technology. The government took the initiative to establish four PET-CTcenters at different NMcenters, including one at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS). A further development is the installation of a cyclotron center (18-MeV cyclotron) at NINMAS by the government's fund. Currently, NM is providing good health services to oncology patients throughout the country. More than 20 NM centers are functioning in different parts of the country, and therapeutic NM has an important place. However, conventional radioactive iodine still remains the major theranostic application.CHALLENGES AND FUTURE PERSPECTIVE: The expansion and development of therapeutic NM for other cancers have been limited due to a number of challenging factors. A brief overview of the history and current status ofNMin Bangladesh is presented here with an examination of factors that pose as obstacles to the introduction and development of new therapeutic technologies. Finally, future perspectives are discussed with ways to mitigate existing problems and challenges.
Bangladesh ; Cyclotrons ; Financial Management ; Health Services ; Humans ; Hyperthyroidism ; Iodine ; Nuclear Medicine ; Theranostic Nanomedicine ; Thyroid Neoplasms