Page 198 - Pharmaceutics IV (02-06-01305)

c-
c-The radioisotopes for diagnostic use should ideally compounds
with low half-life that eliminate rapid elimination kinetics.

d- The radioisotopes are administered in low doses.

e-Gamma rays are used for diagnosis ,since it is the most
penetrating,,does not stay in the body & quickly received by the
detector.

Technetium 99m ( 99m Tc),a metastable nuclear isomer of
technetium 99 (99 Tc ) ,with a half life of about 6 hrs & biological
elimination

Half life of about one day , the most common isotope used in
medicine .It is more stable & easily transportable parent
isotope,Molybdenum -99 (99 Mo), with a half life of about 66 hrr,in
lead containers.

2-Radiotherapy

The aims to utilize is the tissue damage that results from radiation
to, e.g. reduce the amount of cancerous tissue.

A radiopharmaceutical consists of a drug component & a
radioactive component .Most radionuclides contain component
that emits gamma radiation. Substances that have varying
numbers of protons & neutrons as compared to stable elements
are called Radionuclides

.Nuclides may be stable or unstable ;those that are unstable are
radioactive because their nuclei undergo rearrangement while
changing to stable state & energy is released.

An important distinction between radiopharmaceuticals &
traditional drugs is lack of pharmacological activity on the part of
radiopharmaceuticals .

8