Midterm Flashcards
radiation detection instrument operates in the ____ or ____ mode
radiation detection instrument operates in the PULSE or RATE mode
the practice of measuring the intensity of radiation
dosimetry
the radiation-measuring devices
dosimeters
designed to detect or measure radiation
radiation detection instrument
5 radiographic detectors
photographic emulsion
gas filled detectors
scintillation detectors
thermoluminescenct detectors
optically stimulated detectors
earliest radiation detection device
it is limited range, sensitive and energy dependent
personnel monitoring and emulsion imaging
photographic emulsion
it is used widely as a device to measure radiation intensity & to detect radioactive contamination
gas filled detectors
3 types of gas filled detectors
ionization chamber
proportional counter
geiger-muller counter
in general, the larger the chamber, the more gas molecules are available for ionization and, therefore the more sensitive the instrument
gas filled detectors
the instrument of choice for measuring radiation intensity
it is wide range, accurate and portable
survey for radiation levels 1mR/hr
ionization chamber
it is used for contamination control in nuclear medicine laboratories
it is limited to 100 mR/hr and portable
survey for low radiation levels and radioactive contamination
geiger-muller counter
it has the ability to distinguish between alpha & beta radiation
it is laboratory equipment, accurate and sensitive
array of small quantities of radionuclides
proportional counter
basis for the gamma camera and it is used in the detectors arrays of CT imaging system
it is used as IR in digital imaging system
it is limited range, very sensitive and stationary or portable instruments
scintillation detectors
when exposed to ionizing radiation the crystals in TLD undergo structural changes that remains essentially stable until the crystal is heated. When heated, the stored energy is released as light
thermoluminescence dosimetry (TLD)
its uses as a personnel monitoring, stationary and area monitoring device
thermoluminescence dosimetry
developed by Laundauer in late 1990s
more sensitive than TLD, reanalysis, wide dynamic range and excellent long term stability
optically stimulated luminescence dosimetry
3 ways of estimation of patient dose
entrance skin dose/ESE
mean marrow dose/MMD
genetically significant dose/GSD
x-ray exposure to the skin and is most often is referred to as the patient dose
entrance skin dose/ESE
3 methods of estimation of ESE
TLD
nomogram
know the output intensity for at least one operating condition
average radiation dose to the entire active bone marrow
estimated from ESE
mean marrow dose/MMD
average gonadal dose given to members of the population who are of childbearing age
genetically significant dose/GSD
acceptable techniques in mammography
screen film
digital mammography
__________ examination should not be performed when there is no precise medical indication
ROUTINE EXAMINATION should not be performed when there is no precise medical indication
in hospital admission, ______ _____ examinations should not be performed for routine hospital admission when no clinical indication of disease is found
CHEST XRAY EXAMINATIONS should not be performed for routine hospital admission when no clinical indication of disease is found
in pre employment physical, _______ and _____ _____ xray examination are not justified
in pre employment physical, CHEST and LOWER BACK xray examination are not justified
in periodic health examination, it should not include ______ examination for asymptomatic patient, especially fluoroscopic examination
in periodic health examination, it should not include XRAY examination for asymptomatic patient, especially fluoroscopic examination
in emergency room CT, __________ must be controlled
in emergency room CT, OVERUTILIZATION must be controlled
3 highest repeat rate examination
lumbar
thoracic
abdomen
higher ____ : reduces ____
reduced patient dose
too low contrast
higher kVp : reduces mAs
reduced patient dose
too low contrast
it is essential to good radiographic technique
proper collimation
general radiography have ___ speed system
general radiography have 400 speed system
results of fast screens
quantum mottle
two types of specific area shielding
contact shield
shadow shield
shields that are flat & are placed directly on the patient’s gonads
contact shield
shields that is suspended over the region of interest
shadow shield
shadow shield is applied in ________
shadow shield is applied in SURGERY
