Pilot study on interfractional and intrafractional movements using surface infrared markers and EPID for patients with rectal cancer treated in the prone position

OBJECTIVE

To evaluate interfractional and intrafractional movement of patients with rectal cancer during radiotherapy with electronic portal imaging device (EPID) and surface infrared (IR) markers.

METHODS

20 patients undergoing radiotherapy for rectal cancer with body mass index ranging from 18.5 to 30 were enrolled. Patients were placed in the prone position on a couch with a leg pillow. Three IR markers were put on the surface of each patient and traced by two stereo cameras during radiotherapy on a twice-weekly basis. Interfractional isocentre movement was obtained with EPID images on a weekly basis. Movement of the IR markers was analysed in correlation with the isocentre movement obtained from the EPID images.

RESULTS

The maximum right-to-left (R-L) movement of the laterally located markers in the horizontal isocentre plane was correlated with isocentre translocation with statistical significance (p = 0.018 and 0.015, respectively). Movement of the surface markers was cyclical. For centrally located markers, the 95% confidence intervals for the average amplitude in the R-L, cranial-to-caudal (C-C) and anterior-to-posterior (A-P) directions were 0.86, 2.25 and 3.48 mm, respectively. In 10 patients, intrafractional movement exceeding 5 mm in at least one direction was observed. Time-dependent systematic movement of surface markers during treatment, which consisted of continuous movement towards the cranial direction and a sail back motion in the A-P direction, was also observed.

CONCLUSION

Intrafractional movement of surface markers has both cyclic components and time-dependent systematic components. Marker deviations exceeding 5 mm were mainly seen in the A-P direction. Pre- or post-treatment EPID images may not provide adequate information regarding intrafractional movement because of systematic movement in the A-P direction during radiotherapy.

ADVANCES IN KNOWLEDGE

This work uncovered a sail back motion of patients in the A-P direction during radiotherapy. Pre- or post-treatment EPID images may not provide accurate positioning of patients in the A-P direction because of this time-dependent intrafractional motion.

Crosstalk analysis in homogeneous multi-core two-mode fiber under bent condition

We analyze the inter-core crosstalk in homogeneous multi-core two-mode fibers (MC-TMFs) under bent condition by using the coupled-mode equations. In particular, we investigate the effects of the intra-core mode coupling on the inter-core crosstalk for two different types of MC-TMFs at various bending radii. The results show that the inter-core homo-mode crosstalk of LP(11) mode is dominant under the gentle fiber bending condition due to its large effective area. However, as the fiber bending becomes tight, the intra-core mode coupling is significantly enhanced and consequently makes all the inter-core crosstalk levels comparable to each other regardless of the mode. A similar tendency is observed at a reduced bending radius when the difference in the propagation constants between modes is large and core pitch is small.

Role of second-look ultrasound examinations for MR-detected lesions in patients with breast cancer

PURPOSE

To assess the clinical value of second-look ultrasound (US) examination for the evaluation of additional enhancing lesions detected on magnetic resonance (MR) imaging.

MATERIALS AND METHODS

Between May 2008 and February 2011, 794 consecutive patients with histologically confirmed breast cancer underwent breast MR imaging. We included 101 patients with 132 additional enhancing breast lesions detected on MR imaging who underwent second-look US.  The imaging features and lesion category according to the Breast Imaging and Reporting and Data System (BI-RADS) were assessed with MR and US imaging, respectively.

RESULTS

According to the BI-RADS system, 67 lesions (50.8 %) were classified as category 0, 33 lesions (25.0 %) as category 3, and 32 lesions (24.2 %) as category 4. Of the 67 indeterminate lesions on MR imaging, 34 (50.7 %) were demonstrated on second-look US. 11 of these 34 lesions showed suspicious sonographic features, including 1 lesion that showed malignancy (9.1 %, 1/11). Most of the suspicious lesions on MR imaging (26 of 32 BI-RADS category 4 lesions, 81.3 %) were demonstrated on second-look US, and 17 were malignant (65.4 %, 17/26). Of the 6 BI-RADS category 4 lesions without sonographic correlation, 1 was malignant (16.7 %, 1/6).

CONCLUSION

Second-look US examination was useful for evaluating MR-detected lesions in patients with breast cancer.

