No abstract available.

In electron therapy, lead cutout or low-melting alloy block is used for shaping the field. Material for shaping electron field affects the output factor as well as the collimation system. The authors measured the output factors of electron beams for shaped fields from Clinac-18 using ionization chamber of Farmer type on polystyrene phantom. They analyzed the incident energy, collimation system and size of shaped field. For shaped field the variation of output factor for the field (A/P) has appearance of a smooth curve for all energy and all applicator collimator combination. The output factors for open field deviate from the curves for shaped fields. An output factor for a given field can be calculated by equivalent field method such as A/P method, if a combination of applicator and collimator is fixed.
Alloys ; Polystyrenes

National vaccine injury compensation serves as a crucial and significant safety net for individuals affected by government-recommended vaccines during a pandemic, contributing to the community’s overall safety. In the Republic of Korea, compensation for adverse events resulting from coronavirus disease 2019 (COVID-19) vaccinations has been provided through the National Vaccine Injury Compensation Program introduced in 1995. However, there have been limitations with these measures during the COVID-19 pandemic owing to strict criteria for substantiating causality between the vaccine and injury, its nontransparent process of determining whether to compensate, and the compensation amount that is not practically calculated. This article reviewed the Vaccine Injury Compensation Programs in 10 major countries to present implications for improving the Korean system. Expanding the scope of national accountability is essential to compensate for the consequences of adhering to national policies during public health crises. Therefore, valuable insight can be obtained from examining the systems in Germany, Japan, and Taiwan, which have implemented more relaxed criteria for determining causality in compensation cases; Thailand’s system, which provides the mandatory payment of preliminary compensation for damage caused by vaccination; systems in Germany, France, and Japan, which offer compensation for vaccine injuries from a practical perspective; and systems in France and the United Kingdom, which have a process allowing the assessment records to be shared with the claimants.Furthermore, a dedicated agency for vaccine injury compensation, as seen in France, the United Kingdom, and Australia, is necessary to enhance the efficiency of the Korean system.

High energy photon beam margin due to a less side scatter and the other things. But there still remains a penumbra where the dose changes rapidly in the region near the edge of a radiation beam, although it is short in width. It is suggested that the width of the penumbra depends on the source size, distance from source to diaphragm, source to skin distance, and depth in tissue. However, it is also supposed that the other factors influence the penumbra width. In this paper, we investigate changes of the physical penumbra widths according to various field sizes and depths, by using the three dimensional dosimetry system. As a result, we found that as field size and depth increase, the physical penumbra width also increases.
Diaphragm ; Skin

PURPOSE: The purpose of this study was to evaluate the utility of two-phase dynamic CT, early and equilibrium pahse, in the preoperative staging of rectal cancers. MATERIALS AND METHODS: We performed incremental dynamic CT after rectal infusion of water in 34 patients with pathologically proved rectal cancers. Two-phase dynamic CT findings were prospectively analyzed and correlated with surgical and histopathologic findings. A total of 150ml of nonionic contrast medium was intravenously administered with a power injector at a flow rate of 5ml/sec for 30 sec, and two-phase images were obtained at 30 sec(early phase) and 2 min (equilibrium phase) after bolus injection. Local tumor staging and regional lymph node were classified by TNM staging. RESULTS: All 34 rectal cancers showed a moderate to marked enhancement in the early phase and a homogeneous and prolonged enhancement of the entire lesion in the equilibrium phase. T-staging of primary tumors were 85.3%(29/34) in early phase and 70.6%(24/34) in equilibrium phase. The accuracy in determining the perirectal fat invasion of rectal cancer was 92%(23/25) in early phase, and 72%(18/25) in equilibrium phase. The sensitivity & specificity of the regional lymph node metastasis were 63.6% and 79.1% in early phase, and 54.5% and 65.2% in equilibrium phase, respectively. CONCLUSION: Early phase dynamic CT was more accurate for the preoperative staging of rectal cancer than that at equilibrium phase.
Humans ; Lymph Nodes ; Neoplasm Metastasis ; Neoplasm Staging ; Prospective Studies ; Rectal Neoplasms* ; Sensitivity and Specificity ; Water

No abstract available.
Drug Therapy*

PURPOSE: Percutaneous needle aspiration biopsy under the imaging guidance in the diagnosis of intrathoracic diseases has become a standard practice. Core tissue obtained by automated gun biopsy(AGB) is believed to be more diagnostic than materials from fine needle aspiration(FNA) by many cytopathologists. The authors evauated the role of automated gun biopsy in localized pulmonary lesions with respect to the its accuracy and complications. MATERIALS AND METHODS: We performed 107 percutaneous biopsies in localized pulmonary lesions under fluoroscopic guidance among 107 patients:AGB using 18G or 20G was done in 81 patients, and both AGB and FNA was done in 26 patients. RESULTS: Biopsy samples sufficient for histologic diagnosis were obtained in 94(87.9%) of 107 patients, AG8 in 73(90.1%) of 81 patients and AGB and FNA in 21(80.8%) of 26 patients. 11 of 13 negative results were due to inadeguate specimen size for the histologic diagnosis or were composed of necrotic areas, and 2 of 13 negative results were obtained through nontarget tissue. 10 patients developed pneumothorax and 4 of them required chest tube insertion. Minimal hemoptysis was found in 3 patients. CONCLUSION: Percutaneous automated gun biopsy under fluoroscopic guidance was easy and simple method of obtaining specimens of good quality and quantity. It may be an useful procedure in the diagnosis of localized pulmonary lesions.
Biopsy* ; Biopsy, Needle ; Chest Tubes ; Diagnosis ; Hemoptysis ; Humans ; Needles ; Pneumothorax

