Mosby 2 Flashcards
the HDR brachytherapy room should have a zone monitor to
indicate any potential exposure
the patient experiencing dry desquamation should be advised to
apply radiation dermatitis ointments no sooner than 1 hour before treatment
if the threshold energy of 1.022 MeV is not present for beta+ decay to occur, then a nucleus with an excess number of protons will release energy by
electron capture
brachial plexopathy is a possible adverse effect following high dose irradiation to the
supraclavicular fossa
the radionuclide Tc-99m is an example of an
isomer
what is the approximate location of the external iliac lymph nodes?
1 cm lateral of the pelvic rim
which portion does not provide protection for the brain?
cerebellum- in the posterior portion of the brain
earlier generation therapy machines called orthovoltage machines operated in the range of
150 to 500 kV
when radiation passes through matter, is may produce positively and negatively charged particles known as
ions
for a clinical whole brain without the use of a face mask, the inferior border will be at the mastoid process and
supraorbital ridge, external auditory meatus
when treating the maxillary antrum the organ at the greatest risk for damage is the
lens
the traditional unit of absorbed dose equivalent is the
REM
0.01 joule/kg is equivalent to
1 RAD
what thickness of cerrobend would be equivalent to 8 cm of lead
9.6 cm of cerrobend
which of the following therapeutic ratios would be expected to provide the highest probability of cure
1.75
a representation of the dose in an irradiated volume, as a function of spatial position along a single line is known as a/an
dose profile
the factors to consider for the thickness of protective barriers include distance, occupancy, and
workload and use
compared to xrays the LET for protons is
higher
how many lobes does the left lung have?
2
how many lobes does the right lung have?
3
the prodromal stage of acute radiation syndrome consists of
nausea
within the first two weeks of standard, fractionated radiation therapy the patient will experience
erythema, and epilation
the main route of breast carcinoma as it metastasizes is first through the
axillary lymph
when using film for portal imaging, the size of the enlarged image or shadow on the film is dependent on
target to object distance, target to film distance
what is normal platelet count ranges?
150,000 to 450,000
if the electron energy selected is 12 MeV, this energy selected indicates the
maximum energy of electrons in the beam
contact with secretions transferred by sneezing, coughing, or talking is an example of which kind of means of transmission
droplet
the classification of a neoplasm is based on
pathology, biologic behavior, anatomic site, degree of differentiation
the spinal cord proper in the adult extends from the
foramen magnum to the second lumbar spine
one type of natural background radiation is
cosmic and terrestrial
if distance is doubled, the intensity of radiation will be
reduced by a factor of four
what is the tunica albuginea in the ovary?
capsule of collagenous connective tissue
the skin dose in the case of electron beams is about
80-90%
what will create a streaking artifact on a CT image
dense metals, titanium hip prosthesis, metallic dental fillings
patients should be weighed and remeasured through the treatment axis periodically so that
anatomic variations can be monitored
a stochastic effect is best defined as one in which
probability of a latent effect is dose dependent
what would influence the onset or duration of action for a certain drug?
nutrition
your patient has a continuous infusion chemotherapy regulator. during treatment, the regulator apparatus begins to alarm. you should:
alert a physician or nurse
which tumor marker among the following is helpful in the diagnosis of testicular cancer
alpha fetoprotein
the dose rate for low dose rate brachytherapy procedures is typically
2 Gy/ Minute
the early effects of radiation occur
within a few weeks of exposure
the average energy deposited per unit path length to a medium by ionizing radiation as it passes through that medium best describes
linear energy transfer
what is an example of imaging modalities that is not functional imaging?
CT
a lumbar spine field with the central axis at lumbar vertebrae number 3 will be located at about the level of the ___ on the patients skin surface
iliac crest
biological effects are more prominent with
heavily ionizing radiation and high LET radiation
weakened proximal pelvic muscles, impotence, and bladder paralysis may be signs of a spinal tumor located in what region
lumbosacral
exposure is measured in
coulombs per kilogram (C/kg)
the ___ plane divides the body into right and left segments.
sagittal
which of the following is defined as Planck’s constant?
6.62 x 10 ^34 J-sec
external beam radiation for cancers of the mid esophagus is best delivered using
anterior and two posterior obliques
hair loss is usually permanent when the scalp is exposed to radiation doses exceeding
60 Gy
the target volume includes the regional nodes. the caudal margin is the inferior border of the obturator foramen. the cephalic margin is L5. the lateral margins are 1 cm beyond the true pelvis. the nodes included are the external and internal iliac. the target volume is:
bladder
the volume of lung within an anterior supraclavicular field can be reduced when treating breast carcinoma by
moving the breast down on the chest wall and making the match line as superior as possible
the radiosensitivity of a tumor could depend upon the
mitotic rate, tumor growth fraction, histology
the cancer management modality most likely to induce remission in newly diagnosed leukemia
chemotherapy
in order to make custom cerrobend blocks, the following information is needed
target to film distance and beam energy
the photoelectric process is essentially an interaction between a photon and
a bound electron
mucositis is more likely to occur in which of the following malignant conditions
leukemia
the normal limits for BUN in mg/dL for the adult are
10-20
the anterior margin is based extension into the nasal cavity. the superior border is at the base of the skull. the posterior margin includes the posterior cervical nodes. the caudal margin is at the inferior aspect of the clavicle. the target volume just described is for treatment of
nasopharynx
what is the CT number of water on a Hounsfield scale?
0
the clinical target volume includes
gross target and subclinical disease
a patient who is in cardiac arrest is a level ___ on the Karnofsky scale
0
bite blocks may be used in head and neck photon irradiation to
protect the oral cavity from the primary beam
which part of the larynx contains the true vocal cords
glottis
if heavy charged particles have a quality factor of 20, what is the absorbed dose equivalent for 100 cGy
20 Sv
when a missing tissue compensator is used, it should be placed
at some distance from the skin surface
about one week after the infusion of certain chemotherapy agents, the skin in a previously irradiated area may show signs of erythema, blistering, and pain. this phenomenon is known as radiation
recall
patients should be warned to avoid ___ because it repels, rather than attracts moisture to the skin
petroleum jelly
the system international’s unit for activity is the
becquerel
percent depth dose varies with
depth, field size, radiation quality
to prevent the distant spread of prostatic tumors, the ___ should be included in the treatment fields
common iliac nodes
the radiation unit for absorbed dose equivalent is the ___ while the SI unit is the sievert
rem
the half-life of cobalt 60 is
5.26 years
the common area of spread for medulloblastoma is
cerebrospinal fluids
how much energy is in one atomic mass unit
931 MeV
