Related Experiment Video
Updated: Aug 10, 2026
07:31
Characterization of Recombination Effects in a Liquid Ionization Chamber Used for the Dosimetry of a Radiosurgical Accelerator
Published on: May 9, 2014
An ionization chamber as a secondary standard for activity
Summary
The Slovak Institute of Metrology calibrates radionuclide activity meters using a commercial calibrator and reference sources. Long-term stability checks reveal an annual efficiency decrease requiring correction for accurate nuclear medicine measurements.
Area of Science:
- Metrology
- Nuclear Medicine
- Radiochemistry
Background:
- A commercial radionuclide calibrator is essential for maintaining activity units at the Slovak Institute of Metrology (SMU).
- This instrument verifies activity meters crucial for nuclear medicine applications.
Purpose of the Study:
- To describe the calibration process of the radionuclide calibrator.
- To assess the long-term stability and establish an energy-dependent efficiency curve for accurate activity measurements.
Main Methods:
- Long-term stability was monitored using Cesium-137 (137Cs) and Radium-226 (226Ra) reference sources.
- An energy-dependent efficiency curve was determined by transferring calibration factors from the Physikalisch-Technische Bundesanstalt (PTB).
- Measurements with various radionuclide activity standards validated the efficiency curve.
Main Results:
- A consistent decrease in efficiency of approximately 2% per year was observed and quantified.
- The established energy-dependent efficiency curve allows for the calculation of calibration factors for short-lived radionuclides.
- Overall uncertainty for activity measurements using calculated factors was determined to be less than 1.8%.
Conclusions:
- The calibration method ensures accurate activity measurements for nuclear medicine applications.
- The observed efficiency drift necessitates regular corrections for reliable long-term performance.
- The developed methodology enables precise calibration for a wide range of radionuclides, enhancing metrological capabilities.
Related Concept Videos
01:16Mass Spectrometers
This lesson details the instrumentation of a mass spectrometer—a physical instrument to perform mass spectrometry on analyte molecules and record the characteristic mass spectra. This is achieved via three chief functions:
01:19Mass Analyzers: Common Types
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...
01:19Inductively Coupled Plasma–Mass Spectrometry (ICP–MS): Overview
In inductively coupled plasma–mass spectrometry (ICP–MS), an inductively coupled plasma (ICP) torch is used as an atomizer and ionizer. Solid samples are dissolved and volatilized before being introduced into the high-temperature argon plasma, while solution samples are nebulized and passed through the high-temperature argon plasma. Plasma dissociates the analytes and ionizes their component atoms to form a mixture of positive ions and molecular species. The positive ions are then passed on to...
01:21Atomic Absorption Spectroscopy: Lab
For AAS measurements, samples must be introduced as clear solutions, often requiring extensive preliminary treatment to dissolve materials like soils, animal tissues, and minerals. Common methods for sample preparation include treatment with hot mineral acids, wet ashing, combustion in closed containers, high-temperature ashing, or fusion with reagents.
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing nebulizer...
01:19Inductively Coupled Plasma Atomic Emission Spectroscopy: Principle
Inductively coupled plasma (ICP) is the most widely used plasma source in atomic emission spectroscopy (AES), also known as Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The ICP source, or torch, consists of three concentric quartz tubes with argon gas flowing through them. A spark from a Tesla coil initiates the ionization of argon, generating a high-temperature plasma.
The ions and electrons produced interact with the fluctuating magnetic field created by a water-cooled...
The ions and electrons produced interact with the fluctuating magnetic field created by a water-cooled...
01:29Atomic Emission Spectroscopy: Lab
AES is a powerful analytical technique, especially effective when used with plasma sources, producing abundant spectra in characteristic emission lines. The Inductively Coupled Plasma (ICP), in particular, yields superior quantitative analytical data due to its high stability, low noise, low background, and minimal interferences under optimal experimental conditions. However, newer air-operated microwave sources are emerging as promising alternatives that could be more cost-effective than...