UV Light and Gas Sensing Properties of Hybrid Sensor Based on Indium-Tin-Oxide Nanocrystals

We proposed a hybrid sensor which is able to detect both UV light and gas species. The sensor was fabricated by screen printing using indium-tin-oxide (ITO) nanocrystals. To improve the UV sensitivity, high temperature annealing (600 degrees C) under an external pressure (0.2 MPa) was applied. We could observe room temperature operation of the sensor under the simultaneous stimulation of UV light and CH4 gas. This is indicating that an improved fire warning is possible by using the proposed hybrid sensor.

Optical performance monitoring technique using software-based synchronous amplitude histograms

We propose and demonstrate a simple technique to monitor both the optical signal-to-noise ratio (OSNR) and chromatic dispersion (CD) by using the software-based synchronous amplitude histogram (SAH) analysis. We exploit the software-based synchronization technique to construct SAHs from the asynchronously sampled intensities of the signal. The use of SAHs facilitates the accurate extraction of the monitoring parameters at the center of the symbol. Thus, unlike in the case of using the technique based on the asynchronous amplitude histogram (AAH), this technique is not affected by the transient characteristics of the modulated signals. The performance of the proposed monitoring technique is evaluated experimentally by using 10-Gbaud quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) signals over wide ranges of OSNR and CD. We also evaluate the robustness of the proposed technique to the signal's transient characteristics.

Gender flip-flop association between genetic variations of NEDD4L and metabolic syndrome in the Kazakh general population

Genetic variation is thought to contribute to etiology of metabolic syndrome (MS). Neural precursor cell expressed developmentally downregulated 4-like gene (NEDD4L) is a candidate gene for MS. This study investigated the relationship between variations of NEDD4L and MS in the Kazakh, which is an ideal population to study the genetic mechanisms of complex diseases such as MS. We screened the promoter and exons of NEDD4L in 48 Kazakh individuals with MS to identify representative variations. By genotyping the representative variations [271420T>C (rs2288774), 271454A>G (rs2288775), and 296921-296923delTTG] in the Kazakh general population, we conducted a case-control study. In female subjects, the distribution of genotypes and alleles of rs2288775 and 296921-296923delTTG differed significantly between the MS pacients and controls. In male subjects, the genotype distributions of 296921-296923delTTG were significantly different between the MS pacients and controls in the dominant model (P = 0.047). After adjustment for age, smoking, and drinking, multivariate logistic regression analysis showed that rs2288775 was significantly associated with MS [for the A/A genotype, odds ratio (OR) = 3.296, P = 0.011] in female subjects. For 296921-296923delTTG, the I/D+D/D genotype was the high-risk genotype for MS in female subjects (OR = 2.791, P = 0.035) and was a protective factor for MS in male subjects (OR = 0.580, P = 0.045). The 296921-296923delTTG variation of NEDD4L is a gender flip-flop associated with MS in Kazakh individuals. The A allele of rs2288775 may be an independent risk factor for MS in Kazakh women. The results suggest that the genetic variations of NEDD4L might be involved in the pathogenesis of MS.

Achievable capacity improvement by using multi-level modulation format in trench-assisted multi-core fiber system

We evaluate the impacts of using multi-level modulation formats on the transmission capacity of the multi-core fiber (MCF) having trench-assisted index profile and hexagonal layout. For this evaluation, we utilize the spectral efficiency per unit area, defined as the spatial spectral efficiency (SSE). The results show that the SSE improvement achievable by using the higher-level modulation format can be reduced due to its lower tolerance to the inter-core crosstalk. We also evaluate the effects of using large effective area on the transmission capacity of the trench-assisted MCF. The results show that the use of large effective area can decrease this capacity due to the increased inter-core crosstalk and lengthened cable cutoff wavelength, although it can help increase the transmission distance. Thus, it is necessary to optimize the effective area of MCF by considering both the SSE and transmission distance. However, the results indicate that the effect of using different effective areas on the SSE-distance product is not significant, and it is not useful to increase the effective area of the trench-assisted MCF to be larger than ~110 μm(2).

Factors associated with early onset post-traumatic syringomyelia

STUDY DESIGN

Retrospective study.

OBJECTIVES

To identify factors associated with the development of early onset post-traumatic syringomyelia within 5 years of spinal cord injury.

SETTING

Department of Rehabilitation Medicine, Pusan National University School of Medicine, Korea.

