Radiation Protection Flashcards
What is Gray (Gy)?
Absorbed dose
Air Kerma (Gya) definition and characteristics
- used to define radiation exposure or radiation delivered to a specific point
- indicates the amount of energy transferred to a mass of air by photons
- released in matter, mass, and materials
- preferred unit
- used to measure tube leakage
Gray (Gyt)
Amount of energy absorbed per unit mass of tissue
Sievert (Sv) definition and characteristics
- unit of equivalent dose
- considered the biological impact of the type and energy of radiation being used
- measures quantity of radiation received by radiation worker and populations
What is Wr?
weighting factor; r stands for type of radiation
What type of radiation are rad. techs. exposed to?
x-rays and gamma rays that have a r value of 1
What is the dose limits for the general public and students older than 18?
- 1 mSv per year for the general public and students older than 18
- 5 mSv for infrequent exposure
What is the dose limit for occupational exposed workers?
- 50 mSv for head to toe
- 150 mSv for eyes
- 500 mSv for skin, hands, and feet
ALARA and how it’s achieved
- as low as reasonably achievable
- use of close collimation
- high speed IRs
- filtration of primary beam
- avoiding repeats
- optimal kVp technique
What is the primary cause of repeats? What can be done to avoid this?
- poor communication
- be clear with directions and expectations
- talk to patient and watching them during exposure
What does correct filtration do? What is the material used for it?
- reduces exposure by absorbing low energy “unusable” x-rays
- aluminium
Pregnant Patient Precautions
- all females of childbearing age should be screened for pregnancy
- if they are pregnant, notify radiologist
- if procedure continues, discuss risks and benefits and have them sign a consent form
What exams deliver less than 10 mGy to embryo / fetus?
- head and chest exams
- head and chest CTs
- extremities
- thoracic spine
- skull
What exams deliver more than 10 mGy to embryo / fetus?
- pelvis and abdomen CT
- pelvis and abdomen exams with 3 or more views
- lumbar spine
- scoliosis
- fluoroscopic procedure
Who should hold an uncooperative patient?
- parent or family member
- hospital worker that is NOT occupationally exposed to radiation
Who should NOT hold an uncooperative patient?
- anyone under 18
- anyone who is pregnant
- any hospital worker who is occupationally exposed to radiation
What do personnel monitoring devices do and what are the two types? When are they exchanged?
- measures the amount of radiation dose received
- thermoluminescent dosimeter (TLD) and optically stimulated luminescence dosimeter (OSL)
- exchanged monthly or quarterly
Dosimeter locations
- worn at waist or chest level
- on a pregnant worker, a second one is at the waist level
- during a fluoroscopic procedure, the dosimeter is on the outside of the lead apron and thyroid collar
How do rad. techs. protect themselves from radiation?
- always wearing personnel monitoring devices
- the use of mechanical holding devices such as compression bands, sponges, sandbags, and tape
What are the 3 cardinal principles of radiation protection?
- time: minimizing the time of exposure
- distance: standing as far from the source as possible
- shielding: standing behind protective devices or in the control barrier booth
Primary radiation definition, travel pattern, and energy level
- x-ray beam that leaves the tube and is not attenuated except by air
- starts at tube target and expands into cone shaped beam; is predictable
- controlled by kilovoltage setting
Scatter radiation definition, travel pattern, and energy level
- scattered or created as a result of the attenuation of the primary bean by matter
- travels in all different directions
- less energy than primary beam
Remnant radiation definition, travel pattern, and energy level
- what remains of the primary beam after attenuation by matter
- continuation of primary beam
- pattern of intensity creates radiographic image
Where is the safest place to stand inside the fluoroscopy room?
behind the radiologist
