The most common radiation detection equipment includes the following:
Radiation
detection equipment
The
most common radiation detection equipment includes the following:
1. Scintillation detector for the detection of
gamma-radiation emitting probes. A scintillation probe can be suitably modified
to detect the localization of isotopes in the organs of interest. For example,
detec-tion of 131I uptake by the thyroid and the uptake of red blood
cells labeled with 51Cr by the spleen require appropriately modified
gamma scintigraphy equipment.
2.
Scintillation counters are typical laboratory equipment used for the detection
and measurement of ionizing radiation. These counters can be used to test
samples of in vitro testing (such as
drug release or dissolution) and in vivo
samples after digestion into a homogeneous liquid (such as biodistribution
studies). The operating principle of a scintillation counter is the excitation
of a scintillating material, typically a transparent crystal, with the
high-energy photons of the incident ionizing radiation. A scintillating
material is a luminescent material that absorbs incoming high-energy radiation
and reemits the absorbed energy in the form of light. The scintillating
material could be, for example, cesium iodide, to detect protons and alpha
particles, sodium iodide containing small amounts of thallium to detect gamma
radiation, zinc sulfide to detect alpha particles, and lithium iodide to detect
neutrons. This instrumentation also contains a sensitive photomultiplier tube
that converts light energy to electri-cal signal and the needed electronics to
quantitatively process and display this signal.
3. Positron emission tomography (PET) is a functional
imaging technique applied in nuclear medicine to measure whole body metabolism.
It detects gamma rays emitted by a positron-emitting radionuclide 18F
flu-orodeoxyglucose that is administered to the patient as a tracer before the
procedure. A computerized tomography (CT) X-ray scan is con-currently performed
on the patient to construct a three-dimensional (3D) image of the patient,
which is then utilized to construct a 3D location of the radioisotope in the
body in what is known as the CT-PET scan. This scan can detect regional
metabolic activity, as indicated by regional glucose uptake. This scan is
commonly used to detect cancer metastases.
A
similar nuclear medicine tomographic (providing 3D information in 2D
cross-sectional slices) imaging technique is the single-photon emission
computed tomography (SPECT or SPET). This technique is often applied in an
organ-specific way, with the administration of a specific radionuclide or its
conjugate with a targeting ligand.
4.
Geiger counter, also known as the Geiger–Muller counter, is a typ-ical name for
a handheld device for measuring ionizing radiation most commonly used by the
laboratory safety personnel. It detects ionizing radiation, including alpha particles,
beta particles, and gamma rays, using the ionization effect produced by the
radiation in a Geiger–Muller tube. The Geiger–Muller tube is filled with an
inert, unionized gas (He, Ne, or Ar) at low pressure and is equipped with an
anode and a cathode under high voltage (400–600 V). However, there is no flow
of current, since the gas in the chamber is unionized. Ionization of the inert
gas with incident radiation leads to the flow of current in direct proportion
to the amount of incident radiation, which is detected and reported.
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