METHODS

We retrospectively examined the records of 502 patients with traumatic cervical or thoracic spinal cord injury who underwent follow-up magnetic resonance imaging (MRI) examinations more than once a year for at least 5 years. Patients were assessed in terms of the neurological level of injury, the severity of initial spinal cord injury, the use of surgery and the extent of spinal canal involvement. The latter was evaluated by calculating the shortest antero-posterior diameter of the injured vertebral canal and the spinal reserve capacity as shown on MRI at the time of trauma onset and at the time of diagnosis of syringomyelia.

RESULTS

Syringomyelia developed within 5 years in 37 (7.3%) of the 502 patients. The mean age of these 37 patients was 44.6 years (range, 17-67 years) and the mean interval from spinal cord injury to onset of syringomyelia was 38.8 months (range, 2-54 months). The development of post-traumatic syringomyelia within 5 years was not significantly related to the severity or level of injury, the use of spinal surgery or the extent of spinal canal encroachment (P≥0.05 for each comparison).

CONCLUSION

Early onset syringomyelia occurring within 5 years after spinal cord injury was not associated with neurological injury level, severity of injury, the use of spinal surgery or canal encroachment.

Metastatic sarcomatoid carcinoma to liver and bone marrow in renal transplant recipient: due to exacerbation of quiescent renal cancer? A case report

Sarcomatoid carcinoma is a rare tumor with rapid growth and a poor prognosis. A 60-year-old man underwent kidney transplantation. Three months after transplantation, multiple tumors were found in the liver and bone, and the patient died several days later. Pathological examination of liver and bone marrow biopsies revealed metastatic sarcomatoid carcinoma. Pretransplantation, the patient's workup was positive only for mild thrombocytopenia and a complicated cyst with peripheral rim calcification (Bosniak IIF) in the right kidney. Retrospectively, we found the abdominal computed tomography film, which had been examined at another hospital 6 years previously. The calcified complicated cyst was a 3-cm enhancing solid mass in the right kidney, suggesting renal cell cancer. It is possible that the cancer developed from the calcified complicated cyst. In this case, immunosuppressants may have altered malignant cell proliferation, invasion, and the form of metastasis.

An immunohistochemical study of the pancreatic endocrine cells of the Korean golden frog, Rana plancyi chosenica

The regional distribution and quantitative frequency of pancreatic endocrine cells were demonstrated in the Korean golden frog (Rana plancyi chosenica Okada), which is known as a Korean endemic species, for the first time by immunohistochemical methods using specific mammalian antisera to insulin, glucagon, somatostatin and human pancreatic polypeptide (PP). In the pancreas of the Korean golden frog, all four endocrine cell types were demonstrated. Insulin- and glucagon-positive cells were located in the pancreas as single cells or islet-like clusters, respectively. Somatostatin-containing cells were also dispersed in the pancreas as single cells or clusters but in the case of clusters, they are exclusively situated in the marginal regions of insulin- or glucagon-positive cell clusters. PP-containing cells were also distributed as single cells or clusters. Clusters consisted of PP-positive cells are distributed as a core type and a marginally distributed type. Overall, there were 40.84±3.81% insulin-, 26.02±1.71% glucagon-, 7.63±2.09% somatostatin- and 25.51±3.26% PP-IR cells.

Electrochemical isothermal-capacitance-transient spectroscopy: a new depth profiling method of deep levels

The authors report on a new depth profiling method of deep levels, which we call electrochemical isothermal-capacitance-transient spectroscopy (EICTS). This is combined with electrochemical capacitance-voltage using the Schottky barrier of etchable electrolyte and isothermal-capacitance-transient spectroscopy using the capacitance-transient profile at a fixed temperature. We proved its validity by applying to the ZnSe:N epitaxial film of thickness of more than 1000 nm and comparing the characteristics of an obtained deep level with the results measured by conventional deep-level detection techniques. It is expected that EICTS is very effective to assess the deep levels of wide-bandgap semiconductors that suffer from various point defects and their complexes.

Clinical outcomes and prognostic factors in patients with tuberculous destroyed lung

OBJECTIVE

To characterise the prognosis and identify factors contributing to mortality in patients with tuberculous destroyed lung (TDL).

