Exam 3 - radiology Flashcards
veterinarians main use of radiation
diagnostic x-rays
OSHA
onsite services/consulting
decreased accidents in the US workplace
authority to fine facilities for potentially harming employees
authority to inspect facilities if owner is present
energy or elementary particles that can propagate through air and transfer energy to matter; energy in transit
energy or particles released during radioactive decay or produced artificially
radiation
radiation is of sufficient energy to eject electron; knock e- out of shell
localization is what matters - not that the total energy exchange is low
ionizing radiation
main type of ionizing radiation particles
list the other particles
electrons from accelerators
protons, neutrons, alpha particles, heavy charged particles
types of electromagnetic ionizing radiation
photons - xrays (extranuclear) & gamma rays (intranuclear)
how does ionizing radiation damage mammalian cells
deposition of ionizing radiation at or near DNA
radiation mostly causes ____ death but also causes ______
mitotic death (mitotic catastrophe)
apoptosis, autophagy, necrosis, senescence
skin changes - reddening of the skin due to vasodilation, erythema are due to ___ effects
early
birth defects and cancer are due to ____ effects following low doses of irradiation - job, environment, medical procedures
late - cells live and carry forward the damage, the cells during division die
spontaneous process by which the unstable atoms of an element emit or radiate excess energy in the form of particles or waves
radioactivity
energy deposited by radiation in mass of material at location of interest
absorbed dose
classify if the patient is radioactive or not after these procedures
radiographs
nucmed bone scan
pet CT
MRI
cobalt machines
no
yes
yes
no
machine yes, patient no
international unit
Gray
what are acute radiation syndromes (ARS)
acute effects following relatively high doses of whole-body irradiation
all ARS syndromes are preceded by ______
prodromal radiation syndrome (an effect soon after exposure) which is then followed by a latent period
name that syndrome:
death within 48-72 hrs
severe nausea/vomit
incoordination
resp distress
seizures, death
damage to endothelial cells (leakage/edema)
> 50 Gy
cerebrovascular syndrome (incapacitation syndrome)
name that syndrome:
death in 3-10 days
exposure > 7 Gy
nausea, vomit, diarrhea
dehydration, wt loss, exhaustion
septicemia, shock, electrolyte imbalance
gastrointestinal syndrome
prodromal signs of cerebrovascular syndrome
easy fatigability
prodromal signs of GI syndrome
anorexia
vomiting
lymphocytes undergo what type of cell death similar to salivary and lacrimal cells
apoptosis
name that syndrome:
no signs until latent period
3-8 Gy
destruction of BM stem cells = depletion of RBC, WBC, platelets
chills, fever, bruising, fatigue, oral ulceration and epilation
hematopoietic syndrome
when does death occur with hematopoietic syndrome
BEFORE ANEMIA
name that syndrome:
> 8 Gy
death ~ 130 days
pulmonary syndrome (rare)
name that syndrome:
beta or low energy photons (gamma)
inflam, erythema, dry/moist desquamation, hair follicle damage
immediate burns are thermal
latent phase
lethal or complicate recovery
cutaneous radiation injury (CRI)
the largest dose that humans can receive and survive is predicted to ____ subsequent cancers
double
Which ARS occurs shortly after whole body radiation exposure and may help predict patient outcome
prodromal syndrome
patient radiation dose use what units
Gray
radiation worker dose use what units
Sievert (Sv)
what is mostly used with veterinarinas and xrays, relative biological effectiveness (RBE) or tissue weighting factor?
RBE
The occupational dose for a radiation worker is:
5 rem (50 Sv) /year
natural external exposure
cosmic (e.g. sun)
terrestrial (varies by latitude and altitude - dose doubles with each mile above sea level)
mechanisms of internal exposure of radiation
ingestion/body tissue (thorium, radium, lead, K-40)
inhalation (radon gas)
The most significant reason for increased exposure to the general population over the last 30 years is
Increased use of radiation for medical procedures
what diagnostic procedure has the most mSV & rem
body CT then head CT
Currently, the primary concern and reason for establishing radiation dose limits for radiation workers is
prevent cancer
greatest personal risk?
smoking
fetal radiation exposure
0.5 rem (5 mSv)/ gestation period
0.05 rem/month
effects on embryo are not observed below ____ rem
10 rem
radiation during preimplantation 0-9 days results in…
embryonic death
radiation during organogenesis 10 days-6 weeks results in…
teratogenesis
radiation during fetal period 6wk -term results in…
growth retardation
radiation during fetal period 8-15(25) weeks results in…
mental retardation
what should a pregnant person do
declare their pregnancy, but have the right to not declare or to undeclare
ALARA responsibilities
time
distance
shielding
differences with high energy x-rays
shielded vault required
cannot be in room during treatment
