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At least 19 recordsLinked to original sources
PubMed1975

Thermography and rheumatic diseases.

The common factor in most of the rheumatic diseases is an arthritis. Radiometry and thermography have been shown to indicate and measure heat resulting from localised inflammation. In rheumatoid arthritis, juvenile arthritis, osteoarthrosis, gout and ankylosing spondylitis abnormal heat distribution has been recorded over affected joints. Experimental evidence has shown that temperature change reflects the inflammatory state of the joint, and that this may be used to measure the effect of therapy by oral, systemic and local drug therapy, and also surgery, i.e. synovectomy.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

The metabolic disposition of norgestrel in female rhesus monkeys.

Following single intragastric doses of d- and dl-[24C]norgestrel (Ng), rhesus monkeys excreted 29.5 +/- 2.0 (SE) and 52.6 +/- 5.4% of the administered radioactivity in urine. Fecal excretion accounted for 57.1 +/- 4.0 and 37.2 +/- 4.4%, respectively. Urinary radioactivity was separated into neutral, acidic, and conjugated fractions. The neutral and conjugated fractions contained Ng; 2 alpha, 16 alpha- and 16 beta-hydroxy-Ng; 3 alpha,5 beta-tetrahydro-Ng and 16 beta-hydroxy-3 alpha,5 beta-tetrahydro-Ng and their glucuronides. However, the bulk of the radioactivity in these fractions was associated with more polar metabolites. The acidic fraction contained unstable metabolies which lose 14CO2 at pH values below 5. The most abundant of these metabolites was isolated as its stable methyl ester. The structure of a 13-ethyl-D-homogon-4-ene-3,17 alpha-dione-17 carboxylic acid is proposed for the metabolite which decomposes to 13-ethyl-D-homogon-4-ene-3,17 alpha-dione [D-homo-G]. The probable mechanism of the metabolite's formation is postulated. Quantitative differences in urinary metabolite patterns were observed following the administration of d- and dl-Ng. Ng is the major identified drug-related entity in plasma. The d-Ng concentrations in plasma measured by radioimmunoassay were in good agreement with those determined by fractionation and radiometry. The latter method indicated the presence of D-homo-G and a glucuronide of 3 alpha,5 beta-tetrahydro-Ng following the administration of d- and dl-Ng.

Animals↗
PubMed1979

Measurements at the piE3 single beam correlated to dosimetry and therapy-planning for the pion applicator at SIN.

Using ionization chambers, aluminium activation, TLD and scintillation counters 3-dimensional total dose-distributions, stardose-distributions and pion stop-distributions have been measured in a single pion beam for various momenta and momentum spreads. It is demonstrated how these data will be used as an input into the therapy-planning program. The techniques developed are suited to check dynamical treatment with 60 pion beams.

Elementary Particles↗
PubMed1977

A sensitive radiometric assay for cysteic acid decarboxylase activity in crude enzyme preparations of rat liver and brain.

1. A method is described for the synthesis of L-[U-14C]cysteic acid from L-[U-14C] cysteine hydrochloride and for its subsequent utilisation as a substrate for cysteic acid decarboxylase activity in liver and brain. 2. The enzyme determination relies on the entrapment of radio-labelled carbon dioxide in Hyamine hydroxide. 3. The assay is sensitive, reliable and convenient and is particularly suitable for measuring the activity of the decarboxylase in crude enzyme preparations.

Animals↗
PubMed1979

Of rads and rem.

Explore the source record for details and available documents.

International System of Units↗
PubMed1975

The new special names of SI units in the field of ionizing radiations.

At its meeting in May-June 1975, the 15th Conference Generale des Poids et Mesures adopted two new special names of SI units; the becquerel, symbol Bq, equal to the second to the power minus one, s-1, for the quantity activity, and the gray, symbol Gy, equal to the joule per kilogram, J-kg-1, for absorbed dose and related quantities in the field of ionizing radiations. This action was preceded by a recommendation of the International Commission on Radiation Units and Measurements (ICRU) in 1974.

International Agencies↗
PubMed1976

[Biomedical use and dosimetry of pions of the sin 590 MeV isochrone cyclotrone. VII. Radiation therapy using negative pions (author's transl)].

The scheme of radiation of Schumacher for high energy electrons is investigated. In it 3 high individual doses are given at first. In the second phase which follows immediately, weekly single doses of 500 rad are given until the tumor is completely destroyed. Reoxygenation and transformation of anoxic cells are important here for the number of surviving tumor cells but unfortunately still rather unknown. This uncertainty can be removed with the Pion therapy in which transformation does not take a large part. About 10 single doses of negative pions of 150-200 rad should be clearly superior to 5000 rad electron doses (D1 = 500 rad) and should not exceed the limits of tolerance with a weekly treatment. Finally the importance of contamination with electrons of the pionrays is examined. Exact measurement of this contamination is necessary.

Bronchial Neoplasms↗
PubMed1979

[Futher means for reducing radiation dose during exposure of the pelvis in infants (author's transl)].

A simple dose-saving procedure for the diagnosis of congenital hip dysplasia employing a diaphragm in nearfocus position is presented. Doses to the skin and the gonads were measured with a phantom for the new and other techniques. With optimal techniques the skin dose is smaller than 2 mR and the gonadal doses lie around 0.1 mR for both male and female patients. An estimate of the dose burden from undesired radiation is appended.

Female↗
PubMed1979

Neutron dosimetry in high energy X-ray beams of medical accelerators.

High energy X-ray beams from medical accelerators are used in cancer therapy. In such beams, neutrons are also produced due to photon-neutron interactions in the target material, collimator and beam flattening filter. The feasibility of employing fast-neutron-induced recoil particle tracks in polycarbonate foils developed by the electrochemical etching (ECE) method for the dosimetry of such neutrons was investigated. The experiments were carried out in, and out of, the beam of a Varian Clinac-18, an Allis-Chalmers 25 MeV betatron and a Brown Boveri 45 MeV betatron. Neutron dose equivalents were found both as a function of the photon dose and of the distance away from the centre of the beam. The neutron dose equivalent was found to be 0.6 and 1.3% of the X-ray dose at the centre position of the beam for a TSD = 100 cm and a 10 x 10 cm2 field for the 25 and 45 MeV betatrons respectively. Although the dosemeter showed adequate sensitivity to neutrons in the beam of the betatrons, it showed insensitivity to neutrons in the beam of the Clinac-18 which has a softer spectrum than the neutron energy threshold of the dosemeter. It can be concluded that this dosimetry method provides a new approach with a number of advantages compared to some other existing techniques for such measurements above the energy threshold of the dosemeter.

Neutrons↗
PubMedDate not supplied

Argon/propane ionization-chamber dosimetry for mixed x-ray/neutron fields.

The photoneutrons produced by high-energy x-ray machines can diffuse through the mazes usually employed at the treatment-room entrance and readily penetrate the lead-lined doors used for x-ray shielding. The measurement of these neutrons in the presence of x-rays and the determination of dose equivalent poses a problem for which there is currently no standard method of solution. In order to separate x-ray dose from neutron dose, the author employed an ionization chamber alternately filled with argon or propane. The response characteristics of this chamber to x-ray and neutrons are described. Quality factors were determined from a calculated neutron spectrum. As a result of these measurements, a 10-in. polyethylene door was added to the entranceway of a 25-MV linear accelerator.

Argon↗