PURPOSE: The purpose of this study was to investigate variability of doses with same exposure parameters and evaluate radiographic density according to the variability of doses. MATERIALS AND METHODS: Twenty-eight MAX-GLS (Shinhung Co, Seoul, Korea), twenty-one D-60-S (DongSeo Med, Seoul, Korea), and eleven REX-601 (Yoshida Dental MFG, Tokyo, Japan) dental x-ray machines were selected for this study. Surface doses were measured under selected combinations of tube voltage, tube current, exposure time, and constant distance 42 cm from the focal spot to the surface of the Multi-O-meter (Unfors Instruments, Billdal, Sweden). Radiographic densities were measured on the films at maximum, minimum and mean surface doses of each brand of x-ray units. RESULTS: With MAX-GLS, the maximum surface doses were thirteen to fourteen times as much as the minimum surface doses. With D-60-S, the maximum surface doses were three to eight times as much as the minimum surface doses. With REX-601, the maximum surface doses were six to ten times as much as the minimum surface doses. The differences in radiographic densities among maximum, mean, and minimum doses were significant (p< 0.01). CONCLUSION: The surface exposure doses of each x-ray machine at the same exposure parameters were different within the same manufacturer's machines.
Radiation Dosage ; Radiography ; Seoul

Introduction on the factors influence dosage that is equivalent in effectiveness between animals. They comprised drug metabolism, minimum concentration have with effect in serum, the effective time, cellular respiration, organic weight rate comparison with body weight, heat production, cytochrom C, volume of kidney and body surface.
Dosage Forms ; Animal Experimentation

Sustained release dosage forms belong to new forms with innovative bioavailability, in which drug was released in tailored design. If physicians haven't a firm grasp on nature, composition of dosage form and give incorrect instruction for use, model of release dosage of drug will be changed, and drug is not only less effective but also harmful. Author introduced technical rules of preparing sustained release drugs, sustained release dosage forms and pathways of administration
Pharmaceutical Preparations ; Dosage Forms

The aims of this study are (1) to determine the scattered radiation dose levels in routine fluoroscopy procedures and (2) to compare them with the equivalent chest x-rays and also (3) to monitor common techniques and radiation safety measures taken by the medical officers. The study covered a sample of 105 fluoroscopic procedures performed by 18 medical officers. Each officer wore a personal pocket dosimeter inside the lead gown during each procedure. A digital dosimeter was placed near the detector of the fluoroscopy unit while a survey meter was positioned at the control panel area to record the dose levels. There were 14 types of examination included in this study. The total number of images captured was found to be the highest in barium swallow examination with 115 images, almost five times higher compared to the common practices. The longest screening time was observed in barium enema examination which is 9.15 seconds. The median of the scattered dose level was the highest in barium meal examination (165.50 μSv) which is equivalent to 8.28 times of average dose impart by chest x-ray examinations. The number of images and the length of screening time depend on the competency levels of the medical officers. They capture as many images as possible to avoid missing any abnormalities, therefore it will always be better if the fluoroscopist is consulted during each case. They should also consistently practice essential protection by minimizing exposure time, maximizing distance from the source tube and utilizing the radiation shielding.
Fluoroscopy ; Radiation Dosage

This paper introduces the failure phenomenon, failure analysis, maintenance process and method of SIEMENS PRIMUS linear accelerator.
Particle Accelerators ; Radiotherapy Dosage

Molecular hydrogen (H) has been shown to have diverse biomedical effects. As a small molecular gas, hydrogen can be diffused to the target without hindrance. A variety of related hydrogen products used in medical research and public health have been developed. There are various methods of administration of H, mainly including inhaling hydrogen gas, drinking hydrogen water, injecting hydrogen-saline, orally taking solid-state H sustained-release agents, and stimulating intestinal microbiomes to produce hydrogen. Pharmacokinetics of H in vivo vary with methods of administration and thus influence its biomedical effects. This review summarizes the types of H donors and their pharmacokinetics in vivo.
Hydrogen ; administration & dosage ; pharmacokinetics

