Lesson 1 (MIDTERM) Flashcards
Designed to detect or measure radiation
Radiation Detection Instrument
Radiation Detection Instrument . Presence of radiation (tickling, chirping, beeping sound)
Pulse mode
Operate in the pulse or rate mode
Radiation Detection Instrument
Radiation Detection Instrument. the practice of measuring the intensity of radiation
Dosimetry
Rate Mode
- measure intensity of radiation
- accumulate signal
- mGya
- Gya
Pulse Mode
- mGya/hr
- mR/hr
- Gya/hr
- detect
The earliest radiation detection device
Photographic Emulsion
It is used to indicate the presence of radiation
Radiation Detection Instrument
Photographic Emulsion. Uses
- personnel monitoring
- emulsion imaging
It is used widely as a device to measure
radiation intensity & to detect radioactive
contamination
Gas-Filled Detectors
Enumerate the radiation detection & measuring device
- Photographic
- Gas-filled Detectors
- Thermoluminescence Dosimetry
- Optically-Stimulated Luminescence Dosimetry
- Scintillation Detection
Radiation Detection Instrument. the radiation-measuring devices
Dosimeters
Ionization Chamber. Characteristics
wide range, accurate & portable
Photographic Emulsion. Characteristic
- limited range
- sensitive
- energy dependent
Gas-Filled Detectors. In general, the _____ the chamber, the _____ gas molecules are available for ionization and, therefore the _____ the instrument.
larger, more, more sensitive
Ionization Chamber. Uses
survey for radiation levels 1 mR/hr or 10 µGy/hr
The instrument of choice for measuring radiation intensity
Ionization Chamber
Three types of Gas-Filled Detectors
o Ionization chamber
o Proportional counter
o Geiger- Muller counter
Proportional Counter. Characteristics
laboratory equipment, accurate & sensitive
It has the ability to distinguish between alpha & beta radiation
Proportional Counter
It is used for contamination control in nuclear
medicine laboratories
Geiger-Muller Counter
Scintillation Detection. Characteristics
limited range, very sensitive, & stationary or portable instruments
Geiger-Muller Counter. Characteristics
limited to 100 mR/hr & portable
Proportional Counter. Uses
assay of small quantities of radionuclides
Scintillation Detection. Materials
NaI:Tl or CsI:Tl
Geiger-Muller Counter. Uses
survey for low radiation levels & radioactive contamination
Basis for the gamma camera
Scintillation Detection
It is used in the detectors arrays of CT imaging
system
Scintillation Detection
_____ is used as _____ in digital imaging system
Scintillation Detection; IR
_____ Discovered in the _____ at the _____.
Thermoluminescence Dosimetry (TLD)
1960
University of Wisconsin
Thermoluminescence Dosimetry (TLD). Uses
personnel monitoring, stationary & area monitoring
When exposed to ionizing radiation the crystals in _____ undergo structural changes that remains essentially stable until the crystal is _____. When _____, the stored energy is released as _____.
Thermoluminescence Dosimetry (TLD)
Heated
Light
OSL Developed by _____ in late _____
Laundauer 1990s
Thermoluminescence Dosimetry (TLD). Materials
Lithium Fluoride, Calcium Fluoride, Lithium Borate & Calcium Sulfate
Optically Stimulated Luminescence Dosimetry (OSL). Material
Aluminum oxide (Al2 O3 )
Thermoluminescence Dosimetry (TLD). Characteristics
wide range, accurate & sensitive
o as low as 5 mrad
o >10 rad
Thermoluminescence Dosimetry (TLD). Advantages
- Size
- Reusable
- Responds proportionately to dose
- Rugged
Optically Stimulated Luminescence Dosimetry (OSL). Enumerate step process
o Exposure to ionizing radiation
o Laser illumination
o Measurement of the intensity of stimulated light emission
Enumerate Advantages of OSL over TLD
- More sensitive – 1 mrad or 10 µGyt
- Reanalysis
- Wide dynamic range
- Excellent long-term stability
