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At least 487 records · Page 27Linked to original sources
PubMed2005

A quality assurance program in dental radiographic units in western Greece.

OBJECTIVE: This survey reports on successful efforts to establish a quality assurance (QA) program for 50 intraoral x-ray units in the public and private sectors in the region of Achaia, Greece. It was conducted in 2 phases, in 1996 and in 2003, including on-site inspections, QA tests, and standard questionnaires. The aim of the study was to assess equipment conditions, knowledge, and adoption of radiographic QA guidelines by general dentists and, more importantly, the impact of the recommendations and training provided. STUDY DESIGN: The tested parameters focused on radiation protection, equipment maintenance, film speed used, film processing conditions, and radiologic characteristics such as voltage, radiation leakage, type of collimation, source-to-skin distance, timer accuracy, and entrance dose. RESULTS: The data gathered in 1996 demonstrate minimal compliance with equipment function requirements and radiation safety measures. 1 The comparative evaluation of all the parameters gathered from the 2 surveys, indicated that in 2003 the vast majority of the dentists followed the recommendations given in 1996. Only 2 dentists persisted in neglecting the guidelines.

Filtration↗
PubMed1998

Radiation safety.

Nursing and radiology staff members can have a difficult time coexisting and communicating as they strive to provide quality care for patients. Misconceptions about safe radiologic practice within the practice of perioperative nursing occur because members of these professional fields are unfamiliar with each other's knowledge and practice guidelines. This article provides an overview of radiologic practice and safety.

Film Dosimetry↗
PubMed1995

Radiolabeled monoclonal antibodies.

Monoclonal antibodies (MoAbs) are biologically engineered proteins designed to bind to antigens emanating from tumor cells. Selected radioactive isotopes are fused with MoAbs to allow radioimmunodetection of external imaging of metastatic deposits in patients with colon cancer. For the past 10 years, radiolabeled MoAbs have improved tumor localization techniques and influenced the clinical management of surgical patients. Intraoperatively, surgeons use appropriately shielded, handheld, gamma detection probes to locate radiolabeled MoAbs and corresponding colon cancers (ie, residual, recurrent tumors). Using gamma detection probes intraoperatively, surgeons can localize nonpalpable occult tumors and disease not suspected from external antibody scans or other traditional diagnostic methods. This success confirms the need for complete tumor resections, thorough scanning of entire tumor beds, and ex vivo scanning of surgical specimens to assess for potential nodal metastases.

Animals↗
PubMed1986

Radiation protection programs in nuclear medicine.

The development of radiation protection programs in nuclear medicine has been stimulated by the greater degree of regulation that exists in this form of medical imaging. A program within an institution will depend on the amount and type of work to be undertaken, the resources available, and the commitment of the individuals involved. These factors may be part of a licensing program or exist within a broader framework. General policy may be set forth in a manual or guidelines distributed to all employees. The continuing review and development of policy is the function of the institutional committee on radiation. This review must consider patients and workers with the objective of reducing overall dose while obtaining the maximum amount of clinical information. The responsibility for radiation protection is shared by the institution, the licensee, and the individual employee.

Humans↗
PubMed1990

Radiation exposure during ureteroscopy.

Use of fluoroscopy during ureteroscopy increases the risk of radiation exposure to the urologist and patient. Radiation entrance dosages were measured at skin level in 37 patients, and at the neck, trunk and finger of the urologist, and neck and trunk of the circulating nurse. Radiation exposure time was measured in 79 patients, and was related to the purpose of the procedure and the type of ureteroscope used, whether rigid or flexible. Exposure could be minimized by decreasing the fluoroscopy time. A portable C-arm fluoroscopy unit with electronic imaging and last image hold mode should be used to minimize exposure time. Lead aprons and thyroid shields should be used by the urologist and other personnel in the endoscopy room.

Endoscopy↗
PubMed1984

Radiation exposure to patient and urologist during percutaneous nephrostolithotomy.

Radiation exposure to the patient and urologist was determined during 60 procedures for percutaneous removal of calculi from the upper collecting system. For male patients the average radiation dose at the surface of the testis was 160 mrem (1.6 mSv.). Surface dose to the female patient at the ovary level averaged 580 mrem (5.8 mSv.). Radiation doses to the small field or region of fluoroscopy on the skin surface anterior to the kidney averaged 25 rem (0.25 Sv.). Radiation exposure to the urologist at collar level averaged 10 mrem (0.1 mSv.) per case. Patient gonad doses from percutaneous nephrostolithotomy are similar to those from a 7-view excretory urogram. Patient surface exposures at the nephrostomy are comparable to skin doses from standard angiographic procedures. The exposure to the urologist is similar to that from other interventional fluoroscopic procedures and is within acceptable limits. Appropriate use of radiological technology and shielding can keep radiation exposures during percutaneous nephrostolithotomy within acceptable limits for patients and physicians.

Adult↗
PubMed1999

Radiation exposure limits for Japanese astronauts.

Starting in 2001, Japanese astronauts will live aboard the International Space Station (ISS) for 3 to 6 months a year. For astronauts, space radiation is primarily hazardous. Therefore, the National Space Development Agency of Japan (NASDA) is developing a system for Space Radiation Safety Operations. This report describes our overall image of Space Radiation Safety Operations aboard the ISS, especially our proceedings in drafting the "Space Radiation Exposure Limits for Japanese ISS Astronauts."