Advanced Hodgkin's disease is usually treated with six or more cycles of combination chemotherapy. Spontaneous regression of the cancer is very rarely reported in patients with Hodgkin's disease. We present an unusual case of a patient with Hodgkin's disease who experienced complete remission with a single cycle of chemotherapy, followed by pneumonia. The case was a 36-year-old man diagnosed with stage IVB mixed cellularity Hodgkin's disease in November 2000. After treatment with one cycle of COPP-ABV (cyclophosphamide, vincristine, procarbazine, prednisone, doxorubicin, bleomycin, and vinblastine) chemotherapy without bleomycin, the patient developed interstitial pneumonia and was cared in the intensive care unit (ICU) for two months. Follow-up chest computerized tomography (CT), performed during the course of ICU care, revealed markedly improved mediastinal lymphomatous lesions. Furthermore, follow-up whole body CT and 18-fluorodeoxyglucose positron emission tomography showed complete disappearance of the lymphomatous lesions. Four years later, the patient is well and without relapse. This report is followed by a short review of the literature on spontaneous regression of Hodgkin's disease. To the best of our knowledge, this is the first case report of spontaneous remission of Hodgkin's disease in Korea.
Adult ; Antineoplastic Combined Chemotherapy Protocols/*administration & dosage ; Bleomycin/*administration & dosage ; Cyclophosphamide/*administration & dosage ; Doxorubicin/*administration & dosage ; Hodgkin Disease/*complications/*drug therapy ; Humans ; Male ; Pneumonia/*complications ; Prednisone/*administration & dosage ; Procarbazine/*administration & dosage ; Remission, Spontaneous ; Vinblastine/*administration & dosage ; Vincristine/*administration & dosage

PURPOSE: To investigate the presence of adaptive response by low dose radiation in murine tumors in relation to radiation induced apoptosis as well as related mechanism. MATERIALS AND METHODS: Syngeneic murine tumors, OCa-I and HCa-I, were given 0.05 Gy pretreatment followed by therapeutic dose of 25 Gy radiation. Induction of apoptosis was analyzed for each treatment group. Regulating molecules of apoptosis, p53, Bcl-2, Bax, Bcl-X, were also analyzed by Western blotting. RESULTS: In 0.05 Gy pretreatment group of OCa-I, 25 Gy-induced apoptosis per 1000 cells was 229, which was estimated at 30% lower level than the expected (p<0.05). In contrast, this reduction in radiation induced apoptosis was not seen in HCa-I. In the expression of apoptosis regulating molecules, p53 increased in both tumors in response to radiation. Bcl-2 and Bax did not show significant change in both tumors however, the expression of Bcl-2 surpassed that of Bax in 0.05 Gy pretreatment group of OCa-I. Bcl-X was not expressed in OCa-I. In HCa-I, Bcl-X showed increased expression even with 0.05 Gy. CONCLUSION: Adaptive response by low dose radiation is shown in one murine tumor, OCa-I, in relation to radiation induced apoptosis. Apoptosis regulating molecules including Bcl-2/Bax and Bcl-X, appear to related. This study shows an evidence that adaptive response is present, but not a generalized phenomenon in vivo.
Apoptosis* ; Blotting, Western ; Radiation Dosage

OBJECTIVETo investigate the impact of metal implants with different materials on radiation dose distribution based on film measurement method.

METHODSTitanium plate, titanium intramedullary pin and stainless steel plate were set into phantom and irradiated separately by 6 MV and 15 MV X ray from linear accelerator. Dose distributions derived from different materials metal implants were measured and analyzed by film dosimeter.

RESULTSFor 6 MV X ray, the maximum interface dose increments of titanium plate, titanium intramedullary pin and stainless steel plate were 12.3%, 15.4% and 20.3%. As the radiation energy was increased from 6 MV to 15MV, the maximum interface dose increment of the titanium plate rose from 12.3% to 15.1%, the maximum interface dose increment of the steel plate rose from 20.3% to 30.8%.

CONCLUSIONSMetal implants with different materials have obvious impact on radiation dose distribution. With the increase of the metal atomic number and energy of radiation, the degree of elevated dose also increases. These results suggest that correction of dose distribution is required for radiotherapy of patients with metal implants.

Flash radiotherapy is a kind of radiotherapy method using ultra-high dose rate radiation. Compared with the traditional dose rate radiotherapy, it has unique radiobiological advantages. In this paper, the principle of flash radiotherapy, the process and results of biological experiments are summarized. At the same time, the advantages and challenges of flash radiotherapy are analyzed, and the future clinical application is prospected.
Radiotherapy/methods* ; Radiotherapy Dosage ; Technology