دیکشنری رادیولوژی و هسته ای

بخش هایی از محتوا

Activity فعالیت

The number of nuclear disintegrations occurring per unit of time in a quantity of a radioactive
substance. Activity is measured in Curies or Becquerel. Often used loosely to mean radioactivity.
Alpha: Positively charged particles emitted from the nucleus of an atom. Alpha particles are
relatively large, and very heavy. Due to this strong (+) charge and large mass, an alpha particle
cannot penetrate far into any material. A sheet of paper or an inch of air can usually stop most
alpha particles.

Preface
The Radiological Sciences Dictionary is meant as an easy reference
book for all hospital staff employed in diagnostic imaging, including
established radiologists, nuclear medicine physicians, doctors in
training, physicists, radiographers and technicians. Having understood
the basic meaning and application of any particular keyword,
then wider knowledge should be gained by consulting specialist
books. Keywords in the book are linked so that a particular topic
can be followed by reference to all relevant keywords. This is
designed to aid revision and also act as a guide when exploring a
particular subject. In many instances, keywords are further defined
by showing worked examples. A particular word may be associated
with a given topic (e.g. mammography, digital image filtering, radiation
dose measurement, etc.). Relevant words are then either in
smaller sans serif font when used in the descriptive text or identified
at the end of the word’s description. The author has attempted
to add brief details of clinicians and scientists (alive and dead) who
have, over the years, made significant contributions to diagnostic
imaging. Apologies are given for unintended omissions.
Since new words are regularly being applied to the radiological
sciences, recommendations and suggested additions would be
gratefully received by the publishers. Errors may have made their
appearance and the publishers would also welcome corrections and
constructive comments. All material used will be recognized in
future editions of the dictionary.
DJD
October 2008
Disclaimer: Drugs, contrast media, radiopharmaceuticals and other
compounds for human use, identified in this dictionary, may not be
recognized by individual countries. Relevant national