What is QC in nuclear medicine?
Quality control (QC), which may be defined as an established set of ongoing measurements and analyses designed to ensure that the performance of a procedure or instrument is within a predefined acceptable range, is thus a critical component of routine nuclear medicine practice.
How should the quality of a nuclear medicine practice be measured?
Test to check: (1) Precision and accuracy for standard measurement geometry with a calibrated, sealed gamma radiation source. (2) Linearity of the activity response, with 99m Tc or 113min in solution. (3) Leakage of radiation shielding.
What is a single probe counting system?
Single probe counting systems using only one crystalline detector are primarily used for measuring thyroid uptake of radioactive iodine. The probe used for thyroid counting is actually similar to the standard well counter in concept ( Fig. 2.4 ), although it does not have the central hole in the sodium iodide crystal.
What does a well counter do?
A well counter is a device used for measuring radioactivity in small samples. It usually employs a sodium iodide crystal detector. It was invented in 1951 by Hal Anger, who is also well known for inventing the scintillation camera.
What is intrinsic resolution?
Intrinsic resolution (Rint ) refers to how well the crystal and PMT system localize an interaction in the crystal. Affected by crystal thickness, gamma ray energy, scatter in crystal.
What determines radiochemical purity?
Generally, all three methods can be performed to determine the radiochemical purity of 99mTc-MIBI. However, to obtain good results, the measurement using dose calibrator and gamma counter for extraction methods must use a minimum sample volume 250 µL.
What equipment is used for count rate?
Before the source is used the background count rate is measured using a Geiger Muller tube connected to a counter. The count rate from the source is then measured at regular fixed intervals over a period of time.
What are the units for radioactivity?
A material’s radioactivity is measured in becquerels (Bq, international unit) and curies (Ci, U.S. unit). Because a curie is a large unit, radioactivity results are usually shown in picocuries (pCi). A picocurie is one trillionth of a curie.
What are the three types of radiation observed on the detector?
The three most common types of radiation are alpha particles, beta particles, and gamma rays.
What is the efficiency of GM counter?
The efficiency, i. e. the counting probability per one quantum of the thick-walled γ-ray counter was computed theoretically by making some simplifying assumptions for several energies between 10 mc 2 and 34 mc 2 (Li-p γ-ray) and for different wall thickness.
How do you calculate well counter efficiency?
Count a blank (background) and the standard for one minute to obtain counts per minute (cpm) for both. Determine the net cpm of the standard by subtracting the background cpm from the standard cpm. Calculate the efficiency (E): E = net standard cpm/activity of standard in dpm.
What is the function of gamma counter?
The gamma counter is an instrument used to measure gamma radiation emitted by a radionuclide in samples collected from patients for detecting certain disease conditions. The gamma counter uses crystals, which emit light when photons from the gamma rays interact with them.
What is flood field uniformity?
The intrinsic flood-field uniformity is one of the quality control procedures to evaluate the response of a gamma camera to a spatially uniform flux of an incident gamma radiation over the field of view.
What does low temporal resolution mean?
It means that it takes ‘a long time’ to acquire two consecutive brain volumes. Usually, fMRI acquires one volume every 2 or 3 seconds. This is a disadvantage, since we have no signal of what happened between that time interval.
What is Radionuclidic impurity?
Radionuclidic purity is defined as “the ratio, expressed as a percentage, of the radioactivity of the desired radionuclide to the total radioactivity of the source”.
What is the difference between CPM and DPM?
The difference between counts per minute (CPM) and disintegrations per minute (DPM) lies in efficiency. Whereas DPM merely measures the number of atoms that decay in one minute given a select amount of radioactive material, CPM provides for the exact quantity of those atoms that have actually decayed.
What unit is CPM?
Count rates They are not SI units, but are de facto radiological units of measure in widespread use. Counts per minute (abbreviated to cpm) is a measure of the detection rate of ionization events per minute.
What amount of radiation is safe?
The ICRP recommends that any exposure above the natural background radiation should be kept as low as reasonably achievable, but below the individual dose limits. The individual dose limit for radiation workers averaged over 5 years is 100 mSv, and for members of the general public, is 1 mSv per year.
What is a thyroid uptake and scan?
A thyroid uptake and scan is a diagnostic imaging scan that allows the radiologist to determine the function of the thyroid.
What are the current nuclear medicine instrumentation procedures for routine QC?
CONCLUSION This article has briefly reviewed, as summarized in Table 2, routine QC procedures of current nuclear medicine instrumentation, including the survey meter, dose calibrator, well counter, intraoperative probe, organ (“thyroid”) uptake probe, γ-camera, SPECT and SPECT/CT scanner, and PET and PET/CT scanner.
What is the radioactive iodine uptake test?
The radioactive iodine uptake test (RAIU) is also known as a thyroid uptake. It is a measurement of thyroid function, but does not involve imaging. Nuclear medicine uses small amounts of radioactive material called radiotracers. Doctors use nuclear medicine to diagnose, evaluate, and treat various diseases.
What are organ uptake probes?
Historically, organ uptake probes have been used almost exclusively for measuring thyroid uptake and are thus generally known as thyroid uptake probes.