Radiopharmacy Flashcards
what is nuclear medicine?
scans that give poor anatomical detail but do show functionality of the organs
what are radiopharmaceuticals made out of?
a ‘useful molecule’ that allows us to target the desired organ + a radioactive isotope that allows us to be detected on the imaging
what are the two views of imaging from a gamma camera?
planar imaging or view organs from multiple angles
how is radiation detected?
- radiopharmaceuticals are injected into the pt
- collimator is placed on the patient
- the gamma photons emitted straight-up from the pt is detected by the detector
why do we use a collimator on the pt?
gamma photons are emitted multi-directionally from the pt
this is stopped with the collimator, allowing the physician to differentiate between the different organs and see your desired organ
what is a collimator?
a sheet of lead with holes in areas to allow the visualisation of the your desired organ by gamma photons only exiting through these gaps.
what is the measurements used for radiation?
sievert (Sv)
what factors affect Sv?
- Storing
- Shielding (lead thickness0
why is ALARP important?
as it means that the radiation given to a pt is AS LOW AS REASONABLY POSSIBLE
what are effects of long exposure of radiation?
- effects the bone marrow
- skin reddening / burning
- pelvis radiotherapy = diarrhoea
- neck radiotherapy = vocal chord damage
what is the inverse square rule?
he strength of the X-ray beam is inversely proportional to the square of distance from the source (X). Standing back by double the distance from a source of radiation (d to 2d) will quarter the dose to the radiologist or radiographer.
how can limit radiation exposure?
- time
- distance
- shielding
what are idealistic pharmacokinetics of radiopharmaceuticals?
- short physical half life
- short biological half life
- nature of radioactive decay
what’s the difference between physical and biological Half life?
physical half life - the period of time required to reduce the radioactivity level of a source to exactly one half its original value due solely to radioactive decay.
biological half life - The time required for a biological system, such as that of a human, to eliminate, by natural processes, half of the amount of a substance (such as a radioactive material) that has entered it.
what are becquerels?
rate of disintegration
what are the different type of radioactive decay?
alpha, beta, gamma
what are the properties of alpha particles?
He nucleus, charge +2
large and collides with tissue = very damaging in small areas
easily shielded
no diagnostic agents but potential for therapeutic use
what are the properties of beta particles?
can be positive or negative
smaller than alpha particles - interact less with tissues
valuable for therapy but not diagnosis
what are the properties of beta+ particles?
known as positrons - antimatter
interact with beta -‘ve particles immediately after emission from the nucleus
what happens when B +’ve and B -‘ve particles collide?
produce 2 gamma rays
which is important in diagnostic procedures
what are the properties of gamma rays?
less interaction with tissue
energy emitted gamma ray is constant for a given radionuclide
valuable in diagnostic