Principles of radiation protection Flashcards
What is the difference between therapeutic and diagnostic x rays?
Theraputic is used to teat, diagnostic is ued to determine ilnesss or inury
What are the four main aspects of radiaton safety?
- Patients shouldnt be subjected to unessesary radiographic procedures
- The patient must be protected from excessive raidation during exam
- Personnel within favility must be protected from expessive exposure during work
- Personnel and general public in vaccinity of such facilities require adequate protection
Are surgeons requried to have lead protection?
Yes, prior to scrubbing in
Why are repeat exposures problematic?
Unessesary radiation exposure (doubling your dose)
How do DI values help us evaluate an exposure?
Helps us determine whether the patient has recieved too much or too little radiation (compared to target value)
What are the 3 cardinal principles of radiation protection?
- Time
- Distance
- Shielding
How can we reduce the radiation time for patients?
By reducing the amount of x-ray exposure with floroscopy
(reciprocity does not apply)
How do we reduce the time of radiation exposure for personnel?
Shortening the length of time in the room
How do we reduce the distance for technologists
Standing as far away at a 90 degree angle to the source
Who does dose limits apply to?
The amount of radiation exposure that the general public or operator could recieve as a result of an exposure
What is the basis of the effective dose limiting system?
Malignancy
What are DL advisory groups?
They formulate risk estimates of somatic and genetic effects of irradiation
What group is the umbrella agency for world radiation protection?
International commission on radiological protection
What safety code do we have to follow in Canada?
Safety code 35 (from health canada)
What two agenices in Ontario are involved in radiologic protection/safety?
- Ministriy of health-HARP (healing arts radiation protection commision)
- Ministry of labour-occupational health and safety act
What is the unit of measurement for exposure?
Coulomb per kg (C/kg) or mR
Define exposure:
The number of ionizations in air
What is the unit for absorbed dose?
mGy
What is the unit for effective dose?
mSv
What is the annual dose limit for the memebers of the public?
(mSv)
1 mSv
What is the annual dose limit for radiation workers?
20 mSv
Who requires a personnel dosimeter (TDL,OSL)
Occupationally exposed personnel-anyone who is at risk of exceeeding public DL of 1 mSv
What does TLD stand for?
Thermoluminescent dosimeter
What does OSL stand for?
Optically stimualted lumenescence
Where are dosimeters worn?
At the waist level
How do we know where do put our dosimeter on our body?
It shows a picture on the dosimeter where it is supposed to go
If you are wearing a lead apron, where does the TLD go?
Under the lead apron, and additional TLD’s can be worn over the apron
Does the DL differ from men to women?
No, unless the woman is pregnant
What is the effective dose limit once pregnancy has been announced?
For a worker
4mSv for the remainder of the pregnancy
What is the recommended dose limit for technologists-in training and students?
1 mSv
Is there a varience in DL for individual organs?
No, except for the lens of the eye, which it recommends a limit of 150 mSv
Can you have 2 x-ray tests in the same room at the same time?
No
Which way should the x ray tube be facing for a cross table examination?
Away from the tech
If an individual’s extremities will be exposed to a large amount of radiation, should they have addiational dosimeters?
Yes, they should be worn at the those locations on the body
How long do dosimetery recorders need to be kept?
For the lifetime of the facility
If a person who is in need of support during an exam requires being held or supported, can the x ray tech provide this service?
No, you can get RTs, nurses, porters, ect.
When should mobile units be used?
Used only if the condition of the patient is such as to make it inadvisable for the examination to be carriered out normally
What is the minimum distance that a tech needs to be away from the x ray tube
(Unless wearing shielding or standing behind sheilding)
3 meters
Where should irradiation be controlled from?
The control panel located in a shielded area
Can radiographic cassettes be held hand by hand during an irradiation?
No
What defines unessesary radiation?
- Any radiation exposure that does not benefit a person in terms of diagnostic information obtained for the clinical managment of medical needs
- Any radiation exposure that dose not enhance the quality of the study
Who is ultimately responsible for radiation safety of of the facility?
The owner the facility
Who does the owner of the hospital delegate responsibilites to?
Technolgical manager who should be a radiation safety officer
Who can be a radiation safety officer?
- Doctors
- Physicists
Who dos the technological manager delegate responsibilites to?
The x-ray equipment operator
(must be a member of CMRITO and CAMRT registered)
Who does the x -ray equipment operator delegate thier responsibilites to?
-Operators in training
Can students have indirect supervision during training?
Yes, can be direct or indirect
