Radiation Protection Quiz to Final Review Flashcards
(99 cards)
1
Q
What is used to assess the impact of gonadal dose?
A
GSD: genetically significant dose
2
Q
Temporary sterility can occur in males and last as long as 12 months with a dose of _________?
A
2Gy
3
Q
What is the most pronounced effect of exposure within the first weeks of fertilization?
A
Prenatal death, very rare
4
Q
3 major considerations when constructing a radiology departments protective barriers
A
- location in institution
- barriers
- adjoining rooms
5
Q
What about location in the institution must be considered ?(protective barriers)
A
- basment, main floor, upper floor: kind of clients, size of elevators
- infrastructure in the existing or new department
6
Q
2 common materials for barriers
A
- lead
- concrete
7
Q
What can good communication with the patient do?
A
- Reduce anxiety and stress
- Increase chances of successful x-ray
8
Q
4 types of patient shield. Describe
A
- Flat Contact shield: made of lead strips 1mm thick. Most effective for AP
- Shadow Shield: radiopaque material hang over the area of clinical interest to cast a shadow in the primary beam over reproductive organs
- Clear Lead Shield: transparent lead. Organic material impregnated with 30% lead by weight
- Shaped Contact Shield: contoured to enclose the male reproductive organs
9
Q
Design of an x-ray room rules
A
- Adequate working space for tech
- SHOULD be self closing door, but MUST have “unauthorized entry prohibited” sign
- no one can enter the room without the tech knowing
- beam only directed towards primary barriers
- wall detectors must have primary shielding
- radiation must be absorbed as close to the patient as possible
- control booth and window are secondary barriers
- radiation must scatter at least twice before entering control booth
10
Q
Another name for bone marrow dose?
A
Mean marrow dose
11
Q
Calculating barrier thickness
A
- location of controlled vs. Uncontrolled areas
- max kVp
- distance from radiation source
- occupancy on other side of barrier
- use of unit or time tube is energized
- workload of unit
- intrinsic shielding (leakage)
12
Q
What happens if an exposure is taken and the SID is too short? Too long?
A
Too short: overexposed, may need to repeat
Too long: underexposed, may need to repeat
13
Q
Lead apron specs for pregnant staff
A
90% attenuation at 75 kVp
14
Q
Controlled areas maximum exposure according to SC35
A
20mSv/yr
15
Q
What must be considered about adjoining rooms? (Protective barriers) and 2 types of adjacent rooms
A
- amount of time occupied
- type of occupancy
- controlled
- uncontrolled
16
Q
Irradiation of an unborn fetus increases risk of ________ and _______ effects.
A
- somatic
- genetic
17
Q
0.1mm lead =
A
- 0.5mm steel
- 1.2mm glass
- 2.8mm gypsum
- 19mm wood
18
Q
Use factors (from chart)
A
Primary Barriers:
U=1: full use, floor of radiation room, walls near upright detector, any walls/door/ceiling exposed to direct beam
U=1/4: partial use, door and wall areas not normally exposed to direct beam
U=1/16: occasional use, ceiling areas not normally exposed to direct beam
Secondary Barriers:
U=1: full use, scatter emerges in all directions
19
Q
Who do you contact if the patient in unsure about pregnancy status
A
Referring physician
20
Q
Most common SIDs for technique charts in Canada?
A
100, 110, 150, 180cm
21
Q
ESE
A
Entrance skin exposure
22
Q
When are the ovaries most radiosensitive? Least radiosensitive
A
Fetal stage, childhood, and after approx. 30yrs old until menopause
Least radiosensitive from 20-30 yrs old
23
Q
7 methods to reduce patient dose
A
- shielding
- collimation
- technical factors
- Quality control
- equipment
- communication
- filtration
24
Q
What is included in a Radiation survey report?
A
- Schematic of location, equipment, booth, and surrounding areas
- Equipment identification and type of tube support
- Observation of electrical and mechanical operation
- Actual or estimated total workload
- Result of radiation readings, both in and outside of controlled area
- Estimate of potential exposures
- Assessment of equipment, techniques, DRLs, restraints, filtration
- recommends improvements
25
What is the first and most important step in gonadal protection?
Collimation
26
Most genetic mutations are _______?
Recessive traits: both male and female must have the gene for it to be produced
27
Primary barrier materials
- Lead bonded to sheet rock or wood panelling
- Concrete, cinder blocks, or brick
1/16th" lead = 4 inches of brick
0.4mm lead = 24mm concrete
28
What is the role of the responsible user?
- Monitor and manage safety programs
- Implement image quality assurance program
- Oversees equipment safety and performance reports
- ensure equipment is used properly
- etc.
