Patient Radiation Dose in Special Examinations
True of false:
The dose in CT is lower if the multi slice number is lower
False, the higher the multi slice number the lower the dose in CT
What imaging modalities are associated with no ionizing radiation?
Diagnostic ultrasound, magnetic resonance imaging.
ALARA
As low as resonably achievable
The incidence of spontaneous abortion in THE ABSENCE of radiation exposure is estimated to be in what range?
a. 5-10%
b. 10-25%
c. 15-30%
d. 25-50%
What does NCRP stand for?
National Counsel on Radiation Protection
(and measurements)
Acute skin effects from radiation exposure have been reported following __ exams.
a. lumbar spine
b. GI fluoro
c. mammography
d. angioinvterventional
d. angiointerventional
Performing routine x-ray exams without indication is acceptable for:
a. x-ray examination for tuberculosis
b. preemployment physicals
c. annual routine physicals
d. all of the above
e. none of the above
d. none of the above
Routine x-ray examinations should NOT be performed when there is no medical indication.
MMD
a. Median marrow dose
b. Mean marrow dose
c. Marrow medium dose
b. Mean marrow dose.
Numerous investigations strongly suggested that the principal response to high fetal irradiation after the first trimester can result in what?
The appearance of malignant disease during childhood.
What does ACR stand for?
American College of Radiology.
What radiation dose description is most important for x-ray mammography?
a. Entrance skin exposure
b. Glandular dose
c. Bone marrow dose
d. Any of the above
b. Glandular dose
What does the symbol Σ mean?
a. sigma
b. summation
c. both a & b
d. none of the above
c. both a & b
The sigma symbol means summation
Major Organogenesis
(During the __ week to __ weeks after conception)
The period of organogenesis during pregnancy is 2 to 10 weeks after conception.
What is the approximate fetal dose after a 3.5-minute barium enema fluoroscopic examination?
a. 2 rad (20 mGyt)
b. 5 rad (50 mGyt)
c. 15 rad (150 mGyt)
d. 50 rad (500 mGyt)
b. 5 rad (50 mGyt)
Name one imaging modality that has the highest relative radiation levels.
CT angiography, TIPS, PET-CT
What is the effective dose range for adult CT angiography?
a. 3 to 12 mSv
b. 10 to 30 mSv
c. 25 to 50 mSv
d. 40 to 60 mSv
b. 10 to 30 mSv
Approximately what percentage of the entrance skin exposure (ESE) is a glandular dose (Dg) for mammography?
a. 5%
b. 15%
c. 100%
d. 200%
b. 15% of the entrance skin exposure (ESE)
This term refers to an image blur that results from the size of the focal spot. A geometric tail on either side of a collimated x-ray beam.
A penumbra
What types of congenital abnormalities are most associated with irradiation in late organogenesis?
Neurologic deficiencies
Patient dose can be reduced by using:
a. faster screens
b. higher kVp
c. increased distance
d. both a. and b.
e. both a. and c.
d. both a. and b.
Faster screens, higher kVp and shielding help to lower patient dose.
What special examinations are challenging to quantify "dose distribution"?
Moving fluoroscopy
What is the approximate contribution of CT to total patient radiation dose?
Approximately half.
This term refers to the simplest way to measure patient dose.
a. Bone marrow dose
b. Gonadal dose
c. Entrance skin exposure
d. genetically significant dose
e. none of the above
c. Entrance skin exposure (ESE)
What types of congenital abnormalities are most associated with irradiation in early organogenesis?
Skeletal deformities.
The genetically significant dose for the general public is important because of the risk of:
a. damage to the fetus
b. increasing cancer rates
c. effects on the gene pool
d. all of the above
e. b & c only
b. effects on the gene pool