Radiation Protection and Legal Aspects Flashcards
What does radiation protection mean?
Related to protection of people (radiation workers, members of the public, and patients undergoing radiation diagnosis and therapy) against the harmful effects of ionizing radiation
True or False: Radon is found naturally in the ground?
TRUE
What are the guiding principles in relation to radiation protection?
- Justification
- Optimization
- Dose limitation
What does ALARA stands for?
As Low As Reasonably Achievable
“the radiation dose to the patient should be kept as low as possible”
What factors affect exposure time?
- patient age
- area to be evaluated
- imaging receptor
What does collimation limit?
the amount of radiation, both primary and scattered to which the patient is exposed
It limits the x-ray beam to the area of interest, reducing radiation exposure to surrounding tissues and improving image quality by reducing scatter radiation.
What does secondary space radiation entail?
affects living beings on Earth, interaction of primary radiation with the atmosphere, increases with the altitude, and it is 11% of background exposure
What is primary space radiation composed of?
Subatomic particles that are in a large quantity blocked by the terrestrial electromagnetic shield.
Can be especially harmful to astronauts.
What is the most radioactive food that contains internal radionuclides?
Brazil nuts are the most radioactive everyday food.
Which form of medical imaging contributes the highest percentage to the average radiation dose a person is exposed to, at 47%?
Computed tomography (CT)
Patient protection guiding principles: Justification
Benefit of the diagnostic exposure exceeds the risk of harm
Patient protection guiding principles: Optimization
Dentists should use all possible means to reduce unnecessary exposure to their patients, staff and themselves
Patient protection guiding principles: Dose limitation
The individual effective dose shall not exceed the limits recommended by the International Commission on Radiation Protection (ICRP)
What is the limit for human exposure to ionizing radiation to the general public?
1 mSv in 1 year
What is the dose limit for human exposure to ionizing radiation occupationally per year?
20 mSv per year, on average, over a period of 5 years, with a maximum of 50 mSv per year
What is the dose limitation to ionizing radiation for patients?
There is no defined dose limit; however much exposure allows correct treatment is recommended.
Make up about 9% of background exposure
Internal radionuclides
Makes up about 7% of background exposure
Terrestrial radiation
The main concern of oral and maxillofacial radiography is the _______________
unlikely chance of radiation-induced cancer
For a given x-ray beam, the intensity is inversely proportional to the _______________
square of the distance of the source
The optimal operating potential of intraoral dental x-ray units is between _______________
60 and 70 kVp
Recommended source to skin distance?
A 30cm source to skin is recommended but 20cm is acceptable.
What is the operator’s optimal position if they cannot leave the room?
If unable to leave the room, the optimal position would be at 45 to 90 degrees relative to the exit path of the primary beam and a distance of 6 feet from the patient.
Would you want a long or short PID to lower the irradiated area?
A long PID, to reduce the amount of divergent photon.