29
What is the occupancy factors? (T)
Takes into account the time that the space behind the barrier is occupied
30
SC 35 guidelines to exposing a pregnant patient
- exposure should be as low as possible
- shield if possible
- patient should be positioned prone- gets rid of softer rays
- don't use x-rays to see position of fetus
- well collimated, well shielded, AP/PA and lateral views only
31
3 types of PBL
- Aperture Diaphragm
- Cones
- Cylinders
- (Variable Aperture Collimator)
32
Protective staff clothing should be tested ________ and must be tested ________
Should: semi-annually
Must: annually
33
ColEfD
- collective effective dose
- used when a population has been exposed by a radiation accident
- EfD of an individual x # of people
34
What things are taken into account when measuring fetal dose?
-x-ray unit used
-projection taken
-#of images
-exposure factors used
-SID
-patient measurements
For fluoro and spot films: also exposure time
35
Secondary barrier materials
- gypsum
- glass
- lead-infused acrylic
36
Who is ultimately responsible for radiation safety of the entire facility?
The owner
37
NCRP
National Council on Radiation Protection
| -US corporation, determines how ICRP recommendations are incorporated into the US radiation protection criteria
38
What does quality control do?
Ensures production of optimal images
39
Uncontrolled area maximum exposure
1mSv/yr
| -pediatrics 0.30mSv/yr
40
Purpose of radiation surveys?
Ensures the x-ray and auxiliary equipment is working within SC35 standards and adhered to radiation protection act of alberta
Ensured proper equipment installation and provides max radiation protection for everyone
41
4 major concerns in radiology and fetus exposure are?
- congenital abnormalities
- spontaneous abortion
- metal retardation
- childhood malignancy
42
Thickness of a barrier depends on_______?
- distance between the barrier and radiation source
| - where the tube is situated when energized: upright, table, x-table
43
What is workload and Workload formula
mAs x (days/week) x (patient/day) x (films/patient)
Weekly radiation use of the unit (mA-min/wk or mAs/wk)
44
What is ESE?
Absorbed dose to the most superficial layer
45
EqD
- Equivalent Dose
| - the biological effect of radiation type R having a radiation factor WR
46
What is use factor?
Fraction of workload when the beam is on and directed towards a barrier
47
How much mA-min/wk is classed as a busy radiology room? Slow room?
Busy: greater than 500mA-min/wk
Slow: less than 100mA-min/wk
48
When are primary barriers required?
Whenever the primary beam is directed at a structure
49
Rules for staff protection
- Decrease time in room
- Increase distance from tube and patient
- Always use shielding
- Never stand in the primary beam
- ALARA also applies to our exposure
50
What is the greatest radiation hazard to the tech?
Patients
51
What is an uncontrolled area?
- occupied routinely by other staff/general public
| - bathroom, waiting room, change room
52
Permanent sterility in a males and females is most likely to occur with a dose of _______?
5-6Gy
53
What is GSD?
The EqD that can bring about genetic injury
54
7 methods to reduce patient dose
- Shielding
- Collimation
- Technical Factors
- Quality Control
- Equipment
- Communication
- Filtration
55
What happens if a fetus is irradiated in the first 2-12 weeks of development?
- skeletal and organ abnormalities
- central nervous system abnormalities
- neonatal death of abnormalities are severe enough
56
What is the ten-day rule?
X-rays should be taken in the ten-day period after menstruation begins because there is a low probability of pregnancy
57
EfD for occupational radiation exposure
- Whole body: 20mSV
- Eyes: 150mSV
- Skin, hand, and other organs: 500mSV
58
Minimum lead required in aprons
0.25mm
59
Occupancy Factors (from chart)
T=1: offices, labs, wards, nursing stations, living quarters, any other area that is normally occupied while the tube is energized
T=1/2: patient examination and treatment rooms
T=1/5: corridors, patient rooms, staff lounges, staff restrooms
T=1/8: corridor doors
T=1/20: public restrooms, vending areas, storage rooms, outdoor sitting areas, patient holding areas
T=1/40: outdoor areas with pedestrian or vehicle traffic, parking lots, drop-off areas, stairways, closets
60
Types of stationary barriers
- Primary barrier: absorbs primary beam
| - Secondary barrier: absorbs misdirected scatter and leakage
61
3 ways patient dose can be established?
- ESE/ESD
- Gonadal dose
- Bone Marrow Dose
62
What are dose limits?