DESIGN

Following a retrospective review of clinical data and radiographic findings, 169 patients with TDL were enrolled in this study. All patients were graded on a 4-point scale (field score 1-4) based on the extent of destroyed lung parenchyma on chest radiography.

RESULTS

The mean patient age was 64 years (range 33-90); 103 (61%) were male. The median number of hospitalisations was 1 (range 0-11) during follow-up, with a mean duration of 31 months (range 0-172). Pneumonia developed in 96 patients (57%), while 50 patients (30%) developed acute respiratory failure requiring mechanical ventilation, 37 (22%) haemoptysis, 24 (14%) spontaneous pneumothorax and 22 (13%) reactivation of tuberculosis. Overall mortality was 28% (47/169), with a median survival of 39 months (range 0-176) after diagnosis. TDL-related mortality was 19% (32/169), and a field score ≥ 3 was the only independent predictor of shorter survival based on a Cox proportional hazards model (HR 3.520, 95%CI 1.51-8.20, P = 0.004).

CONCLUSION

TDL has a poor prognosis, particularly in patients with more extensive lung destruction.

Limitations in fields of vision for simulated young farm tractor operators

Farm tractors account for the majority of deaths and injuries among youths working on North American farms. A vehicle operator's field of vision is an important operational aspect for safe driving. However, very little is known about visual limitations of young tractor operators compared to adult operators. The main purpose of this study was to quantify limitations in fields of vision of children with different anthropometry. The study was based on assessment of 42 farm tractors in popular use in the USA. The results showed that youth operators typically had diminished fields of vision compared to the average adult operator. The degree of visual limitation is greatest for objects at close distances and when objects are straight in front of the operator/tractor. This has serious implications in terms of risks for runovers, rollovers and collisions. Study findings may help illuminate the development of policies and guidelines in tractor-related jobs for children. STATEMENT OF RELEVANCE: This study provides an ergonomic approach for evaluation of children's visual limitations in tractor operations. This approach could be used in other related cases, where children are allowed to operate vehicles.

Sorption of toluene by humic acids derived from lake sediment and mountain soil at different pH

Contamination of soil and groundwater with BTEX compounds (benzene, toluene, ethylbenzene, and xylene) depends on the sorption behavior of these compounds by soil organic matter (SOM) and humic acids (HAs). In this study sorption of toluene by HAs extracted from lake sediment and mountain soil was investigated. HA suspensions were adjusted to pH 4.00, 6.00, or 8.00 and made to the concentration of 200 mg L(-1). Each HA suspension or solution was subjected to particle size analysis using high performance particle sizer (HPPS). The particle size of HA from lake sediment was around 1000-1200 nm while that from mountain soil was 220-320 nm at suspension pH 4.00. Kinetic studies showed that sorption of toluene by the two HAs followed pseudo-first-order and mainly pseudo-zero-order kinetics. At suspension pH 4.00, the sorption of toluene by the two HAs was best described by Langmuir and Temkin adsorption isotherm models. Further, sorption of toluene by the lake sediment HA was significantly greater than that by mountain soil HA. It was thus suggested that the lake sediment HA with larger particle size may develop beneficially chemical conformation for sorption of toluene and related compounds in soil and associated environments.

Diagnostic yield of double-dose gadobutrol in the detection of brain metastasis: intraindividual comparison with double-dose gadopentetate dimeglumine

BACKGROUND AND PURPOSE

Accurate assessment of the number and lesion characteristics of brain metastasis is very important in GKS. The purpose of this study was to compare the diagnostic efficacy of DD gadobutrol in the detection of brain metastases compared with a DD 0.5-mol/L gadolinium contrast, gadopentetate dimeglumine.

MATERIALS AND METHODS

Records of 27 patients (male to female ratio, 15:12; mean age, 57.1 years) diagnosed with brain metastasis and having undergone GKS were retrospectively analyzed. All patients underwent the first 3D-T1-GRE MR imaging with a DD of gadopentetate dimeglumine. The second MR imaging with a DD of gadobutrol was performed during GKS by using the same parameters used for the first scan. Two neuroradiologists counted the number of enhancing lesions on 2 consecutive MR imaging examinations and reached consensus. Lesion-brain CNR was measured from 45 lesions, and paired t test analysis was performed between DD gadopentetate dimeglumine and gadobutrol MR imaging.