Adult↗
PubMedDate not supplied

MArs Neutron Energy Spectrometer (MANES): an instrument for the Mars 2003 Lander.

We describe the instrument design and detector development for MANES which has been selected to fly on the Mars 2003 Lander. Section 1 explains the need for the spectrometer in determining the increased risk of carcinogenesis for astronauts. Section 2 presents the instrument design including an outline drawing, a cross-sectional view and a detailed block diagram. Sections 3 and 4 describe the low and high energy detector components of the spectrometer and present responses to monoenergetic neutron beams. Sections 5 and 6 explain the design approaches to charged particle discrimination and instrument transfer function modeling.

Equipment Design↗
PubMed1981

Malignant melanoma among employees of Lawrence Livermore National Laboratory.

19 cases of malignant melanoma (MM) were observed during 1972-77 among approximately 5100 employees of the Lawrence Livermore National Laboratory, where high energy physics research is conducted. This number was significantly higher (p less than 2 X 10(-6)) than that expected in a comparable age/race/sex/geographical segment of the population of the San Francisco Bay Area. The excess seemed to occur only among laboratory employees and not among the surrounding community, which suggests that an occupational factor is responsible. Preliminary case-comparison findings suggest that MM risk is not associated with length of employment at the laboratory nor with type of monitored radiation exposure. Although the data did not support an association between MM incidence and all scientific job classifications combined, an excess relative risk was observed among chemists. The reasons for the MM excess have not been identified.

Adult↗
PubMed2001

Solid state microdosimetry.

A review of solid state microdosimetry is presented with an emphasis on silicon-based devices. The historical foundations and basics of microdosimetry are briefly provided. Various methods of experimental regional microdosimetry are discussed to facilitate a comparison with the more recent development of silicon microdosimetry. In particular, the performance characteristics of a proportional gas counter and a silicon microdosimeter are compared. Recent improvements in silicon microdosimetry address the issues of requirement specification, non-spherical shape, tissue equivalence, sensitive volume definition (charge collection complexity) and low noise requirements which have previously impeded the implementation of silicon-based microdosimetry. A prototype based on silicon-on-insulator technology is described along with some example results from clinical high LET radiotherapy facilities. A brief summary of the applications of microdosimetry is included.

Equipment Design↗
PubMed2001

Space radiation dosimetry in low-Earth orbit and beyond.

Space radiation dosimetry presents one of the greatest challenges in the discipline of radiation protection. This is a result of both the highly complex nature of the radiation fields encountered in low-Earth orbit (LEO) and interplanetary space and of the constraints imposed by spaceflight on instrument design. This paper reviews the sources and composition of the space radiation environment in LEO as well as beyond the Earth's magnetosphere. A review of much of the dosimetric data that have been gathered over the last four decades of human space flight is presented. The different factors affecting the radiation exposures of astronauts and cosmonauts aboard the International Space Station (ISS) are emphasized. Measurements made aboard the Mir Orbital Station have highlighted the importance of both secondary particle production within the structure of spacecraft and the effect of shielding on both crew dose and dose equivalent. Roughly half the dose on ISS is expected to come from trapped protons and half from galactic cosmic rays (GCRs). The dearth of neutron measurements aboard LEO spacecraft and the difficulty inherent in making such measurements have led to large uncertainties in estimates of the neutron contribution to total dose equivalent. Except for a limited number of measurements made aboard the Apollo lunar missions, no crew dosimetry has been conducted beyond the Earth's magnetosphere. At the present time we are forced to rely on model-based estimates of crew dose and dose equivalent when planning for interplanetary missions, such as a mission to Mars. While space crews in LEO are unlikely to exceed the exposure limits recommended by such groups as the NCRP, dose equivalents of the same order as the recommended limits are likely over the course of a human mission to Mars.

Cosmic Radiation↗
PubMed2001

Response of silicon-based linear energy transfer spectrometers: implication for radiation risk assessment in space flights.

There is considerable interest in developing silicon-based telescopes because of their compactness and low power requirements. Three such telescopes have been flown on board the Space Shuttle to measure the linear energy transfer spectra of trapped, galactic cosmic ray, and solar energetic particles. Dosimeters based on single silicon detectors have also been flown on the Mir orbital station. A comparison of the absorbed dose and radiation quality factors calculated from these telescopes with that estimated from measurements made with a tissue equivalent proportional counter show differences which need to be fully understood if these telescopes are to be used for astronaut radiation risk assessments. Instrument performance is complicated by a variety of factors. A Monte Carlo-based technique was developed to model the behavior of both single element detectors in a proton beam, and the performance of a two-element, wide-angle telescope, in the trapped belt proton field inside the Space Shuttle. The technique is based on: (1) radiation transport intranuclear-evaporation model that takes into account the charge and angular distribution of target fragments, (2) Landau-Vavilov distribution of energy deposition allowing for electron escape, (3) true detector geometry of the telescope, (4) coincidence and discriminator settings, (5) spacecraft shielding geometry, and (6) the external space radiation environment, including albedo protons. The value of such detailed modeling and its implications in astronaut risk assessment is addressed.

Astronomy↗