Failed Mosby Questions Flashcards
1
Q
The primary function of area control activities, personnel monitoring, and proper radioactive material disposal is for the:
A
determination of appropriate ALARA procedures and process
2
Q
It is recommended that therapists working on high energy accelerators limit the time used handling physical wedges and custom blocks to protect hands from:
A
Neutron contamination
3
Q
What thickness of cerrobend would be equivalent to 8 cm of lead?
A
9.6
Cerrobend is about 15% less dense than lead. To figure the equivalent attenuation of cerrobend to lead, use the factor 1.2. 1 cm lead = 1.2 cm cerrobend.
4
Q
Cerrobend is ____ less dense than lead
1 cm lead = ___ cm cerrobend
A
15%
1.5 cm
5
Q
Which of the following therapeutic ratios would be expected to provide the highest probability of cure?
A. 0.85
B. 1
C. 1.45
D. 1.75
A
1.75 -
The highest probability of cure is expected with the highest therapeutic ratio. Normal tissue tolerance/tumor lethal dose = therapeutic ratio.
6
Q
The most appropriate position for examination of the perineal area is:
A
Lithotomy
Lithotomy position has the patient supine with both legs elevated and with knees toward the chest. This position is appropriate for examination of the perineal area.
7
Q
On inspiration, the diaphragm moves:
A
Caudad (toward feet)
8
Q
On inspiration, the diaphragm moves:
A
Caudad
9
Q
The ability to displace the small bowel away from pelvic fields depends on:
A
whether the patient has had previous pelvic surgery
body habitus
patient mobility
10
Q
Patients undergoing irradiation for breast cancer can be positioned:
A
supine, prone, or lateral oblique
11
Q
When radiation passes through matter, it may produce positively and negatively charged particles known as:
A
ions
12
Q
A device used to measure patient diameter and body thickness is called a:
A
caliper
13
Q
A dosimeter consisting of ferrous sulfate, sodium chloride, and sulfuric acid is called a/an:
A
Fricke dosimeter
The Fricke dosimeter contains ferrous sulfate, sodium chloride, and sulfuric acid. The monitoring process relies on chemical reaction following exposure.
14
Q
The annual dose limit for members of the general public is:
A
0.1 rem/1 mSv
15
Q
As SSD increases, depth dose:
A
increases
16
Q
Treatment should be withheld if:
1. patient refuses
2. unexpected side effects are reported
3. WBC is 4500
A
1, 2.
No treatment should be given if the patient refuses or reports unexpected side effects.
WBC counts are normal
17
Q
The term used to define the area on the surface of the patient on which radiation is incident is the:
A
entrance point
18
Q
A patient is to be given 300 cGy using a Lucite blocking tray. If the tray factor is 0.970 was not included in the dose calculation, what was the actual dose delivered?
A
291
The block has been attenuating some of the dose. To find the actual dose delivered, multiply the factor by the intended dose. 300(0.97) = 291.
19
Q
As the overall time of treatment is altered, with fraction size and total dose remaining unchanged, the biological effect:
A
increases as time is shortened
20
Q
While treating early to midstage vulvar cancer, the patient may be positioned in the frog-legged position in order to avoid:
A
increased dose in the inguinal fold
21
Q
Which of the following is the energy of a photon detected by Positron Emission Tomography (PET)?
A
511 kV
22
Q
How many atoms are in one gram atomic weight of I-125?
A
4.81 x 1021 atoms
The number of atoms in one gram atomic weight is given by Avogadro’s number (6.0228 x 1023). Dividing this number by the gram atomic weight of any element will give the number of atoms per gram atomic weight.
23
Q
If a 50 keV electron collides with an inner shell electron with a binding energy of 25 keV, the resulting photoelectron will have an energy of:
A
25 keV
24
Q
The linear attenuation coefficient (μ) is expressed in:
A
1/cm
photons attenuated per unit mass
25
Is independent of density
The mass attenuation coefficient (μ/ρ):
26
If half-value layer is defined by 0.693/μ or (ln2/u), then tenth-value layer is defined by:
ln10/u
27
Which of the following best describes an isodose curve?
Points within the patient receiving the same dose are joined together forming a curve.
28
Which of the following parameters is Tissue Maximum Ratio (TMR) not dependent upon?
SSD
29
In radiation therapy, which of the following interactions with matter are least important?
photoelectric effect
30
1500 photons from a photon beam are directed toward a metal block that is 10 cm thick. 375 photons emerge from the other side of the block. What is the half-value layer of this metal block?
5 cm
Half-value layer (HVL) is the thickness that will reduce a photon beam to half of its original intensity. 375 photons are 25% of the original number of photons so the block is two half-value layers thick. The block is 10 cm thick so the HVL of the block is 5 cm. This problem can also be solved by the exponential equation.