RESULTS

On DD gadopentetate dimeglumine-enhanced images, a total of 130 lesions were detected visually. With DD gadobutrol, 25 additional lesions were detected on GKS MR imaging. There was no missing lesion on DD gadobutrol MR imaging. The mean lesion-brain CNR was higher on DD gadobutrol MR imaging than on DD gadopentetate dimeglumine imaging (2.17 +/- 0.19 versus 1.90 +/- 0.26; P = .00011, paired t test, 2-tailed). Only 2 cases showed lower CNR on DD gadobutrol images: 1 with hemorrhagic metastasis from renal cell carcinoma and the other with steroid treatment after the first MR imaging.

CONCLUSIONS

DD 1.0-mol/L gadobutrol provides higher lesion conspicuity and enhances lesion detection in brain metastasis compared with DD 0.5-mol/L gadolinium contrast agents.

Prophylactic gastrostomy tubes for patients receiving radical radiotherapy for head and neck cancers: a retrospective review

Patients undergoing radical radiotherapy for head and neck cancers often experience significant complications. We sought to evaluate the impact of prophylactic gastrostomy tubes (PGTs) among these patients on four easily evaluable adverse outcomes, namely, absolute weight loss, percentage weight loss, admissions for nutritional reasons and treatment interruptions. A retrospective review was carried out on patients undergoing radical radiotherapy for primary head and neck cancers from September 1999 to October 2005 at the Wellington Blood and Cancer Centre (n = 71). PGTs were placed in 7 (10%) patients. Patients with PGTs were compared with the patients without PGTs (the control group) by univariate and multivariate analyses. By univariate analysis, there was no significant difference in absolute or percentage weight loss between those with PGTs and the control group. By multivariate analysis, those with PGTs lost 5.2% (P = 0.016) less weight than the control group. There were no significant differences between the two groups with regard to admissions for nutritional reasons or treatment interruptions. The use of PGTs can reduce weight loss in patients undergoing radical radiotherapy for head and neck cancers, and its use should be further evaluated in future studies.

Long QT syndrome and torsades de pointes induced by acute sulpiride poisoning

Sulpiride, a selective dopamine D2 antagonist and a substituted benzamide derivative, is considered a safe antipsychotic and antidepressant agent with few adverse effects on the cardiovascular system. Sulpiride-induced torsades de pointes is rare. We report a case of long QT syndrome and torsades de pointes induced by ingestion of 1.5 g of sulpiride. Ventricular arrhythmia was initially treated with amiodarone, without success. Eventually, lidocaine and magnesium sulfate successfully terminated the ventricular arrhythmia. The patient was discharged uneventfully after 3 days of hospitalization. This case illustrates the fact that acute sulpiride poisoning may lead to life-threatening ventricular arrhythmia. Early recognition followed by effective therapy is crucial. Intensive cardiac monitoring is recommended for sulpiride poisoning.

Adaptive fuzzy switched swing-up and sliding control for the double-pendulum-and-cart system

In this paper, an adaptive fuzzy switched swing-up and sliding controller (AFSSSC) is proposed for the swing-up and position controls of a double-pendulum-and-cart system. The proposed AFSSSC consists of a fuzzy switching controller (FSC), an adaptive fuzzy swing-up controller (FSUC), and an adaptive hybrid fuzzy sliding controller (HFSC). To simplify the design of the adaptive HFSC, the double-pendulum-and-cart system is reformulated as a double-pendulum and a cart subsystem with matched time-varying uncertainties. In addition, an adaptive mechanism is provided to learn the parameters of the output fuzzy sets for the adaptive HFSC. The FSC is designed to smoothly switch between the adaptive FSUC and the adaptive HFSC. Moreover, the sliding mode and the stability of the fuzzy sliding control systems are guaranteed. Simulation results are included to illustrate the effectiveness of the proposed AFSSSC.

Ability of youth operators to reach farm tractor controls

Farm tractor work is commonly assigned to young people on North American farms, where tractors account for the majority of deaths and major portions of non-fatal trauma to working youths. However, little is known about the potential mismatch between the anthropometric and physical characteristics of children and tractor characteristics. The purpose of this study was to evaluate the ability of children of varying ages and percentiles to reach major controls on 45 tractors in common use in the US. The main study finding was that many tractor controls, especially those that are hand-operated, may not be effectively reached by the majority of youth operators aged 12 to 16 years. The study raises further serious questions about the ability of children to safely operate tractors in common use on US farms and calls for reconsideration of age guidelines for the assignment of children to tractor work on farms. This study provides novel ergonomic evidence about the ability of children to reach controls inside agricultural tractor cabins. The approach could be applied in similar situations where youths may operate other vehicles or machines. Study findings support the establishment and refinement of policies and guidelines related to youth tractor operation.

