Unit 2 Radiation Biology Flashcards
The time period between the effects of cumulative radiation and visible tissue damage is the
Latent period
Some of the somatic effects of long-term exposure to
ionizing radiation include
1. Genetic deformities.
2. Erythema.
3. Alopecia.
4. Blood dyscrasias.
All of the above
In offices employing film badges to monitor exposure, when should the badges be worn?
At all times when in the working
environment.
Which of the following statements are true about radiation?
Radiation us the emission of energy through space or a substance in the form of waves or particles.
Radiation travels at the speed of light.
Radiation is made from electrons traveling ata very high speed.
Which of the following statements are true of hard x- rays as compared to soft x-rays?
They are more penetrating
All cells in the body except reproductive cells are referred to as:
Somatic
The time that elapses between the exposure to ionizing radiation and the appearance of clinical symptoms is the:
Latent period
Effects of radiation that manifest themselves years after the exposure time are:
Long term effects
Examples of background radiation are:
Cosmic rays
Internal radiation
External radiation
Which of the following cells are most radiosensitive?
Red blood cells
Which of the following is the earliest detectable symptom of excessive exposure to radiation?
Erythema
The legal responsibility for all acts performed in the dental office is given to:
The dentist
The only person who should be in the path of the useful beam is the:
Patient
The amount of radiation a person receives:
Is accumulative in the entire body
A technique used to measure the operator’s exposure to radiation is:
For the operator to wear a radiation film
badge
The ALARA principle stands for:
Aw low as reasonably archievable
Which type of effect from radiation can be passed on to the offspring?
Genetic
All patients should be draped with a lead apron and
collar during dental radiographs.
True
Long term effects of radiation manifest themselves years after the exposure time
True
The radiation dose is the measure of ionization that is in the air.
False
Hair loss
Alopecia
When a dental radiograph is taken, all the x-rays reach the film and will not penetrate the skin or other body tissue
False
The primary cause of biological damage from radiation is
Ionization
Direct injury from radiation occurs when the x-ray photon
Strike critical cell molecules
Indirect injury from radiation occurs when the x-ray photons
Ionize water and form toxins.
According to the law of B and T, cells with a high reproductive rate are described as
Radiosensitive.
Which of these cells are most radiosensitive?
White blood cells
Which of these cells are most radioresistant?
Muscle cells
When the effect of a radiation exposure is observed in the offspring of an irradiated person, but not in the irradiated person, this is called the
Genetic effect
A dose–response curve indicating that any amount of radiation, no matter how small, has the potential to cause a bio- logical response is called
Nonthreshold
Each of the following is a factor that determines radiation injury EXCEPT one. Which one is the EXCEPTION?
Patient gender
According to the factors that determine radiation injury, based on age, who is the most radiosensitive?
A 6 year old
Which of the following is the correct sequence of events following radiation exposure?
Latent period, period of injury, recovery period
When a biological response is based on the probability of occurrence rather than the severity of the change, it is called a
Stochastic effect.
Which of these is considered a short-term outcome following radiation exposure?
Acute radiation syndrome
Full-term, low birth weight is possibly associated with radiation exposure to which of the following?
All of the above
During exposure of an intraoral dental radiograph, approximately how much smaller is the dose of radiation in the gonadal area than at the surface of the face?
0.0001
Each of the following is in the path of the x-ray beam during exposure of an intraoral dental radiograph on an adult patient. Which one, because of its relative
radioresistancy is NOT considered critical for dental radiography?
Spinal cord
The potential risk of a full mouth dental x-ray examination inducing cancer in a patient has been estimated to be
2.5 per 1,000,000 examinations.
What term best expresses comparisons between dental radiation exposures and natural background exposure?
Effective dose equivalent
Who has an ethical responsibility to adopt ALARA?
A. The dental assistant
B. The dental hygienist
C. The dentist
Based on the selection criteria guidelines, what is the radiographic recommendation for bitewing radiographs on an adult recall patient with no clinical caries and no high-risk factors for caries?
Every 24–36 months
Communication, working knowledge of a quality radiographic image, and education all aid in protecting the patient against unnecessary radiation exposure by
Reducing the risk of retake radiographs.
What is the minimum total filtration that is required by an x-ray machine that can operate in ranges above 70 kVp?
2.5 mm of aluminum equivalent
What is the federally mandated size of the diameter of the primary beam at the end of the PID (at the of the patient’s face)?
2.75 in. (7 cm)
Radiation protection from secondary radiation may be increased by the use of an aluminum filter and a lead collimator because the filter regulates the size of the
tissue area that is exposed and the collimator prevents low-energy radiation from reaching the tissue.
The statement is correct, but the reason is NOT correct.
Which of the following exposes the patient to less radiation?
16 in. (41 cm) rectangular PID
Which of the following contributes the most to reducing patient radiation exposure?
F speed film
During dental x-ray exposure, the lead/lead- equivalent thyroid collar with apron should be placed on
A. Children.
B. Females.
C. Males.
D. All patients.
Each of the following aids in reducing patient radiation exposure EXCEPT one. Which one is the EXCEPTION?
Slow-speed film
If a protective barrier is not present, what is the recommended minimum distance that the operator should stand from the source of the radiation?
6 ft (1.83 m)
Film badges, TLDs, and OSL and DIS monitors are used to
Monitor radiation exposure the dental radiographer may incur
The annual maximum permissible whole-body dose for oral health care personnel is
50 mSv.
The annual maximum permissible whole-body dose for the general public is
5.0 mSv
What is a symptom of x-ray dermatitis?
Erythema
The cells most sensitive to ionization radiation are
Reproductive cells
The best type of x-ray to penetrate tissue is
Hard rays (short wavelength/high frequencies).
Proper infection control techniques during radiographic procedures include:
- The technician should wear gloves while exposing
radiographs - The technician should wear gloves while processing
radiographs - The technician should wear a mask while exposing
radiographs - The technician should wear protective safety glasses
while exposing radiographs
Which number relates to a child’s dental film?
0
The size of the silver bromide crystals determines the:
Film speed or film sensitivit
The following are true about intraoral film packets:
- The film must be light tight
- The film must resist saliva seepage
- The film must be flexible
- The packets can either be double or single films
When the mandibular second premolar is radiographed, what portion of the film should beyond the occlusal plane?
1/8 inch
. The following are true statements about x-rays films:
- It is composed of a clear cellulose acetate
- It contains silver bromide crystal
- The crystals are suspended in a gelatin
A periapical film should show:
A. Entire tooth
B. 2/3 mm of periapical bone
C. 1/8 inch beyond the occlusal plane
D. All of the above