31
Which of the following best defines a wedge factor?
ratio of dose at depth with the wedge inserted to the dose at depth with no wedge inserted
- dose w wedge : dose no wedge
32
In Relative Biologic Effectiveness (RBE), the biologic effect of a particular type of radiation for a given dose is compared to the biologic effects of _________ for the same dose.
250 kV x-rays
33
A 30-year-old radiation worker would be allowed _______rem whole-body cumulative exposure.
30
NCRP recommendations for lifetime exposure can be figured by 10 mSv x age in years.
34
Why is Ir-192 the commonly used source in High Dose Rate (HDR) afterloading brachytherapy?
It has a high specific activity and lower photon energy.
35
The external testicular shield used when treating seminoma is intended to protect the remaining testicle from:
The external shield protects the remaining testicle from internal scatter near the perineum.
36
A dizzy feeling associated with sitting or standing after a prolonged period of bed rest is called:
postural hypotension
37
The energy of an electromagnetic radiation is inversely proportional to its:
wavelength
See the electromagnetic spectrum. The energy is inversely proportional to the wavelength.
38
If you are helping a patient who has suffered a stroke, you should position yourself:
on the patient's weak side
39
Which of the following would be important to consider in the initial workup for a diagnosis of CNS malignancy?
A. family history
B. environmental exposures
C. changes in behavior or personality
D. all of the above
D. all of the above
40
Regarding management of skin reactions, all of the following are true except:
A. Erythematous areas should be kept moist.
B. Prevention of further injury is best.
C. Corn starch may bring some relief.
D. Heat and sunlight should be avoided.
A.
Skin should be kept clean and dry
41
A tumor lethal dose is 5000 cGy. The spinal cord is adjacent to the tumor. The approximate therapeutic ratio is:
Therapeutic ratio is normal tissue tolerance/tumor lethal dose. Without considering the volume of cord irradiated, the accepted tolerance is 45 Gy. 45/50 = 0.9.
42
During verification placement imaging for radioactive needles, the image receptor is located 120 cm from the source. The 3-inch needles measure 4.0 cm on the film. How far away were the needles from the image receptor?
30 cm
Find mag factor, subtract 90 from 120
mag factor: size1/SSD1 = size2/SSD2
43
What thickness of cerrobend would be equivalent to 5 cm of lead?
A. 4.2
B. 5
C. 6
D. 7.2
C. 6
Cerrobend is about 15% less dense than lead. To figure the equivalent attenuation of cerrobend to lead, use the factor 1.2. 1 cm lead = 1.2 cm cerrobend.
44
In order to reduce the potential for electron contamination, the preferred material for custom block and compensator holders is:
Lucite
45
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
46
The equivalent square field size must be determined in order to calculate the:
dose to be delivered to the central axis of an irregular (nonsquare) field
47
The tolerance for variation in collimator rotation around the point of isocenter is:
2 mm
48
Which of the following cancers is most likely to spread through lymphatics?
A. choriocarcinoma
B. seminoma
C. medulloblastoma
D. osteogenic sarcoma
B. seminoma
49
Luteinizing hormone (LH) is secreted by the _____ gland
Pituitary
50
For total skin irradiation:
A. The patient should be sedated.
B. The patient should move in the beam.
C. The patient should be wet for bolus effect.
D. Boost fields may be necessary for areas not included in the fields.
D. boost fields may be necessary
51
In order to evaluate the blood pressure a___________is required.
sphygmomanometer
52
The tolerance dose (TD 5/5) for the optic chiasm is:
60 Gy
53
In which region of the pharynx are the palatine tonsils located?
oropharynx
The palatine or faucial tonsils as well as the lingual tonsils are located in the oropharynx.
54
Processed meat is associated with _____ cancer
Distal colon cancer
55
The lymphatics included in radiation treatment fields for a glioblastoma multiforme in the right temporal lobe would include:
A. retropharyngeal
B. preauricular
C. parotid
D. none of the above
D. none of the above
There is no lymphatic drainage in the central nervous system. No lymph nodes are included in radiation fields for tumors of the brain.
56
Hodgkin's disease is most common in:
males and females younger than 35 years old
Hodgkin's disease has two peaks of incidence. One peak is adolescence through early adulthood, and the other peak is over 60 years old.
57
A dose of 300 cGy was to be delivered to the thoracic spine at 95 cm SSD. An error caused treatment to be given at an SSD of 92 cm. The actual dose delivered was:
320 cGy
I1/I2 = D2/D1^2
58
The French-American-British (FAB) staging system is used to classify:
acute leukemia
The FAB staging system is used to classify acute leukemia using three levels for cell size in ALL or seven levels for maturation of cells in AML.
59
The uterus includes which of the following anatomical areas?