Dose of radiation that is not expected to produce a significant effect
63
Ways to protect staff from exposure
- mobile walls
- bucky slot shielding device
- image intensifier curtain
- radiologist
64
7 factors that need considering when determinin necessary shielding for a DI room
- Primary or secondary barriers
- Distance from radiation source (D)
- Occupancy Factor of the area (T)
- Controlled or Uncontrolled areas
- Workload (W)
- Maximum and average tube potential and output
- Use Factor (U)
65
3 types of radiation that may be in an x ray room
- scatter
- leakage
- primary
66
All radiographic rooms MUST have a detailed floor plan that indicates
- location of control panel: dimension, shape, size, location
- location of the equipment within the room
- range of movement of the tube
67
What is the outcome if an exposure is taken at an SID that is too short?
Overexposed, may need to repeat
68
2 methods to determine ESE?
- Nomogram: graph
| - Calculations
69
Ideal kVp and mAs combo?
High kVp, low mAs
70
Another name for use factor?
Beam direction factor
71
What is used for the average kVp calculations of a room?
100kVp
72
Who calculates fetal dose after all the info is supplied to them?
Medical physicist
73
What is the purpose of protection standards groups?
To help to form recommendations for EfD and EqD
74
ESE helps the medical physicists approximate the fetal dose based on several factors (list factors)
- kVp
- mAs
- SID
- Beam filtration
- tube output per minute (in fluoro)
75
Two types of movement?
Voluntary and involuntary
76
Minimum amount of lead in protective equipment?
- Aprons: 0.35mm
- Shielded barriers: wall (0.3-2.0mm) hanging (0.5mm)
- Gloves: 0.25mm
- Glasses: 0.35
- Thyroid collars: 0.5mm
77
Maximum dose for fetus for entire pregnancy?
4.0mSv
78
ICRP
International Commission on Radiologic Protection
| -international authority regarding the safe use of ionizing radiation
79
TEDE
- total effective dose equivalent
- lifetime effective dose
- age in years x 10mSV
80
9 Safety equipment requirements from SC 35
1. Warning signs
2. Markings
3. Mechanical stability
4. Indicator lights
5. Indication of loading factors
6. Irradiation Control
7. Controlling Timer
8. X-ray tube shielding
9. X-ray beam filtration
81
How is the optimum technique for a patient determined?
- patient thickness
| - composition
82
UNSCEAR
United Nations Scientific Committee on the Effects of Atomic Radiation
- provides help for radiation guidelines
- evaluates human and environmental ionizing radiation exposures
83
NRC
Nuclear Regulatory Commission
84
Types of radiation and how to calculate them
- primary radiation: total primary = mR/mAs x mA x time
- Scatter (secondary): mR @ patient x 0.1% @ 1m
- Leakage (secondary): must never exceed 1mGy/hr OR 100mR/hr @1m
85
NAS/NRC-BEIR
National Academy of Sciences/Nation Research Council Committee on Biologic Effects of Ionizing Radiation
-advisory group that reviews studies of biological effects of ionizing radiation and risk assessments
86
Shielding plans should take into consideration what 2 things?
- advances in radiation technology
| - ALARA becoming stricter
87
What is the main priority of department design and safety?
-to protect the people from radiation exposure above current exposure limits
88
EfD
- Effective dose
- the biological effect of radiation on tissue types. Tissue having a radiation weighting factor WT
- measured overall risk of exposing body to radiation
89
Doses higher than ______ may deplete mature sperm (maturation depletion)
0.1Gy
90
10 specific radiographic equipment rules from SC 35
1. Radiation output reproducibility: same exposure 10 times w/same output
2. Radiation output linearity: different combos of mA and time
3. Irradiation switch
4. Automatic exposure control
5. Current time product limit
6. Accuracy of loading factors
7. Minimum irradiation time capability
8. Beam limiting devices
9. Radiation/light field alignment
10. Focal spot marking
91
What is the purpose of filtration?
'Hardens' bean by absorbing low energy photons, reduces patient dose
92
After puberty, doses as low as _______ may cause suppression and /or delay of menstruation?
0.1Gy
93
What is a controlled area?
- immediate areas where x-ray equipment is used
- occupied by monitored personel
- procedure rooms and control booth
94
Doses of _______ can cause temp. sterility in females?
2Gy
95
What is bone marrow dose?
Average radiation dose to all active bone marrow
96
Distance of the barriers depends on _________
The type of exposure the barrier receives
97
When calculating shielding, do we take into account the scatter from the patient?
No
98
4 methods to evaluate for and protect potential early pregnancies
- questions
- signs on doors and in change rooms
- elective bookings
- ten-day rule
99
What is the major contributor to gonadal dose?
Medical x-rays
