Xray - Week 2 PP Flashcards
Importance of Dental Images
In dentistry, dental images enable the
dental professional to identify many
conditions that may otherwise go
undetected and to see conditions that
cannot be identified clinically.
Many dental diseases and conditions have no clinical signs or symptoms and may go undetected without the use of dental images.
Uses of Dental Images
- Detect lesions
- Confirm or classify suspected disease
- Localize lesions or foreign objects
- Provide information during dental procedures
- Evaluate growth and development
- Illustrate changes secondary to caries,
periodontal disease, trauma - Document the condition of a patient
- Aid in development of a clinical treatment plan
Dental Assistant’s Role for Xrays
- The dental assistant must have a thorough knowledge and understanding of the importance and uses of dental imaging
- Dental imaging enables the dentist to see
conditions that are not visible in the oral cavity - The dental assistant must understand the
fundamental concepts of atomic and molecular structure and have a working knowledge of ionizing radiation and the properties of x-rays - Radiation used to produce dental
radiographs has the capacity to cause
damage to all types of living tissues - Any exposure to radiation, no matter how
small, has the potential to cause biologic
changes to the operator and the patient - The dental assistant must have a thorough understanding of the characteristics of radiation to minimize radiation exposure to both the dental patient and the operator
Biological Effects of X-Radiation
Short-Term and Long-Term Effects
* Radiation effects can be classified as either short-term or long-term effects.
* After the latent period, effects that are seen within minutes, days, or weeks are termed short-term effects.
* Short-term effects are associated with large amounts of radiation absorbed in a short time (e.g., exposure to a nuclear accident or the atomic bomb). Acute radiation syndrome (ARS) is a short-term effect and includes nausea, vomiting, diarrhea, hair loss, and hemorrhage.
Short-term effects are not applicable to dentistry.
Various Effects of Radiation
Effects that appear after years, decades, or
generations are termed long-term effects.
Long-term effects are associated with small
amounts of radiation absorbed repeatedly over a long period.
Repeated low levels of radiation exposure are linked to the induction of cancer, birth abnormalities, and genetic defects.
Genetic Effects
Genetic effects are not seen in the
irradiated person but are passed on to
future generations.
Genetic damage cannot be repaired.
Radiation Effects on Tissues & Organs
In dentistry, some tissues and organs are designated as “critical” because they are exposed to more radiation than others during imaging procedures.
A critical organ is an organ that, if damaged, diminishes the quality of a person’s life. Critical organs exposed during
dental imaging procedures in the head and neck region
include the following:
1. Thyroid gland
2. Bone marrow
3. Skin
4. Lens of the eye
ALARA Concept
ALARA concept means as low as reasonably
achievable
◦ Every possible method of reducing exposure to radiation
should be employed
Personal Monitoring Dosimeter
Given to health care professionals exposed to radiation and monitored by Health Canada. It is linked to your Social Insurance Number. It tracks the amounts of radiation you are exposed to. If you go above the recommended amount, Health Canada will contact you to investigate.
Radiation Monitoring
- Equipment monitoring
◦ Dental x-ray machines must be monitored for leakage radiation - Personnel monitoring
◦ A radiation monitoring badge can be worn at waist level when taking images
◦ It is mailed along with a control badge to the monitoring company once a month for evaluation
Safety Code 30
Safety Code 30 indicates personnel only need to use dosimeters in certain circumstances, however, Alberta’s Occupational Health and Safety Code (OHS Code) requires all workers who use or are exposed to radiation to use
them.
* In Alberta, we follow the OHS Code as it takes precedence. S. 291.5 requires that “a worker who uses or may be exposed to radiation through the use of any ionizing radiation equipment” must use a monitoring device.
Prescribing Dental Images
The first important step in limiting the amount of x-radiation received by a dental patient is the proper prescribing, or order, of dental images.
The person responsible for prescribing dental images is the dentist. The dentist uses professional judgment to make decisions about the number, type, and frequency of dental images
Proper Equipment
Another important step in limiting the amount of xradiation a dental patient receives is the use of proper equipment. The dental x-ray tube head must
be equipped with appropriate aluminum filters, a lead collimator (rectangular), and a position indicating device.
Compared with a short (8-inch) position indicating device (PID), the longer (16-inch) PID is preferred because it produces less
divergence of the x-ray beam
Rectangular Collimeter
Collimators must now be rectangular instead of circular.
* Safety Code 30 s. A.3.2.2, 2 states
“Rectangular collimation of the X-ray beam
must be used, except in occlusal protocols, as it significantly reduces the dose to the patient compared to circular collimation.”
Patient Protection measures during exposure
Patient protection measures are used before and during x-ray exposure.
A thyroid collar, lead apron, digital sensors or fast film, and beam alignment devices are all used during x-ray exposure to limit the amount of radiation received by the patient. Proper selection of exposure factors and good technique further protect the patient from excessive exposure to x-radiation.
Thyroid collar
The thyroid collar is a flexible lead shield that is placed securely around the patient’s neck to protect the thyroid gland
from scattered radiation The lead prevents radiation from reaching the gland and protects the highly radiosensitive
tissues of the thyroid.
It is recommended for all intraoral exposures
It is not recommended for extraoral exposures
The lead apron
The lead apron is a flexible
shield placed over the patient’s
chest and lap to protect the
reproductive and bloodforming tissues from scatter radiation; the lead prevents the
radiation from reaching these
radiosensitive organs Use of a
lead apron is recommended
for both intraoral and extraoral
exposures.
Beam Alignment Device
Stabilizes the receptor in the mouth and
reduces the chance for movement
◦ Eliminates the need for the patient to hold the
receptor in position with a finger, reducing
unnecessary exposure
Image Receptors
Compared with traditional film radiography, digital image receptors require less radiation exposure to the patient. The use of a digital receptor is the most
effective method of reducing a patient’s radiation exposure.
The lowered absorbed dose is significant with regard to patient protection from excessive radiation
Exposure Factor Selection
Adjustment of kVp, milliamperage, and time
settings on the control panel to limit the amount of x-radiation exposure received by the patient
On most units, the kilovolt peak and milliamperage are preset by the manufacturer and cannot be
adjusted
Proper Technique
The proper technique helps create a diagnostic image and reduce the amount of exposure a patient receives. Images that are nondiagnostic must be retaken; this results in additional exposure of the patient to radiation.
The re-exposure of an image, or retake, must be avoided at all times.
To produce diagnostic images, the radiographer must have a thorough knowledge of the techniques used in dental imaging
After Exposure
Proper receptor handling
◦ Artifacts caused by improper film handling result in nondiagnostic films
* Proper film processing/image retrieval
◦ Improper film processing may require retakes, needlessly exposing the patient to excess xradiation
Operator Protection
- The dental radiographer must use proper
protection measures to avoid occupational
exposure to x-radiation (e.g., primary radiation, leakage radiation, scatter radiation). - The use of proper operator protection techniques can minimize the amount of radiation that a dental radiographer receives.
- Operator protection measures include following protection guidelines and using radiation monitoring devices.