1. eustachian tubes
2. fallopian tubes
3. fundus
4. cervix
3, 4
60
Between the thyroid notch and cricoid cartilage lies the:
larynx
61
The xiphoid process is about at the level of:
T10
62
important to detect early stage cancers because smaller tumors show:
less cells, easier to kill
63
Which of the following has the highest LET?
A. photons
B. electrons
C. alpha particles
D. microwaves
C. Alpha particles
64
The shape of the isodose curves depends largely upon:
1. field size
2. depth dose
3. flattening filters
4. SSD
B. 1, 3
65
The width of penumbra increases with increasing:
SSD
Penumbra increases with increasing SSD and source size.
66
Which of the following is not required for giving consent?
A. legal age and mental competency
B. acknowledgment of risks
C. understanding of procedure
D. medical background and credentials
D. medical background and credentials
67
Custom shielding blocks that are divergent reduce:
beam edge cutoff
68
Your patient is suspected to have a perforated bowel. Which contrast agent is best to use for visualization of the bowel on conventional X-ray?
oral iodine based contrast
69
Which of the following has the highest frequency?
A. X-rays
B. visible light
C. microwaves
D. radio waves
A. x-rays
Refer to the electromagnetic spectrum. Frequency is proportional to energy. X-rays and gamma rays are at the end of the spectrum and have higher energy and frequency than the other radiation types listed.
70
Umbilical region
midabdomen
71
Dose with deepest dmax will have the best skin sparing effect
true
72
Which of the following is the definition of linear attenuation coefficient (μ)?
fraction of photons attenuated per unit thickness
73
In a craniospinal treatment technique, the beam divergence from the lateral brain fields and the posterior spine field must be matched to avoid dose overlap. This is achieved by:
A. rotating the collimator of the lateral brain fields so the inferior border matches the superior divergence of the posterior spine field
B. angling the treatment couch toward the collimator so that the inferior divergence of the lateral brain fields matches the superior divergence of the posterior spine field
C. using a half-beam block on the lateral brain fields to match the superior divergence of the posterior spine field
D. a and b
D. a and b
Correct matching of the beam divergence of the lateral brain fields and the posterior spine field involve rotating the collimator of the lateral fields and angling the treatment couch towards the collimator.
74
The TD 5/5 for the lens of the eye is:
The tolerance for the lens of the eye is 500 to 1000 cGy.
75
The normal limits for PSA in the patient under 60 years old is less than or equal to:
4 ng/mL
76
Light field and radiation field congruence should be checked:
monthly
77
The physical field size is defined at the:
50% isodose line
78
Leak tests of sealed radioactive sources should be conducted at________intervals.
6 month
79
A high-energy photon strikes an orbital electron and scatters exactly 180 degrees. What is the maximum energy of the scattered photon?
255 kV
From the law of conservation of energy and momentum, it can be shown that an incident photon with a very high energy directly striking an electron and being scattered 180 degrees will have a maximum energy of 255 kV. The majority of the incident photon energy will be imparted to the electron.
80
The photons produced during the orbital transitions of electrons from a higher to lower energy shell are called:
characteristic radiation
81
The layers of the alimentary canal from innermost to outermost are the:
mucosa, submucosa, muscularis, serosa
82
The anterior margin flashes over the anterior surface of the neck. The posterior margin includes the arytenoids. The superior margin includes the infra-hyoid epiglottis and the inferior margin includes the cricoid cartilage. This describes the target volume for the treatment of the:
true vocal cord
The true vocal cords, glottic larynx in early stage, is treated with small fields that flash over the anterior surface of the neck.
83
Increasing the mA when performing a CT scan will:
increase the number of photons in the X-ray beam
increase the current to the tube
84
The parathyroids are located on the:
posterior surface of both thyroid lobes
85
The radionuclide Tc-99m is an example of an:
isoMER
Tc-99m has the same number of protons and neutrons as Tc-99 but is in a metastable nuclear energy state.
86
half life of I-125 is:
60.2 days
87
What percentage of adenomatous polyps of the colon contains invasive cancer cells?
3%-5%
88
All naturally occurring radioactive series ultimately decay to a stable form of:
lead
89
The definitive treatment modality for the treatment of colon cancer is:
surgical resection
90
Which of the following techniques is used to treat early pre-cancers of the cervix?
loop electrosurgical excision
The LEEP, loop electrosurgical excision procedure, is a suitable technique used to remove precancerous tissue from the cervix.
91
Epistaxis is another name for:
nosebleed
92
Which artery is most often used to take the pulse in the ambulatory adult?
radial
93
Malignant neoplasms that originate in lympho-reticular tissues are called:
lymphomas
94
General signs and symptoms of shock include all of the following except:
A. weak, thready pulse
B. rapid heartbeat
C. increased temperature
D. hypotension
C. increased temperature
95
In which of the following diseases is it important to include regional lymphatics?
