mosbys Flashcards
Which element of the hematopoietic system shows the earliest response to
radiation?
lymphocytes
What is the energy of a photon detected by PET?
511 kV
What does an image intensifier convert?
xray image into a light
What is afebrile?
without fever
What radiation interaction with matter occurs independently of atomic number?
compton
In what region of the pharynx is the pyriform sinus located?
hypopharynx
Patients that receive TBI at an early age may develop what secondary cancer?
osteochondroma
In order to reduce potential electron contamination, what is the preferred material
for custom blocks and compensator holders?
lucite
The adrenal glands are located at what thoracic level?
T12
Which photon interaction with matter involves direct photon interaction with the
nucleus?
pair production
The energy loss of MeV electron beams in water is approximately ___ MeV/cm
2
What does the back pointer determine?
beam exit point
In what age group in Hodgkin’s disease most common?
males and
females younger than 35/ over 60 (2 peaks)
A patient with a systemic infection risks ____ shock
septic
What kind of shock is associated with bacterial infections and its toxic byproducts?
septic
For which organ would the hypogastric lymph nodes be included in the treatment
field?
rectum
According to the law of Bergonnie and Tribondeau, ___ increases cell
radiosensitivity
high division rate
What is the process of cellular growth and development called?
proliferation
What is the threshold dose for radiation pneumonitis?
20-25 Gy
In RBE, the biologic effect of a particular type of radiation for a given dose is
compared to the biologic effects of ___ x-rays for the same dose.
250 kV
linear attenuation coefficient is expressed as
1/cm
what has a lower PDD, superficial or ortho
superficial
to prevent distant mets of prostate spread you need to include what in the tx field
common iliac
what would be an advantage of using the
wedged pair technique?
rapid dose fall off
Chondrosarcoma originates in what type of tissue?
osseous tissue
When treating the whole brain with opposing laterals, what is one way to minimize
beam divergence into the eye opposite the entrance port?
center the axis near the lateral canthus
What is the approx location of the external iliac lymph nodes?
1 cm lateral of the pelvic brim
What is the most cephalic portion of the normal stomach?
fundus
What is the last portion of the small intestine?
ileum
The field size is determined by which isodose line?
50%
Where is the head of the pancreas normally located?
sweep of the duodenum
where is the tail of the pancreas located
hilum of the spleen
What is the dose for prophylactic cranial irradiation for SCLC?
35-40 Gy
What imaging is not an example of functional imaging?
CT
Positron Emission Tomography (PET) is based on imaging with photons produced
by what?
annihilation of positrons by electrons
What is the actual physical dimensions of the tumor including regions of presumed
occult spread called?
tumor volume
Which has the highest frequency: 1) x-rays, 2) visible light, 3) microwaves, 4)
radiowaves
xrays
Dose is normalized to what in an SSD treatment technique?
Dmax
Dose is normalized to what in an SAD technique?
treatment depth
What does BSF depend on?
field size and beam energy
Which of the following effects describes the following: Increased dose equals
increased probability of effects?
stochastic
The blood count is depressed following a whole-body dose equivalent of at least
how many sievert?
0.25 Sv
How is damage to the cell being irradiated described?
somatic
What is used to modify the absorbed dose amount to account for the greater
damage inflicted by some forms of ionizing radiation?
weighting factor
Differential absorption is a result of which photon-tissue interaction?
photoelectric
Res ipsa loquitur
A case involving obvious negligence would be defined by the doctrine of
standard precautions
A system that emphasizes the placement of barriers between the health care worker
and the patient
medical asepsis
The process of eliminating as many organisms as possible by the use of water and
chemical disinfectants
Which of the following is used if there is any chance of coming in contact
primarily with products of the GI system of an infected person
enteric isolation
What causes blood to pool in peripheral vessels
neurogenic shock
What condition is caused by loss of a large amount of blood or plasma
hypovolemic shock
What is caused by infection that results in extremely low blood pressure
septic shock
butterfly injection
A smaller, easier-to-handle injection set that includes plastic projections on both
sides of the needle and may be used for venipuncture
venous catheter
is more flexible and easier to use than a needle or butterfly
is a combination unit with a needle inside a flexible plastic catheter; both the
needle and the catheter are inserted into the vein, after which the needle is
withdrawn
Which of the following contains points that are enforceable
ARRT Rules of Ethics
Which of the following serves as a guide to professional conduct
ARRT Code of Ethics
According to NCRP Report #160, what is the annual effective dose
equivalent per person from natural background radiation?
