LO 3 Flashcards
(49 cards)
X-radiation causes ______ in living cells
Biologic changes ; it adversely affects all living tissue
Our goal as dental radiogrpahers is to minimize _______ and maximize _______
- The amount of radiation recieved by the patient
- Maximize the benefits
The amount of x-radiation recieved by patients can minimized by _______
Using proper patient protection techniques
What should be considered when prescribing dental radiographs in an effort to minimize exposure?
- The number, type, and frequency
- Individual assessment of patient to determine what is necessary
What constitutes proper x-ray equipment (not safety equipment)?
- Complies with provincial and federal guidelines and includes:
- Filtration (inherent, added, total)
- Collimation
- PID
Describe inherent filtration
Takes place when the primary beam passes through the glass window, x-ray tube, insulating oil, and tube head seal. It is equivalent to 0.5 to 1.0 mm of aluminum - more filtration is needed
Filtration is necessary to _________
Absorb the low-energy x-ray photons before they hit their target
Describe added filtration
An aluminum disk is placed between collimator and tube head seal - results in higher energy more penetrating, more useful beam
Total filtration is _______
The sum of inherent and added filtration
Machines operating at or below 70 kVp require a minimum total of _____ aluminum filtration, while those operating above 70 kVp require a minimum total of _____ aluminum filtration
1.5; 2.5
A round collimator produces a _____ shaped beam of 2.75 inches in diameter
Cone
A rectangular collimator produces a rectangular beam slightly larger than a ______ film
2
________ is an extension of the x-ray tubehead used to direct the x-ray beam
Position-indicating device
Position-indicating devices can be conical, rectangular, or round, but the ______ shaps is no longer used due to excess scatter radiation
Conical
Rectangular and round PIDs come in 8 or 16 inch lengths; they are open and _______ lined
Lead
The _______ PID produces the least divergence of the x-ray beam
Long
What should be done to the PID and tubehead for infection control purposes?
Cover with plastic barriers and change for each patient
What 6 factors impact patient exposure?
- Thyroid collar
- Lead apron
- Image receptors
- Beam alignment devices
- Exposure factor selection
- Proper technique
Thyroid collars are recommended for all ________ exposures, but not ________ exposures
Intraoral; extraoral
Thyroid collars are placed around the patient’s ________ and protect the thyroid from ________
Neck; scatter radiation
Thyroid collars are placed around the patient’s ________ and protect the thyroid from ________
Neck; scatter radiation
Lead aprons are placed over the patient’s chest to protect ________ and ______ from scatter radiation
Reproductive organs; blood-forming tissue
Why should lead aprons and thyroid collars not be folded?
Creases may crack the lead, resulting in holes that can allow radiation
When placing the lead apron, the clinician should take care not to ______ in order to avoid cross contamination
Touch the apron with the same gloves used to place the film in the patient’s mouth