A. T1 glottic larynx carcinoma
B. glioblastoma multiforme
C. nasopharynx carcinoma
D. osteosarcoma of the femur
c. nasopharynx carcinoma
All of the mentioned malignancies do not spread through regional lymphatics, with the exception of malignancies of the nasopharynx.
96
Why is a stereotactic frame used in linear accelerator based stereotactic radiosurgery?
to provide reference for identifying the target
97
The time after exposure to radiation before the long-term effects become apparent is called the______period.
latent
98
For a clinical whole brain without the use of a face mask, the inferior border will be at the mastoid process and (select two):
1. lateral canthus
2. supraorbital ridge
3. external auditory meatus
4. lower ear attachment
2.SOM
3. EAM
99
A Fletcher-Suite applicator consists of a:
tandem and a pair of ovoids.
100
pituitary gland is located in the:
sella turcica
101
Prophylactic cranial irradiation for ALL is administered to a total dose of:
1800 cGy
102
FDG-PET imaging may be able to detect tumors not demonstrated on CT due to:
higher glucose metabolic rates of malignant cells
103
Which of the following photon interactions with matter involves energy being converted to mass?
pair production
The photon interacts with the atomic nucleus resulting in the production of an electron and a positron. The energy of the photon was converted in the mass of the electron and positron.
104
Which of the following examination instruments is necessary for examination of the pharynx?
laryngeal mirror
105
A patient who is in cardiac arrest is a level_______on the Karnofsky performance scale.
0
106
Shielding design and materials should reduce patient, personnel, and public exposure to:
A. primary radiation
B. secondary radiation
C. background radiation
D. a and b
D. a and b
(ie, gets rid of background radiation)
107
The usual position for breast treatment includes elevation of the arm on the affected side. The angle of elevation should principally depend on the patient's ability to:
A. elevate the arm and the angle of the medial tangent
B. move through the CT simulator bore
C. elevate the arm and evaluate how the skin folds upon elevating
D. elevate the arm and keep the chest slope under 20 degrees
C. elevate arm and evaluate how skin folds
108
Which of the following equipment produces extra nuclear indirectly ionizing radiation?
A. Cobalt-60 unit
B. linear accelerator
C. Ir-192 high-dose-rate afterloader
D. none of the above
B. linacc
Photons are produced by a linear accelerator through the bremsstrahlung interaction that occurs when electrons impinge on a target.
109
Which of the following radioisotopes is sometimes administered into the peritoneal cavity in the treatment of gynecological malignancies?
Phosphorus-32
110
Which of the following photon beam energies would have the highest HVL for the same absorber material?
6 MV
Higher beam energies are more penetrating and require more absorber material to reduce the beam to half of its original intensity.
111
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
An electron is captured by the nucleus, and a proton is converted to a neutron.
112
Which theory of radiation interaction is illustrated by the operating principles of an ionization chamber?
Bragg-Gray theory
Bragg-Gray cavity theory states that ionization in an air cavity can be related to ionization in a medium.
113
When treating adjacent, multiple fields on a patient:
Patient position should remain the same for all fields.
114
The cancer management modality most likely to induce remission in newly diagnosed leukemia is:
chemotherapy
115
When the primary beam penetrates an object, much of it is scattered in all directions. This is known as:
secondary radiation
116
Earlier generation therapy machines called orthovoltage machines operated in the range of:
150-500 kV
117
Which imaging technique could show the shape, texture, and composition of cysts and tumors as well as flow in fluid-filled structures?
Ultrasound
118
0.01 joule/kg is equivalent to:
1 rad
1 gGray = 1 joule/kg. Therefore 1 rad = .01 gGray = .01 joule/kg.
119
Fine needle aspiration can be used for bone biopsy. What is the main disadvantage of this procedure?
The histological architecture of the bone might not be preserved.
120
The diagnosis with the best chance for cure among the following would be:
A. non-Hodgkin's lymphoma
B. adenocarcinoma of the stomach
C. bronchogenic carcinoma
D. basal cell carcinoma
D. basal cell carcinoma
121
Which is not true of the electromagnetic spectrum? All photons in the spectrum have the same:
energy
122
photons do not have:
velocity, mass, charge
123
Which one of the following is not characteristic of cancer?
A. blood vessel invasion
B. high mitotic activity
C. encapsulation
D. undifferentiation
D. undifferentiation
Malignant tumors are not encapsulated. This gives them the freedom to invade neighboring tissues, invade blood vessels and lymph, and metastasize to distant organs.
124
Which of the following disorders is the likely cause of reported familial clusters of esophageal squamous cell cancers?
tylosis
Tylosis is a rare genetic disorder that is associated with squamous cell esophagus cancers seen in familial clusters.
125
The depth of the 80% dose line for a clinical electron beam energy is given by:
1/3
The depth of the 80% dose line is found by dividing the energy by 3.
126
The wavelengths of X-rays are measured in
angstroms