3.11 mSv
The x-ray machine
receives what type of current from the incoming line?
120 Hz AC
What is the limit on leakage radiation from a diagnostic x-ray tube?
1 mGya per hour at a distance of 1 m from the housing
The purpose of beam limitation devices is to:
control scatter radiation
The photon-tissue interaction that does not occur in diagnostic imaging is
pair production
Visible light is converted into an electronic image in what part of the imageintensifier tube?
photocathode
mAs controls the number of electrons passing from:
cathode to anode
The WR used to calculate sievert is a measure of what aspect of the radiation being measured?
RBE
Increased dose equals increased
probability of effects?
stochastic
As kVp is increased, the
wavelength of the x-ray photons:
decreases
If ionizing radiation
interacts with a human cell, causing it to die after one or more divisions, it is
classified as:
mitotic death
The blood count is depressed following a whole-body
dose equivalent of at least how many sievert?
0.25
Free
radicals may recombine to form:
hydrogen peroxide
Barium sulfate is a(n):
inert salt
From what anatomic structure does the zygomatic
process arise?
temporal bone
The cardiac portion is where the:
esophagus enters the stomach
Which machine components are located within the gantry?
electron gun
accelerator structure
Which agency is responsible for regulating the manufacturing of linear accelerators?
FDA
Which machine components are located within the drive stand?
klystron
circulator
Which type of breast surgery removes chest wall muscles?
radical mastectomy
What is the typical gantry angle used for supraclavicular fields?
10-15 degrees
Which machine components are located within the treatment head?
target
ion chambers
Which of the following does NOT need to be on a consent form?
treatment dose
Which acute radiation syndrome has the shortest latent stage?
CNS
If MLCs move only when the beam turns off, this is known as:
step and shoot
What is the main difference between VMAT and IMRT?
Gantry & MLCs move during VMAT and only MLCs move during IMRT
What is the last step when donning PPE?
gloves
What is the purpose of the waveguide in a linear accelerator?
accelerate electrons to high energies
Atomic nuclei with differing Z numbers, but the same A number?
isobar
Vaginal cylinders are considered:
HDR
intracavitary
Which type of imaging will cause the MOST compton scatter?
ports
The scattering foil is used to:
spread out electron beam
Which of the following types of radiation can be detected using a Geiger-Muller counter?
gamma
What is the standard fractionation scheme for whole brain radiation therapy?
30 Gy x 10 Fx
Which process helps to generate machine-produced radiation?
electron acceleration
What happens to the energy of a photon as its wavelength decreases?
energy increases
Which of the following radiation units takes into account the biological effects of different types of radiation?
Sv
Which type of radiation is most affected by oxygen enhancement?
xrays
Which of the following is a deterministic effect of radiation exposure?
skin erythema
Which of the following organs is not part of the digestive system?
spleen
Which agency regulates the disposal of radioactive materials in the United States?
NRC
Which of the following parameters in CT simulation is responsible for determining image brightness?
level
Which of the following might be a main risk of using iodinated contrast?
allergic reaction
kidney damage
what does BSF depend on
field size
energy
what is not a symptom of SVC
pain
artery most often used for pulse
radial
artery most accurate for pulse
apical artery
what is used for light field and radiation field checks
monthly
ready pack film and solid water
daily mechanical check
localizing lasers
daily dosimetry check
photon and electron output
1 cm off the CA is a
geometric target miss
is OSL or TLD not affect by heat, moisture or pressure
OSL
use gating when you have more than __ of movement
5 mm
what precaution is used for a virus
standard
cricoid is inf border of
larynx
vertebral body at base of heart
T4
flatness and symmetry check
2%
monthly
ODI check
daily
2 mm
MLC leaf position
1 mm
gantry and coll angle indicators check
monthly
1 degree
asymmetric light field check
1 mm or 1% on a side
monthly
mechanical
symmetric light field
2 mm or 1% on a side
monthly
mechanical
where do celiac and mesenteric lymph nodes meet
cisterna chyli
leak testing for brachy can detect
0.005 micro Ci
is lung adenocarcinoma in periphery or central
periphery
SI unit and original unit for absorbed dose
Gy
rad
SI unit and original unit for dose equivalent
SV
rem
absorbed dose is energy absorbed_____.
