Links & Glossary

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• Nuclear Med. Glossary A-D
• Nuclear Med. Glossary E-H
• Nuclear Med. Glossary I-O
• Nuclear Med. Glossary P-R
• Nuclear Med. Glossary S-Z

Nuclear Med. Glossary E-H

The Nuclear Medicine Glossary by Richard Zimmerman, IBA Letters E to H

Effective dose:

the equivalent dose corrected by the weighting coefficient relating to the irradiated tissue (0.05 for the thyroid, 1 for the whole body) expressed in sieverts.

Effective half-life:

radioactive half-life corrected by the biological half-life. With this information, the practitioner can estimate how long a radioactive substance that has been ingested by or injected into a patient will take before generating an effect on the organism (or a certain type of cell or tissue).

EMEA:

European Medicines Evaluation Agency, European Health Authority: decentralised agency of the European Union, located in London. Recently renamed as EMA: European Medicines Agency

Equivalent dose or Dose equivalent:

absorbed dose corrected by a weighting coefficient relating to the radiation (1 for X-rays, β-rays, and γ-rays, 20 for α-rays), expressed in sieverts. This is a value used in radiation protection to take account of the difference in biological effect of the various types of radiation.

External radiotherapy:

method of therapy by irradiation using a source external to the patient (former cobalt therapy, but now X-ray therapeutic beams and also neutron therapy or proton therapy). Domain of the radiotherapist.

FDA:

Food and Drug Administration, American Health Authority.

FDG (Fluorodeoxyglucose):

substance labeled with fluorine-18, most frequently used for diagnosis based on positron emission tomography technology. A radiolabeled glucose analog that allows glucose-consuming cells such as tumor cells to be displayed.

Free radical:

an extremely reactive chemical entity which contains a redundant electron and which is at the origin of later chemical transformations.

Galenic:

study of the method of administering a medication.

Gamma(γ):

radiation of a shorter wavelength than X-rays emitted by certain radionuclides and with very high energy; usable for diagnostic imaging.

Generator:

tool for the production of a radioisotope by the decay of a parent radionuclide from which it is regularly separated by a physical means (column filtration, extraction).

GMP:

Good Manufacturing Practice, the present highest industry standards for drug production. GLP stands for Good Laboratory Practice (Research) and GCP for Good Clinical Practice (Clinical Research and Development).

Gray (gy):

unit of absorbed dose corresponding to one joule per kilogram. The former unit of absorbed dose is the rad, with one gray equaling 100 rads.

Half-life:

radioactive half-life, see Radioactive half-life. The term biological half-life is also used, which corresponds to the time at the end of which half the quantity of a substance has disappeared or been eliminated from a cell by a biological process.