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PubMedDate not supplied

153Sm-EDTMP radionuclide treatment of bony metastatic disease: a radiation protection evaluation.

The aims of the study were the identification and optimization of the radiation protection measures for in-patients who underwent palliative radionuclide therapy for bone metastases with 153Sm-EDTMP activities lower than 3 GBq. The suitability of the preventive procedures from the contamination of places and objects, and for the protection of the hospital staff, other patients and relatives from the danger of external radiation and internal contamination has been evaluated by carrying out a series of measurements both of superficial contamination inside the confinement room and of the dose near the treated patients. The results show that the contamination of the places and the objects close to treated patients is really low. The greatest risk of contamination depended on the management of the physiological waste that, therefore, should be collected and disposed as radioactive one. The measurements of external radiation show that nearby the confinement room the dose limit for public is not exceeded. The same is true for the dose limit of 3 mSv established for relatives who, when taking care treated patients, receive a dose lower than 20 microSv a patient. The fulfillment of the proposed radiation protection measures assures the containment of the risk of exposure and contamination for nursing and medical staff involved in radionuclide-based therapy.

Bone Neoplasms↗
PubMed2001

Radiation shielding of astronauts in interplanetary flights: the CREAM surveyor to Mars and the magnetic lens system for a spaceship.

The radiation absorbed by astronauts during interplanetary flights is mainly due to cosmic rays of solar origin (SCR). In the most powerful solar flares the dose absorbed in few hours can exceed that cumulated in one year of exposition to the galactic component of cosmic rays (GCR). At energies above the minimum one needed to cross the walls of the spaceship there are extrapolations and guesses, but no data, on the angular distribution of SCR's, an information that is necessary for establishing whatever defence strategy. It was therefore proposed of sending to Mars a measurement device, that should continuously collect data during the travel, and possibly also in the orbit around Mars and on the Mars surface. The device should identify the particle and privilege the completeness in the measurement of its parameters. In fact the high energy electrons travel at speed of the light and could be used in the and future dangerous proton component. Also the much less abundant but individually more dangerous ions should be identified. The device should indeed include a magnetic spectrometer and a high granularity range telescope, and a good time of flight measurement. ASI is supporting an assessment study of a possible mission of such a device on board of the 2005 probe to Mars. A parallel technical study is also in progress to define the workable techniques and the possible configurations of a system of magnetic lenses for protecting the crew of a spaceship.

Cosmic Radiation↗
PubMed2001

Radiation measurements on the International Space Station.

The International Space Station (ISS) is becoming a reality with the docking of the Russian Service module (Zarya) with the Unity module (Zaveda). ISS will be in a nominal 51.65-degree inclination by 400 km orbit. This paper reviews the currently planned radiation measurements, which are in many instances, based on experiments previously flown on the Space Shuttle. Results to be expected based on Shuttle measurements are presented.

Cosmic Radiation↗
PubMed1975

Flux of high-LET cosmic-ray particles in manned space flight.

On the Apollo and Skylab missions the high energy heavy ion (HZE) flux was measured by means of plastic nuclear track detectors. Measurements involve the fluxes of high linear energy transfer (LET), 6 < or approximately Z < or approximately 26 particles incident on astronauts and on several biological experiments. Partial results of these measurements are presented; the effects of shielding and solar modulation are discussed.

Collodion↗
PubMed1967

Radiation measurements aboard the fourth Gemini flight.

Two special tissue-equivalent ionization chambers and 5 highly sensitive passive dosimetry packages were flown aboard the recent Gemini 4 flight for the purpose of obtaining precise values of instantaneous dose rate, accumulated dose. and shielding effectiveness. This experiment marked the first time that well-defined tissue dose and radiation survey measurements have been carried out in manned spaceflight operations. Since all measurements were accomplished under normal spacecraft environmental conditions, the biological dose resulted primarily from trapped inner Van Allen Belt radiation encountered by the spacecraft in the South Atlantic Anomaly. The experiment determined the particle type, ionizing and penetrating power, and variation with time and position within the Gemini spacecraft. Measured dose rates ranged from 100 mrad/hr for passes penetrating deeply into the South Atlantic Anomaly to less than 0.1 mrad/hr from lower latitude cosmic radiation. The accumulated tissue dose measured by the active ionization chambers, shielded by 0.4 gm/cm2 for the 4-day mission, was 82 mrad. Since the 5 passive dosimetry packages were each located in different positions within the spacecraft, the total mission surface dose measured by these detectors varied from 73 to 27 mrad, depending upon location and shielding. The particles within the spacecraft were recorded in nuclear emulsion, which established that over 90% of the tissue dose was attributable to penetrating protons. This experiment indicates that the radiation environment under shielded conditions at Gemini altitudes was not hazardous.

Atlantic Ocean↗
PubMed1965

Experimental measurements of the radiation hazards associated with manned space flights.

Tissue-equivalent ionization chambers of special design have been flown on U.S. satellites to determine dose-rate levels in space. A chamber shielded by 4.7 g/cm2 measured doses from energetic protons in the inner Van Allen belt and bremsstrahlung radiation produced by relativistic electrons from the artificial radiation belt formed in July 1962. In November 1962, the maximum dose-rate in space for this shield was 30 rad/hr. Behind 0.4 g/cm2 shielding, the dose-rate peak was 20000 rad/hr. These doses have been determined to be due to artificial electrons in most regions of space, masking the dose arising from energetic protons.