The sandwich sign of non-lymphomatous origin

PURPOSE

To investigate the etiologies of the sandwich sign other than lymphoma.

METHOD

The images of 34 patients with sonographic sandwich sign over a 5-year period were retrospectively reviewed. The etiology was based on the pathologic report of mesenteric lymph nodes, or the presence of extensive metastatic disease in case of known advanced primary cancer or disappearance of the sign after specific treatments.

RESULTS

Malignancy accounted for the majority of cases (91%), and was divided into non-Hodgkin's lymphoma (50%) and metastatic carcinomas (41%). Mycobacterium tuberculosis infection was diagnosed in a previously healthy patient, and 2 patients with acquired immunodeficiency syndrome had Mycobacterium avium-complex infection. The sandwich sign was 1 of the initial presentations in 11 cases with newly diagnosed malignancies, including 6 cases of non-Hodgkin's lymphoma and 5 cases of metastatic carcinomas.

CONCLUSION

Metastatic carcinomas, M. avium-complex, and M. tuberculosis infection may produce the sandwich sign. Searching for etiologies other than lymphoma is important in patients presenting with the sandwich sign.

Forces required to operate controls on farm tractors: implications for young operators

Farm tractors account for the majority of fatal injuries to adolescents working in agriculture and therefore remain a leading occupational priority. The question of whether these injuries occur because adolescents are assigned tractor jobs beyond their physical capabilities has not been answered. The purpose of this study was to estimate the activation forces required to operate controls on 40 tractors in common use in the US and compare them with existing estimates of physical strength for children of varying ages and with recommended ergonomic force limits for repeatedly engaging controls. Activation forces for steering, brakes and clutch were measured on each tractor. The main study finding was that the activation forces required to operate tractors typically exceeded the physical abilities of most children aged 13 to 17 years. This raises serious questions about the ability of children to safely operate tractors in common use on US farms. This study provides an ergonomic approach for evaluating the potential mismatch between young people's strength capabilities and forces required in operating farm tractors. This approach could be used in similar situations where adolescents may operate vehicles (e.g. all-terrain vehicles), machinery or other mechanical devices requiring activation of levers and controls. Study findings potentially inform the establishment of occupational policies surrounding tractor operation by young people.

Particle separation to enhance the efficiency of soil acid washing--case study on the removal of cadmium from contaminated soil in southwestern Taiwan

The current trend in remediating contaminated soil by acid washing is to separate the soil mass by their particles sizes prior to washing. However, there is little information about the cost-effectiveness of this practice in literature. In this research, a cadmium-contaminated agricultural field has been selected for conducting a comparative study on cadmium removal by applying the acid washing method to soil samples with and without prior particle separation. The study provides valuable information for the advancement of this method to remediate contaminated soil. The results indicate that sand particles constitute about 70% of the total soil mass but only 24% of the total cadmium. After acid washing once, less than 2% of cadmium remains; multiple washing of the sand portion is thus not cost-effective. Furthermore, after particle separation, the soil mass that needs to be washed is greatly reduced to 35%; the total cost is reduced by about one third due to the savings in the acid solution utilization and the treatment of used acid solution.

A review of recent unexpected animal disease events in Japan and Korea and the follow-up action taken

In Japan, the need to improve countermeasures against biological weapons was recognised after the Aum Shinrikyo cult attempted to use biological weapons in 1995. This paper describes how the two relevant ministries in Japan worked together to cope with recent disease outbreaks, including cases of classical swine fever (CSF) and avian influenza, which evidence suggests might have been the result of the deliberate misuse of unauthorised vaccines that had been illegally imported. By implementing successful control measures the two ministries were able to eradicate all the diseases within very short periods. In the past few years, the Republic of Korea has also experienced outbreaks of foot and mouth disease, highly pathogenic avian influenza, and CSF, all of which had previously been absent (or had been eradicated) in Korea. A review of the historical background, major events of the outbreaks and the control measures which were implemented are presented here.