in matter
dose equivalent is radiation absorbed______.
by a persone
equation of SV
Gy x QF
what section are personal dosimeters in
dose equivalent
1 R = ________
2.58 x 10^-4 C
energies that are exposure
below 3 MeV
effective dose shows____-
difference of response for organs and tissues
yttrium HL and use
64 hours
liver and lymphoma
gold HL and use
2.7 days
prostate seeds
radon HL
3.8 days
I131 HL and use
8 days
thyroid
phosphorus HL
14 days
palladium HL and use
17 days
prostate implants
low emission
Sr89 HL and use
50 days
bone mets pain
I125 HL and use
59 days
prostate implants
low emission
Ir192 HL and use
74 days
cervix implants in fletcher
nylon ribbon
LDR & HDR
Co60 HL and use
5.27 years
brachy and teletherapy
Sr90 HL and use
29 years
eye (pterygium)
Cs137 HL and use
30 years
brachy for cervix or uterus
cervix implants in fletcher
Ra226 HL and use
1600 years
original radioactive isotope
decays into radon gas
ionic contrast
high osmo
adverse reactions
non ionic contrast
low osmo
fewer adverse reactions
less discomfort
more common
diff between mild and moderate contrast reactions
mild: monitor vitals
moderate: medical intervention
antisdasmodic
GI and IBS symptoms
tumor marker for ovarian cancer
Ca125
analgesic
pain killer
MOPP chemo causes
myelosuppression –> decreased WBC, RBC, platelets
where is the most bone marrow
pelvis
when do you report weight loss to nurse
5% loss in a month
10% loss in 6 months
3 pounds a week
diagnostic radioactive source
technetium - 99 m
1 dps = _____ Ci
2.7 x 10^-11
most common radioisotopes are sealed except for
I131
LDR brachy
40-200 cGy/HR
HDR brachy
0.2 Gy/min - 12 GY/hr
% efficiency for diagnostic xray tubes
1% and 99% converted to heat
energy for coherent
less than 10 KeV
is photoelectric diagnostic or thereapeutic
diagnostic
energy for compton
25 KeV - 10 MeV
energy for photodisintegration
7-15 MeV
difference between elastic and inelastic
elastic: no energy lost
inelastic: some energy lost and reappears (excitation, ionization, brem)
unit that a person absorbs
SV
when do you use lead aprons
fluoroscopic exams
apron shield
0.5 mm lead
2 HVL in diagnostic
reduces exposure to 10%
after how many HLs can radioactive materials be disposed
10
what regulates removal, storage, and usage of nuclear waste
EPA
what regulates safe use of radioactive materials and protects public
NRC
2 examples of ionization chamber
pocket dosimeter
cutie pie
what are correction factors for
if not sealed, for temp, pressure, volume
pocket dosimeter
personal
detect low energy
cutie pie
portable survey meter
what type of radiation dose is monitored using personal dosimeters
equivalent dose
thimble chamber
calibrates ion chambers in LINAC
1) farmer
2) condensor
Geiger Muller
not for personal monitoring
portable
survey rooms
not a dose measuring device
contamination (alpha, beta, gamma)
very sensitive
100 mR and less
TLD
LiF (similar to human)
+/- 5%
excited by heat
solid state detector
OSL
excited by light
AlO
occupational exposure
unique ID
stochastic vs deterministic effects
stochastic: no threshold
- probability and by chance
- ex: carcinogenesis, leukemia, genetic effects
deterministic: threshold
- depends on severity of dose
- ex: cataracts and erythema
chemical used for neutron dosimeter
BF3
machine numbers
40 +/- degrees C
45-50 PSI
SF6 –> 25-32 PSI
diodes
small solid state detectors
real time reading
daily QA for output
not used for calibration
correction factors for CT warmup
760 mmHg
22 degrees C
FOA hazards
class 1: death/serious
class 2: small risk
direct relationship for CT correction factors
pressure and exposure
indirect relationship for CT correction factors
temp and exposure
is OER higher or lower for low LET
higher
higher LET = ____ RBE
higher
what are the most radiosensitive stages of human life
embryo and fetus
stage with prenatal death the most common effect
preimplantation
do early effects have a threshold
yes
acute changes
reduction in parenchymal cells
ex: inflammation, edema, hemorrhage
chronic changes
reduction in stomal and vascular cells
ex: fibrosis, atrophy, ulceration
permanent
GSD for the year
20 mrad/year
radioprotectors
search for free radicals
ex: sulfhydryls and amifostine and ethyol
what does the dose effect factor say
the ratio of radiation dose needed to cause damage without chemo compared to radiation dose needed with chemo
at what point do chemo drugs have a sensitizing effect
DEF is greater than 1
what amplifies microwaves
klystron (above 12 MV)
what generates microwaves
magnetron (low energies)
what stops microwaves from being reflected and going backwards
circulator
between klystron and waveguide
what generates electrons and sends them to the accelerator (waveguide0
electron gun
what is the electron gun made of
tungston
what is the tube that electrons flow to the gantry under a vacuum
accelerator structure
what contains SF6 to prevent arcing
accelerator structure
hyperalimentation
nutrients given via IV for weak and malnourished patients
MUs should be _____ and should not be_____.
