Environmental health centers for asbestos and their health impact surveys and activities

In 2009, Korea banned the import, transport, and use of asbestos, and the Asbestos Injury Relief Act (AIRA) was promulgated in 2011. Two environmental health centers for asbestos (EHCA), including Pusan National University Yangsan Hospital (PNUYH) and SoonChunHyang University Cheonan Hospital (SCHUCH), were adapted to find environmental asbestos-related diseases (ARDs) and to support the purposes of AIRA. EHCA conducted a health impact survey (HIS) on persons who resided or reside near asbestos factories or mines. A total of 13,433 persons have taken screening examinations in PNUYH EHCA, and 623 persons (4.6%) have had secondary examinations. Of the 21,014 persons who had screening examinations in SCHUCH EHCA, 2490 persons (11.8%) had secondary examinations. Some of those who tested positive for ARDs through HISs filed applications for the asbestos victims’ medical pocketbook (AVMP). Approximately 116 and 612 persons received AVMPs as a result of PNUYH and SCHUCH examinees, respectively. EHCAs have conducted HISs, public relations, and education for asbestos victims, ordinary citizens, and physicians. As HISs are based on voluntary participation, they does not monitor high-risk groups. Active surveillance focusing on high-risk groups has been blocked by the personal information protection act. Although important work has been performed in finding environmental asbestos victims and increasing public awareness on asbestos, it is necessary to improve the current system and registration.

Feasibility Study of Vertical Multileaf Collimator for Determination of Irradiation Size / 의학물리

The purpose of this study was to evaluate feasibility of Vertical Multileaf Collimator for determination of irradiation size using Vertical Multileaf Collimator and lead block to determine 4 different irradiation shape in case of Co-60 gamma-ray and 6 MV X-ray. We chose ion chamber, glass dosimeter and EBT chromic film to compare with Vertical Multileaf Collimator results and lead block results. In case of Co-60 gamma-ray and 6 MV X-ray, the central axis point dose normalized at reference field of lead block with ion chamber results for Vertical Multileaf Collimator were estimated higher than lead block about 5.1%, 4.2%. In case of Co-60 gamma-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 2.2%, 7.8%, 7.2%, 4.0% for reference, circle, triangle, cross field, respectively. In case of 6 MV X-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 6.7%, 6.2%, 3.8%, 6.2% for reference, circle, triangle, cross field, respectively. The results of EBT chromic film, Vertical Multileaf Collimator of penumbra size for all irradiation shape was smaller than lead block of those size that 2.0~3.5 mm for Co-60 gamma-ray, 0.5~1.0 mm for 6 MV X-ray. The results from this study, radiation treatment volume that results in shielding block can be minimized. In addition, during radiation treatment for 2, 3-dimensional radiation therapy using a Vertical Multileaf Collimator of this survey can be used to determine variety of irradiation fields.

Absorbed Dose Determination for a Biological Sample Irradiated by Gamma Rays from a Cs-137 Source / 의학물리

In this study the dosimetric evaluation for a biological sample irradiated by gamma rays from Cs-137 irradiator (Gamma Irradiator, Chiyoda Technol Co., Japan) was performed for radiobiological experiment. A spherical water with a diameter of 3 cm was assumed as a biological sample. The absorbed dose were determined by the air kerma based dosimetric calculation system. The theoretical and Monte Carlo calculations (MCNPX) were performed and compared to evaluate measured air kerma and determined absorbed dose respectively. As a result of comparison with theoretical calculation, the measured air kerma was in good agreement within 3.1% at the distance of 100 and 200 cm from the source. In comparison with Monte Carlo results the determined absorbed dose along the central axis was in good agreement within 1.9% and 3.7% at 100 cm and 200 cm respectively. Although the preliminary results were obtained in this study these results were used as a basis of dosimetric evaluation for radiobiological experiment. Extended study will be performed to evaluate the dose in various conditions of biological samples.

Study on the Evaluation of TRS-398 Quality Factors with Central Electrode Corrections for Small Cylindrical Chambers / 의학물리

The quality factors (kQ,Q0) were evaluated by appling the results recently studied for the effect of central electrode in TRS-398 protocol. The PTW-31010 and IBA-CC13 chambers were used in this study. The quality factors were calculated as a function of beam quality for high energy electron and photon beams and compared with data currently used in TRS-398 protocol. In the PTW-31010 chamber using aluminium electrode, appling the new central electrode collections, the quality factors were 0.4% and 0.9% higher than current TRS-398 data for high energy photon and electron beams respectively. In the IBA-CC13 chamber using C-552 electrode, there are no variations in quality factors compared to TRS-398 data currently used.

