PubMed HealthSearch

PubMed · 4085507

Evaluation of background correction methods.

Abstract

After intravenous injection of radioiodinated heptadecanoic acid a high background activity disturbs direct determination of myocardial elimination rates. Several correction procedures for background activity are used. After intracoronary administration a much lower background activity is found. To validate the background subtraction procedures we compared in this study the results of the correction procedures with the results after intracoronary injection of the fatty acid, in which no background subtraction was performed. In ten patients myocardial elimination rates after intracoronary and after intravenous injection were determined. A modified bi-exponential curve fitting procedure, assuming a constant background activity, showed the best results compared with the intracoronary study.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M J van Eenige, F C Visser, A van Lingen, E E Van der Wall, G A Heidendal, J P Roos. 1985. Evaluation of background correction methods.. https://doi.org/10.1093/eurheartj%2F6.suppl_b.57

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Gamma-ray activity and dose rate of brick samples from some areas of North West Frontier Province (NWFP), Pakistan.

It is important to measure natural radioactivity due to gamma-rays from building materials and consequently to determine the dose rate from these materials. This helps to implement precautionary measures whenever the dose rate is found to be above the recommended limits. A knowledge of gamma radioactivity is required by the building construction association to adopt preventive measures to mitigate or minimize the harmful effects of ionizing radiation. The aim of this work was to measure the gamma activity due to 226Ra, 232Th and 40K in bricks from the Peshawar, Nowshera and Mardan districts of NWFP of Pakistan. The radiological doses to the occupants from the brick floor of a wooden house were calculated. The average gamma dose equivalent rate was calculated to be 0.14 mSv per year, which is well below the external gamma dose limit of 0.46 mSv per year as given in UNSCEAR [2].

Background Radiation

Low environmental radiation background impairs biological defence of the yeast Saccharomyces cerevisiae to chemical radiomimetic agents.

Background radiation is likely to constitute one of the factors involved in biological evolution since radiations are able to affect biological processes. Therefore, it is possible to hypothesize that organisms are adapted to environmental background radiation and that this adaptation could increase their ability to respond to the harmful effects of ionizing radiations. In fact, adaptive responses to alkylating agents and to low doses of ionizing radiation have been found in many organisms. In order to test for effects of adaptation, cell susceptibility to treatments with high doses of radiomimetic chemical agents has been studied by growing them in a reduced environmental radiation background. The experiment has been performed by culturing yeast cells (Saccharomyces cerevisiae D7) in parallel in a standard background environment and in the underground Gran Sasso National Laboratory, with reduced environmental background radiation. After a conditioning period, yeast cells were exposed to recombinogenic doses of methyl methanesulfonate. The yeast cells grown in the Gran Sasso Laboratory showed a higher frequency of radiomimetic induced recombination as compared to those grown in the standard environment. This suggests that environmental radiation may act as a conditioning agent.

Background Radiation