Nukes Q/A Flashcards
What is ionizing radiation?
high energy radiation given off from radioactive materials
What are four types of ionizing radiation
alpha particle beta particle gamma particle neutron
Long term effects of radiation interaction with cells
changes in mitochondrial and nuclear DNA irreparable damage and mutations which can be propagated in a cell line
Maximum dose no longer increases effect (e.g. complete hair loss)
deterministic effect
Latency period is required before effects become evident
stochastic effect
Acute effects of excessive radiation
Deterministic effects
Probabilistic effects of radiation exposure
stochastic effects
Probability of disease at any dose level and the probability increases with dose
Stochastic effect
Examples of direct deterministic effects of radiation:
erythema, hair loss, nausea/vomiting, aplastic anemia
Is radiation sickness a deterministic or stochastic effect?
deterministic
What device measures radiation intensity?
ionization chamber
What is the unit used to measure radiation intensity?
milliRoentgen per hr (mR/hr)
How many rads are in 1 Gy?
100rads = 1Gy
In nuclear medicine what does the absorbed dose depend on?
-t1/2 of radiopharmaceutical -Biological t1/2 of radiopharmaceutical -% taken up by body -Type of radiation emitted by radiopharmaceutical
What is the radiation weighting factor
used with equivalent dose: Photons 1 Electrons 1 Protons 2 Alpha 20 ←most damage Neutrons varies with E
What is the NRC limit for patient release?
7 mrem/hr
Is food or drink allowed in the hot lab?
no
Can you prop the door open to the hot lab
no
What dose range is allowed for a dose calibrator?
+/- 20%
How is constancy of a dose calibrator measured?
Reference source (57co, 133Ba, 68Ge, or 137 Cs) is placed in the dose calibrator, should be within 10% on DAILY readings
How is linearity checked?
Decay method or shield method. Measured activities of Tc-99m plotted on a semilogarithmic graph either over time or using lead sleeves of increasing thickness (to save time)
QC time intervals for a dose calibrator
Constancy = daily Linearity = quarterly Accuracy = annually Geometry = after repair or moving instrument Calibration = annually
What should beta emitters be shielded with?
Glass or plastic to avoid bremsstrahlung xray exposure
dose calibrator
(gas filled detector used to measure the radiopharmaceutrical dose before administering it to the patient)
weekly
What does Nuclear Regulatory Commission (NRC) regulation 10 CFR Part 35 deal with?
10 CFR Part 35 is titled “Medical Use of By-product Material,” and is a key regulation for Nuclear Medicine Authorized Users and physicians performing radiation therapy.
Familiarity with 10 CFR Part 35 is particularly important for individuals who use radioactive materials for diagnostic or therapeutic purposes. Requirements for practice, training, experience, and related information is given.
According to BEIR VII, cancer incidence increases by approximately how much? (1 Gy = 100 rad)
0.08% per rad (8% per Gy)
Cancer risk estimates are often quoted simply as as 0.08% per rem for excess cancer incidence and 0.04% per rem for excess cancer death, making no distinction in the risk estimate for males and females. These values are based on the results of the BEIR V (1990) report, which preceded BEIR VII (2006) on this topic. Also, many sources report the risk units in “per rem” rather than “per Gy” as is done in the BEIR reports.
a patient administered radioactive material is released, what is the dose is okay for the caregiver to receive?
5mSv
what happens to SUV measurement if th epatient weight is incorrectly entered as higher than actual patient weight?
SUV is overestimated
administered activity must be within what percentage of the prescibed activity?
20%
what is used as a source in PET QC for uniformity?
Germanium-68 or sodium 22
Germanium-68 has a long half life of approximately 280 days and decays to Ga-68 via electron capture