The Incidence of Cardiac Arrhythmias is Lower in Isoflurane than Enflurane / 대한마취과학회지

BACKGROUND: There is difference between isoflurane and enflurane in the myocardial sensitization to catecholamines, and their actions on the heart. Enflurane reduces cytoplasmic calcium more than isoflurane. The hypothesis could be suggested that these two volatile anesthetics might cause the different incidences and natures of cardiac arrhythmias. METHODS: The anesthesia was induced by the intravenous injection of thiopental(6 mg, kg-1) and pipecuronium(0.1 mg, kg-1). Two groups were randomly allocated to the patients(n=80) in the maintenance: Group I inhaled isoflurane(1~2%), O2(2 L), and N2O(2 L), Group II, enflurane (1.5~2.5%). Continuous electrocardiographic recordings with Holter monitor were made of those undergoing tympanoplasty during anesthesia. The tapes recorded were scanned using analyzer, and we read out ECG complexes on the screen. Results were categorized as induction, maintenance, and emergence, and inferred from unpaired t-test, and X2-test with p<0.05 considered significant. RESULTS: The results were as follows: 1) The total incidence of cardiac arrhythmias was 65.0%. Isoflurane(52.5%) was lower than enflurane(77.5%) in the incidence. 2) During maintenance and emergence, isoflurane was lower than enflurane in the frequency of supraventicular arrhythmias. 3) Ventricular arrhythmias most frequently occurred in induction. 4) The frequency of supraventricular arrhythmias was more than two times that of ventricular ones. The arrhythmias at the AV junction were the most common, and VPC's the second. CONCLUSIONS: Greatest caution should be paid during peri-induction. It could be suggested that compared to enflurane, isoflurane better be administered for those to whom arrhythmias could be harmful.

The Effects of Intraarticular Bupivacaine and Morphine on Postoperative pain After Knee Arthroscopy / 대한마취과학회지

BACKGROUND: An effective control of postoperative pain may contribute to success of day-case surgery. After knee arthroscopy, local anesthetics was injected into the knee joint to reduce postoperative pain, but results were variable and the duration of action may be short. The recent reports have suggested that intraarticular morphine would provide more effective and longer acting analgesia than expected from the same dose given systemically. METHODS: A randomized, controlled study was conducted in patients undergoing elective knee arthroscopy under general anesthesia to assess the analgesic effect of intraarticular bupivacaine and morphine, either alone or in combination. Patients in group I(n=20) received 20 ml of normal saline as a control; patients in group II(n=20) received 20 ml of 0.25% bupivacaine; patients in group III(n=20) received 5 mg of morphine in 20ml of normal saline; patients in IV(n=20) received a combination of 5 mg of morphine and 50 mg of bupivacaine in 20 ml of normal saline. All the drugs were injected intraarticularly. Postoperative pain was assessed using the VAS at 1, 2, 4, 8, 12, and 24h after the intraarticular injection. Whenever patients want supplemental analgesia, 90 mg of diclofenac(dicknol ) was injected intramuscularly and then the need for supplemental analgesia was recorded. RESULTS: Patients in groups III and IV had significantly lower pain scores than those in groups I and II. There was no significant difference in the pain scores or analgesics requirements between groups III and IV. CONCLUSIONS: We conclude that intraarticular morphine(5 mg) significantly reduces postoperative pain following knee arthroscopy and there is no significant advantage of combining bupivacaine with morphine.

Spinal Anesthesia with 0.5% Plain Bupivacaine: Effects of Patient's Posture and the Temperature of Bupivacaine / 대한마취과학회지

BACKGROUND: Many factors determine the distribution of local anesthetics in the subarachnoid space. These major factors are dosage of local anesthetics, baricity of local anesthetics, position of patient, contour of vertebral column. The temperature of local anesthetics alters the baricity of local anesthetics. At 20oC, the density of 0.5% plain bupivacaine is 1.0003 and generally act as isobaric solution in the CSF. As its temperature lowers, its baricity increases. METHODS: Forty patients (A.S.A I and II) scheduled for lower extremity operation under spinal anesthesia were randomized into four groups; group I (37oC 0.5% bupivacaine, sitting position), group II (37oC 0.5% bupivacaine, 15o head-down position), group III (4oC 0.5% bupivacaine, sitting position), group IV (4oC 0.5% bupivacaine, 15o head-down position). The patients were placed in the sitting position (Group I, III) or lateral decubitus (Group II, IV) and dural puncture was performed at the L3-4 interspace using a midline approach (25-gauge Quincke spinal needle). A free flow of clear cerebrospinal fluid was obtained before administration of drug (37oC 0.5% bupivacaine in Group I, II and 4oC 0.5% bupivacaine in Group III, IV). Patients remained in the sitting position or 15o head-down position for 3 minutes after injection. Patients in each group received a solution that had been previously equilibrated in a stove to 37oC and in a refrigerator to 4oC for more than 1 day. Syringes used to administer the bupivacaine solution were also equilibrated to 37oC and 4oC, respectively. We checked sensory block level using pin-prick test at every 5 minutes. RESULTS: There was statistic significance in sensory block level between Group I, IV and Group II, III. The maximum sensory block level and the time to maximum cephalad spread of analgesia was the T4 level and 9.6 minutes in Group I, the T5 level and 13.5 minutes in Group IV compared to the T9 level and 21 minutes in Group II, the T10 level and 18 minutes in Group III. CONCLUSIONS: The temperature of 0.5% plain bupivacaine affects sensory block level and time to block. It is concluded that the temperature of the injected solution plays an important role in the sensory spread of 0.5% plain bupivacaine.