should be on the treatment plan
should no be on the prescription
medical event TD
20% difference
medical event one Fx
50% difference
after a medical event, how soon should a written report be submitted
15 days
how soon after a medical event should the patient and physician be informed
within 24 hours
billing charge for patient comfort
no charge
when are devices billed
only once
wh at is a simple tx billed as for sim verification or dry run
simple sim
diff between simple sim, intermediate sim, and complex sim
simple: 1 field and no custom blocking
intermediate: 2 or more tx sites
complex: arc therapy, complex/custom blocking, 3+ tx sites
diff between simple tx, intermediate tx, and complex tx
simple: 1-2 field, 2 simple blocks
intermediate: 2 separate tx areas, 3 fields and 3 simple blocks
complex: 3 tx areas and custom blocks, tangent fiels, wedges, arcs, FIF, electron
weekly port films vs IGRT billing vs IMRT
ports: separate charge
IGRT: billed daily
IMRT: own charge
- simple: breast and prostate
- complex: everything else
main source in our body of internal radioactive elements
potassium 40
picket fence test
radiograph leaves 8 times
each image of MLCs open 5 cm and abut previous field
optical density changes of +/-20% signifies misaligned leaves
IMRT vs non IMRT MLC QA
IMRT: monthly, 1 mm tolerance, speed 0.5 cm/s
non IMRT: monthly, 2 mm tolerance
how often is MLC transmission checked and what is the tolerance
annually
less than 2%
what is the winston lutz test
laser accuracy verification
SRS
islets of langerhans
secrete hormones like insulin and glucagon in pancreas
what organ has local spread in radial style
large bowel
4 lymphatic organs
spleen, thymus, tonsils, thoracic duct
what is reed sternberg cells
giant connective tissue cell that is binucleate
pathology for hodgkins
nodular
classic: lymphocyte rich, nodular sclerosing, mixed cellularity, lymphocyte depleted
most common subcategory for hodgkins
nodular sclerosing
cause of hodgkins vs non hodgkins
hodgkins: EBV
non hodgkins: ionizing radiation
ages of hodgkins vs non hodgkins
hodgkins: 25-30 and 75-80
non hodgkins: older people
signs of hodgkins vs non hodgkins
hodgkins: painless mass
non hodgkins: B symptoms
radiation technique used for hodgkins
mantle
chemo of hodgkins vs non hodgkins
hodgkins: MOPP o/g, ABVD best
non hodkins: CHOP
more common pathology of non hodgkins
diffuse lymphomas
what is the updated version of ann arbor
lugano
oncologic emergencies
SVC
skeletal mets
brain mets w/ increased cranial pressure
vaginal bleeding
how is grade determined
biopsy
nottingham grading system
breast: G1-G3
clinical vs pathological stage
clinical: estimate of extent of tumro
pathological: extent of tumor determined after surgery
ann arbor states
A: no symptoms
B: B symptoms
E: extranodal
S: splenic involvement
breslows vs clark
breslow: tumor invasion of skin layers
clark: microscopic
common tx for 3 field technique
in abdomen
common tx for 4 field technique
deep tumors in pelvis or abdomen
cancers for MRI fused with CT vs PET fused with CT
MRI: prostate
PET: lung, H/N
BSF vs PSF
BSF: low energy
PSF: high energy (+4 MV)
when is DCA used
when 3D without IMRT do not adequately deliver dose to the tumor and spare OAR
what has replaced DCA
VMAT
