BACKGROUND: After the resurgence of endemic malaria case in 1993, the number of malaria cases is increasing in succeeding years and most of patients were soldiers who served in the northern parts of Kyeonggi-do and Kangwon-do. Because group donations of blood from soldiers are frequent in these area, it is possible that donated blood from these area cause malaria. So we examined blood donation history of malaria patients to know their donation behavior. METHODS: The subject was 1,671 malaria patients who were diagnosed in 1997 and referred to blood transfusion research institute and their past donation history, time and frequency of donation were examined. The database consisted of malaria patients and blood donors who are known to be related with transfusion-transmitted malaria has been retrieved at each red cross blood center for every blood donors. The results were analyzed from January to December, 1998. RESULTS: About 60% (1,017) of 1,691 malaria patients in 1997 had donated their blood before diagnosis. The number of one time donation was 268; two time 289; more than three time was 460. Two hundred thirty six donors were checked by malaria registry file. In 236 donors, 92 cases were diagnosed with malaria, 96 cases were suspected to have malaria, 48 cases were namesakes. Conclusion: Because some malaria patients donate their blood after their diagnosis, it would be necessary to operate 'the computerized retrieving programme'to detect their donation after the diagnosis. Also, an education for malaria patients for their risk of transmitting malaria and strict history taking from donors for malaria will be required.
Academies and Institutes ; Blood Donors* ; Blood Transfusion ; Diagnosis ; Education ; Gangwon-do ; Gyeonggi-do ; Humans ; Malaria* ; Military Personnel ; Red Cross ; Tissue Donors

PURPOSE: We report the results of an external audit on the absorbed dose of radiotherapy beams independently performed by third parties. For this effort, we developed a method to measure the absorbed dose to water in an easy and convenient setup of solid water phantom. MATERIALS AND METHODS: In 2008, 12 radiotherapy centers voluntarily participated in the external auditing program and 47 beams of X-ray and electron were independently calibrated by the third party's American Association of Physicists in Medicine (AAPM) task group (TG)-51 protocol. Even though the AAPM TG-51 protocol recommended the use of water, water as a phantom has a few disadvantages, especially in a busy clinic. Instead, we used solid water phantom due to its reproducibility and convenience in terms of setup and transport. Dose conversion factors between solid water and water were determined for photon and electron beams of various energies by using a scaling method and experimental measurements. RESULTS: Most of the beams (74%) were within +/-2% of the deviation from the third party's protocol. However, two of 20 X-ray beams and three of 27 electron beams were out of the tolerance (+/-3%), including two beams with a >10% deviation. X-ray beams of higher than 6 MV had no conversion factors, while a 6 MV absorbed dose to a solid water phantom was 0.4% less than the dose to water. The electron dose conversion factors between the solid water phantom and water were determined: The higher the electron energy, the less is the conversion factor. The total uncertainty of the TG-51 protocol measurement using a solid water phantom was determined to be +/-1.5%. CONCLUSION: The developed method was successfully applied for the external auditing program, which could be evolved into a credential program of multi-institutional clinical trials. This dosimetry saved time for measuring doses as well as decreased the uncertainty of measurement possibly resulting from the reference setup in water.
Electrons ; Phenylpropionates ; Uncertainty ; Water

Currently, the dose distribution calculation used by commercial treatment planning systems (TPSs) for high-dose rate (HDR) brachytherapy is derived from point and line source approximation method recommended by AAPM Task Group 43 (TG-43). However, the study of Monte Carlo (MC) simulation is required in order to assess the accuracy of dose calculation around three-dimensional Ir-192 source. In this study, geometry factor was calculated using segmented sources integration method by dividing microSelectron HDR Ir-192 source into smaller parts. The Monte Carlo code (MCNPX 2.5.0) was used to calculate the dose rate D(r,theta) at a point (r,theta) away from a HDR Ir-192 source in spherical water phantom with 30 cm diameter. Finally, anisotropy function and radial dose function were calculated from obtained results. The obtained geometry factor was compared with that calculated from line source approximation. Similarly, obtained anisotropy function and radial dose function were compared with those derived from MCPT results by Williamson. The geometry factor calculated from segmented sources integration method and line source approximation was within 0.2% for r> or =0.5 cm and 1.33% for r=0.1 cm, respectively. The relative-root mean square error (R-RMSE) of anisotropy function obtained by this study and Williamson was 2.33% for r=0.25 cm and within 1% for r>0.5 cm, respectively. The R-RMSE of radial dose function was 0.46% at radial distance from 0.1 to 14.0 cm. The geometry factor acquired from segmented sources integration method and line source approximation was in good agreement for r> or =0.1 cm. However, application of segmented sources integration method seems to be valid, since this method using three-dimensional Ir-192 source provides more realistic geometry factor. The anisotropy function and radial dose function estimated from MCNPX in this study and MCPT by Williamson are in good agreement within uncertainty of Monte Carlo codes except at radial distance of r=0.25 cm. It is expected that Monte Carlo code used in this study could be applied to other sources utilized for brachytherapy.
Anisotropy ; Brachytherapy ; Organothiophosphorus Compounds ; Uncertainty ; Water