PURPOSE: Percutaneous needle aspiration biopsy under the imaging guidance in the diagnosis of intrathoracic diseases has become a standard practice. Core tissue obtained by automated gun biopsy(AGB) is believed to be more diagnostic than materials from fine needle aspiration(FNA) by many cytopathologists. The authors evauated the role of automated gun biopsy in localized pulmonary lesions with respect to the its accuracy and complications. MATERIALS AND METHODS: We performed 107 percutaneous biopsies in localized pulmonary lesions under fluoroscopic guidance among 107 patients:AGB using 18G or 20G was done in 81 patients, and both AGB and FNA was done in 26 patients. RESULTS: Biopsy samples sufficient for histologic diagnosis were obtained in 94(87.9%) of 107 patients, AG8 in 73(90.1%) of 81 patients and AGB and FNA in 21(80.8%) of 26 patients. 11 of 13 negative results were due to inadeguate specimen size for the histologic diagnosis or were composed of necrotic areas, and 2 of 13 negative results were obtained through nontarget tissue. 10 patients developed pneumothorax and 4 of them required chest tube insertion. Minimal hemoptysis was found in 3 patients. CONCLUSION: Percutaneous automated gun biopsy under fluoroscopic guidance was easy and simple method of obtaining specimens of good quality and quantity. It may be an useful procedure in the diagnosis of localized pulmonary lesions.
Biopsy* ; Biopsy, Needle ; Chest Tubes ; Diagnosis ; Hemoptysis ; Humans ; Needles ; Pneumothorax

For the study the effects of X -ray irradiation on the development of lens and interactions between optic vesicle and lens, 200 rads X -ray irradiated to the preganat rats (Sprague -Dawley strain) on gestation day 9.5. The rats were sacrificed daily from the gestation day 10.5 to 17.5, and investigated the development of lens with light microscope. The results were as follows; 1. The survival rate of X -irradiated rat fetuses was decreased significantly compared with that of the control group. 2. The mean body weight of the X -irradiated rat fetuses was decreased significantly compared with that of the control group. 3. The congenital anomalies of the eye in the rat fetuses after X -irradiation were anophthalmia, congenital aphakia, lens aplasia, lens luxation, and coloboma of the retina. 4. The critical period of lens development of the Sprague -Dawley rats was considered from GD 9. 5 to GD 10.0. 5. In the X -irradiated rat fetuses on gestation day 9.5, optic vesicle did not developed, but lens developed independently , and moved deeply toward the forebrain vesicle. According to above results, it could be concluded that the development of lens from surface ectoderm might be independent from the inductive influence of optic vesicle, and the movement of lens toward the forebrain vesicle could be mediated by chemotactic factors secreted from the brain vesicle. Further studies are needed to reveal the mechanisms of lens development and interaction between lens and brain vesicle.
Animals ; Anophthalmos ; Aphakia ; Body Weight ; Brain ; Chemotactic Factors ; Coloboma ; Critical Period (Psychology) ; Ectoderm ; Fetus ; Pregnancy ; Prosencephalon ; Rats ; Retina ; Survival Rate

OBJECTIVES: Because effective decolonization options are not available, and treatment options are limited, carbapenem-resistant Enterobacterales (CRE) constitute increasingly threatening nosocomial pathogens. To prevent CRE-associated transmission and ensure patient safety, healthcare personnel and everyone in contact with CRE-infected patients must implement stringent infection control practices. This report describes a CRE outbreak, possibly related to a caregiver at a long-term care facility (LTCF), and presents a new surveillance model to improve the infection control of CRE in Seoul, Korea. METHODS: The Seoul Metropolitan Government surveillance system identified an outbreak of CRE in an LTCF in 2022. We obtained data on the demographic characteristics and contact histories of the inpatients, medical staff, and caregivers. To isolate the inpatients and employees exposed to CRE, we used rectal swab samples and environmental sampling during the study period (May-December 2022). RESULTS: We identified 18 cluster cases (1 caregiver and 17 inpatients) and 12 sporadic cases with CRE, and conducted a complete 197-day follow-up of all cases in the LTCF’s isolation wards. CONCLUSIONS This investigation demonstrated that our surveillance model and targeted intervention, based on the cooperation of the municipal government, public health center, and infection control advisory committee, effectively contained the epidemic at the LTCF. Measures to improve the compliance of all employees in LTCFs with infection control guidelines should also be adopted.