Week 5 Flashcards
Why is the record of radiation exposure important in employment records for radiation workers?
It tracks exposure levels to ensure they are within safe limits and for compliance with safety regulations.
Under what circumstances is personnel dosimetry a requirement?
When radiation workers are likely to exceed 10% of the annual occupational EfD limit of 50 mSv (5 rem) in a year.
What is the primary function of a personnel dosimeter?
To indicate the working habits and conditions of diagnostic imaging personnel and measure occupational exposure to ionizing radiation.
What is the concept of area monitoring in radiation protection?
Area monitoring involves measuring radiation levels in a specific environment to ensure safety standards are met.
What are the advantages and disadvantages of optically stimulated luminescence dosimeters (OSLs)?
Advantages: Lightweight, durable, allows for reanalysis. Disadvantages: Measures exposure only at the location worn, exposure isnt immediately determined.
What is the sensitivity range of OSL dosimeters?
OSL dosimeters can accurately read exposures as low as 10 μSv.
How is exposure assessment conducted using different dosimetry devices?
Devices detect and measure ionizing radiation exposure, with periodic analysis and reporting of the data collected.
Why is a second dosimeter sometimes used, and where should it be placed?
A second dosimeter is worn beneath a lead apron at waist level when additional monitoring is required for fetal or extremity exposure.
What information can be interpreted from a radiation monitoring report?
It includes data about the occupational exposure measured, aiding in assessing if exposure is within regulatory limits.
How is occupational radiation exposure measured and monitored with dosimeters?
By detecting and measuring the quantity of ionizing radiation the dosimeter is exposed to over a period of time.
What role does control monitoring play in personnel dosimetry?
Control monitors are used as baseline references for assessing the validity of dosimeter readings in varying environments.
Why dont personnel dosimeters provide protection from radiation?
They are designed only to detect and measure ionizing radiation, not to shield or protect against it.
How do direct ion storage (DIS) dosimeters differ from other types?
DIS dosimeters use ion storage technology for real-time exposure monitoring and can be read instantly on-site.
What features make an optically stimulated luminescence dosimeter (OSL) popular?
Lightweight, durable, easy reanalysis capabilities, and accurate readings as low as 10 μSv.
Why is the placement of a personnel dosimeter important?
To accurately measure the radiation dose received by the most exposed parts of the body, such as the thyroid, head, and neck.
Where should the primary personnel dosimeter be placed during routine imaging procedures?
It should be attached to the front of the body at collar level, outside any protective apron.
What are the different types of personnel dosimeters?
Optically Stimulated Luminescence (OSL) dosimeters, Thermoluminescent Dosimeters (TLDs), Pocket Ionization Chambers, and Digital Ionization Chambers.
How is personnel monitoring managed for pregnant diagnostic imaging personnel?
The primary dosimeter is worn at collar level and a second is worn at the abdominal level.
What are the three types of gas-filled survey instruments and their appropriate uses?
Ionization Chambers for exposure measurement, Proportional Counters for alpha and beta radiation, and Geiger-Müller Detectors for detecting radioactive particles.
At what level does a personnel dosimeter detect and measure ionizing radiation?
It measures exposure to ionizing radiation that the wearer is exposed to over a period.
What are the limitations of the OSL dosimeter when assessing occupational exposure?
It measures exposure only in the area where it is attached and doesnt provide immediate exposure data.
What factors should not influence the performance of a personnel dosimeter?
Environmental factors like warm weather and humidity should not affect its performance.
What is the purpose of an extremity dosimeter?
To measure radiation exposure to the hands or extremities during procedures involving close proximity to the primary X-ray beam.
What are the desirable characteristics of an effective personnel dosimeter?
Lightweight, durable, able to detect and record small/large exposures, unaffected by environmental conditions, inexpensive, and easy to carry.
How do healthcare facilities implement the ALARA concept in personnel monitoring?
By issuing dosimeters when personnel might receive about 1% of their annual EfD limit in a month, approximately 0.5 mSv.
What do gas-filled detectors measure in relation to radiation?
They measure the quantity of electrical charge resulting from the ionization of gas or the rate at which the electrical charge is produced.
What are the advantages of Direct Ion Storage Dosimeters?
Instant access to data, lightweight and durable, can withstand being dropped or scratched.
Why is the proportional counter not used in diagnostic imaging?
It is primarily a lab instrument used for measuring alpha and beta particles.
What is the main disadvantage of pocket ionization chambers?
They cannot be used for long-term monitoring and must be charged before each use.
What are the key components of a pocket ionization chamber?
An ionization chamber with a built-in electrometer.
How are ionization chambers used in radiology for X-ray exposure measurement?
They are used to measure the radiation output from radiographic and fluoroscopic X-ray equipment.
What is the sensitivity range of OSL dosimeters for X-ray and gamma ray?
10 μSv (1 mRem) to 10 Sv (1000 rem).
What are the requirements for portable radiation survey instruments?
Portable, durable, reliable, interacts with radiation as tissue does, detects all common types of ionizing radiation, response not affected by radiation energy, cost-effective, calibrated annually.
Which professionals use ionization chambers for standard measurements required by health organizations?
Medical physicists.
What type of detector is used in Optically Stimulated Luminescence Dosimeters (OSLs)?
Aluminum oxide detector (Al2O3).
Which instrument is primarily used for area monitoring in nuclear medicine?
Geiger-Müller Survey Meter.
How does the sensitivity of OSL dosimeters compare to film badges and TLDs?
OSL is more sensitive than film badge and TLDs and is the 2nd most sensitive of the four common types.
What is a common use case for pocket ionization chambers?
For short-duration monitoring in high dose situations with an immediate readout.
What additional component must be calibrated along with ionization chambers for compliance in radiology?
The electrometer system must also be calibrated periodically.
What are the advantages and disadvantages of the ionization chamber-type survey meter (cutie pie)?
Advantages: Sensitivity ranges, used for radiation protection surveys. Disadvantages: Not very useful for diagnostic imaging using X-ray.
What makes the Geiger-Müller survey meter suitable for detecting small amounts of radiation?
It is highly effective in detecting radioactive nuclei or photons to small amounts of radiation and includes an audible signal.
What are the three filters used in OSL dosimeters?
Aluminum (Al), Tin (Sn), and Copper (Cu).
What must be done when a radiation worker changes employers?
A record of their cumulative dose should be transferred to the new employer.
How is a TLD read?
By heating the crystals, which releases stored photon energy.
What type of crystals are used in Thermoluminescent Dosimeters (TLDs)?
Lithium Fluoride (LiF) crystals.
How does radiation information get stored in Direct Ion Storage Dosimeters (DIS)?
Radiation ionizes the gas in the chamber, and the electric charge is stored in EEPROM until read out.
What is the typical usage term for an OSL dosimeter?
Up to 1 year, but commonly worn for 1 to 3 months.
How do proportional counters differ in their measurement capabilities compared to GM survey meters?
Proportional counters are used for measuring alpha and beta particles, whereas GM survey meters are used for detecting gamma radiation and X-rays.
What are the three categories of radiation survey instruments for area monitoring?
Instruments without a readout scale, with a readout scale, and ionization-chamber based.
What is a common type of detector used in radiation survey instruments for area monitoring?
A Geiger-Müller tube.