Cosmic Radiation↗
PubMed1975

[Possibilities of dose distribution in the afterloading technic].

Remote (controlled) afterloading installations, offer the possibility to improve the dose distributions of the different applicators, since this apparatus permits the employment of artificial radionuclides with a high specific activity and with low energy of gamma rays. It is therefore possible to incorporate effective shielding into the applicators. The possible individual fitting of the dose distribution, however, demands considerable clinical effort, as the extension of the tumor in question has to be ascertained with sufficient accuracy. Otherwise, underdosage to tumor cells may happen within the shielded area. Most afterloading techniques are using stiff applicators and geometrical fixation within patients; configuration and position of the radiation sources in the patient therefore remain unchanged during the whole irradiation. Thus, it becomes possible to adapt additional external irradiation more exactly than before to the intracavitary dose distribution.

Female↗
PubMed2002

[Radiation exposure in radiological clinics. General remarks].

Radiation exposure has not been a source of major concern since the early days of radiology. However, with recent developments in interventional radiology (IVR), radiation injuries to the patient's skin and lens injuries in interventionists have begun attracting attention. I was elected to the International Commission on Radiological Protection (ICRP) and have been involved together with other members in the preparation of a draft entitled "Avoidance of Radiation Injuries from Medical Interventional Procedures." This document, published in the summer of 2001 as Publication 85, can be summarized in the following three major points: 1) The risk of radiation injury should be explained to the patient prior to IVR (informed consent). 2) Protocols should be prepared to define the number of images to be taken and the fluoroscopy time for each procedure of IVR so that standard radiation doses can be calculated. The radiation dose for each patient can be estimated by referring to these standard doses. 3) If the estimated radiation dose to the patient's skin exceeds 3 Gy (1 Gy for procedures likely to be repeated), the site and dose of radiation given should be recorded in the patient's record. If the dose is more than 3 Gy, the patient should be followed up 10 to 14 days after the procedure.

Humans↗
PubMedDate not supplied

Radiation safety in fluoroscopy.

Fluoroscopy is an important diagnostic and interventional imaging tool that enables clinicians to view dynamic, real-time images of anatomy and function unmatched by other imaging techniques. However, operators must take into account many factors that impact the amount of radiation delivered, particularly over the course of a lengthy interventional procedure. After completing this review, readers will: Understand basic concepts of radiobiology and fluoroscopy systems. Know the typical doses and dose calculations for patients and fluoroscopic personnel. Recognize the pathology of biological effects and common radiation-induced skin injuries. Understand fluoroscopic technique factors to reduce patient exposure. Know the basic methods for controlling occupational exposure for fluoroscopic personnel.

Dose-Response Relationship, Radiation↗
PubMed1968

Correlation of dose rate and spectral measurements in the Inner Van Allen Belt.

Dose rate measurements and the charged particle environment of the Inner Van Allen Belt have been correlated using recent data obtained from the radiation research satellite, OV3-4. Six tissue equivalent ionization chambers, constructed of a material which simulates the muscle tissue response to ionizing radiation, measured the dose rate behind various types and thicknesses of material. The specific shields used for several of the chambers were 0.192 g/cm2 aluminum, 0.797 g/cm2 Lucite and 4.485 g/cm2 brass. The proton and electron spectra were determined with an omnidirectional spectrometer using solid state detectors. The spectral measurements discussed here include geomagnetically trapped protons with energies in the range of 15 to 200 MeV. The proton spectra and dose rates are presented as profiles in terms of the McIlwain parameters of L (1.5, 2.0 and 2.5 earth radii) and the magnetic field B (0.050 to 0.250 gauss). The excellent agreement between the measured dose rate and the theoretically predicted dose rate based on the measured spectra provides justification for the radiation transport techniques now being employed to predict the doses to be encountered during future manned space missions. It was found, however, that a more adequate description of the proton fluxes for energies greater than 50 MeV will be necessary to predict dose rate accurately behind shields of 2.5 g/cm2 thickness or greater.

Cosmic Radiation↗
PubMed2000

[An analysis on thickness effect of lithium fluoride detector in proton measurement].

OBJECTIVE: To theoretically analyze the thickness effect of a LiF detector for proton measurement. METHOD: Thickness effect of the detector was calculated by using the definition of the detector dose under ideal and reasonable hypothesis. RESULT: The thickness effect of the detector was not obvious when protons could penetrate the detector: when proton energy was above 12 MeV, the thickness effect was obvious only on condition that the detector thickness approaches proton range, when proton energy was less than 12 MeV, the thickness effect was not obvious. The thickness effect of the detector was obvious, when protons could not penetrate the detector. CONCLUSION: Thin detectors should be used in low energy proton measurements to avoid thickness effect of the detector.

Fluorides↗
PubMedDate not supplied

[The method based on generalized dosimetric function for estimation of cosmonauts' radiation hazard during long-term space missions].

This paper presents a method of assessment of radiation hazard for cosmonauts. The method is based on a new dosimetric function, which enables a complicated nature of space radiation exposure to be reduced to the condition of a standard irradiation on Earth. It can be obtained on the basis of mean-tissue absorbed dose values calculated for each space radiation source, and transmission coefficients. The transmission coefficients define relative biological effectiveness of radiation and assess the influence on the radiobiological effects of the complex spatial and temporal distribution of the absorbed dose in the cosmonaut's body. The combination of cosmic ionizing radiation with other non-radiation nature factors in flight can be accounted.

Astronauts↗