(1)
University of Miami Sylvester Cancer Center, Miami, Florida, USA
14.1 Practice Test I: Questions
1.
Radiation protective barriers are designed:
A.
To ensure that the dose equivalent received by any individual does not exceed the applicable maximum permissible value
B.
To ensure that the dose equivalent received by radiation workers only does not exceed the applicable maximum permissible value
C.
To ensure that no one is standing in a controlled or not controlled area
D.
To protect against scatter radiation only
2.
One atomic mass unit is equal to:
A.
1.66 × 10−27 kg
B.
1,862 MeV
C.
1.602 × 10−19 j
D.
0.511 MeV/c2
3.
The total body irradiation (TBI) with megavoltage photon beams is most commonly used in:
A.
Mycosis fungoides
B.
Bone marrow transplantation
C.
The lung
D.
Skin cancer
4.
The energy needed to remove an electron from the shell is called:
A.
The balance electrons
B.
The binding energy
C.
Transitions
D.
Energy levels
5.
What is the dose limit of leakage in locations surrounding the patient’s room (hallway, adjacent patient room, etc.)?
A.
2 mrem/h.
B.
2 rem/h.
C.
10 mrem/h.
D.
The dose rate surrounding the patient’s room is never of concern.
6.
The atoms are designated by atomic symbols; the A symbol represents:
A.
I, II, and III only
B.
I and III only
C.
III and IV only
D.
IV only
E.
All are correct
I.
Atomic number
II.
Number of electrons
III.
Mass number
IV.
Number of protons and neutrons
7.
What is the standard method for the patient to acquire iodine isotopes to treat thyroid cancer?
A.
Injection of solutions with iodine ions.
B.
Swallow iodine salt tabulates with juice.
C.
Implant iodine seeds to thyroid.
D.
Being exposed to radiation of iodine isotopes.
8.
Which of the following is/are true?
A.
I, II, and III only
B.
II and IV only
C.
I and II only
D.
All are true
I.
The activity per unit mass of a radionuclide is termed the half-life.
II.
The number of atoms disintegrating per unit time is proportional to the number of radioactive atoms.
III.
The time required for either the activity or the number of radioactive atoms to decay to half the initial value is termed specific activity.
IV.
The average life or the mean life is the average lifetime for the decay of radioactive atoms.
9.
The x-ray tube consists of:
I.
A cathode
II.
An anode
III.
A glass envelope
IV.
A tissue compensator
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
10.
A nonsurgical, outpatient therapy that uses microscopic radioactive spheres to deliver high dose of radiation directly to the site of the liver tumors is named
A.
Low-dose radiosurgery therapy (LDR)
B.
High-dose radiosurgery therapy (HDR)
C.
Selective internal radiation therapy (SIRT)
D.
Stereotactic radiation therapy (SRT)
11.
Which of the following statements is false?
A.
The anode is made of a tungsten target.
B.
The cathode is a tungsten filament.
C.
Electrons are accelerated toward the cathode.
D.
X-ray emerges through a thin glass beryllium window.
12.
What is the difference between acceptance test and commissioning of equipment?
A.
They are essentially the same.
B.
They are totally irrelevant.
C.
Acceptance test runs a small portion of dataset of commissioning.
D.
Commissioning runs a small portion of dataset of acceptance test.
13.
Which of the following statements about anode target is/are correct?
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The anode target is made of tungsten.
II.
The anode material atomic number (Z) is 74.
III.
The target material must consist of high atomic number and high melting point.
IV.
The target material must consist of high atomic number and low melting point.
14.
The provability of Bremsstrahlung x-ray production fluctuates with:
A.
The 1st power of the atomic number
B.
Atomic mass2 (A 2) of the target material
C.
Atomic number2 (Z 2) of the target material
D.
Voltage applied to the tube
15.
The thickness of an absorber required to attenuate the intensity of the beam to half its original value is a function of:
A.
Energy absorption coefficient
B.
Energy transfer coefficient
C.
Attenuation coefficient
D.
Half-value layer (HVL)
16.
In coherent scattering:
A.
The new photons have the same energy as the incoming photons but are scattered in different directions.
B.
The new photons have the more energy than the incoming photons but are scattered in different directions.
C.
The new photons have the same energy as the incoming photons and are scattered on the same directions.
D.
The new photons have the less energy as the incoming photons but are scattered in different directions.
17.
The probability of a photoelectric interaction depends on:
A.
Atomic number (Z) and energy of the photon (E); the higher the Z of the material, the more likely the interaction, but the higher the energy of the photon, the less likely the interaction.
B.
Atomic number (Z) and energy of the photon (E); the lower the Z of the material, the more likely the interaction, but the higher the energy of the photon, the less likely the interaction.
C.
Atomic number (Z) and energy of the photon (E); the higher the Z of the material, the more likely the interaction, and the lower the energy of the photon, the less likely the interaction.
D.
Atomic number (Z) and energy of the photon (E); the lower the Z of the material, the more likely the interaction, and the lower the energy of the photon, the less likely the interaction.
18.
For pair production to take place, the threshold energy of the incident photon must be:
A.
Equal to 0.51 MeV
B.
Greater than 1.02 MeV
C.
Greater than 2.04 MeV
D.
Less than 1.02 MeV
19.
The greatest limitation in using orthovoltage or deep therapy is:
A.
Skin sparing
B.
Skin surface dose
C.
Cone size
D.
Size and cost of the machine
20.
Treatment parameters (gantry, collimator, field size, dose per fraction, total dose) to be used for a patient’s treatment are controlled by
A.
Ionization chamber (ion chamber is an instrument used in the measurement of the Roentgen according to its definition)
B.
Calorimetry (calorimetry is a basic method of determining absorbed dose in a medium)
C.
Beam handling section (after electrons have been accelerated, they are redirected by the beam handling section which includes the bending magnet, target, scattering foil, or flattening filter)
D.
Record and verify section (the record and verify section controls treatment parameters)
21.
Which of the following parts is/are moved in front of the electron beam when the linear accelerator is in the electron mode?
A.
Scattering foil
B.
Flattening filter
C.
X-ray target
D.
Ion chamber
22.
Ion chambers are made of
A.
High Z materials
B.
Low Z materials
C.
Tungsten
D.
Lead
23.
Spine CyberKnife radiosurgery
A.
Uses external markers (tattoos) for preliminary alignment
B.
Uses implanting fiducials all the time
C.
Uses vest to track spine
D.
Uses mesh for spine tracking
24.
Which of the following is the SI unit of mass?
A.
Second (s)
B.
Ampere (A)
C.
Kilogram (kg)
D.
Meter (m)
25.
Which of the following formula is incorrect?
A.
Velocity (v) = length (l)/time (t)
B.
Acceleration (a) = Velocity (v)/time (t)
C.
Force (F) = mass (m) × acceleration (a)
D.
Power of work (P) = energy (E) × time (t)
26.
The unit, SI unit, and special unit of kerma are
A.
j/kg, Gy, and RAD
B.
j/kg, Gy, and C kg
C.
Gy, Bq, and RAD
D.
j/kg, R, and C kg
27.
Kerma is defined as
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The amount of kinetic energy transferred from photons to charge particles per unit mass
II.
The sum of the initial kinetic energies of all the charged ionizing particles liberated by uncharged particles in a material of mass
III.
The amount of kinetic energy transferred to the electrons
IV.
The quantity of radiation for all types of ionizing radiation
28.
PACS stands for
A.
Picture active computer systems
B.
Printer analog computer systems
C.
Picture archiving and communication systems
D.
Projection access communication systems
29.
The percentage of the absorbed dose at any depth d to the absorbed dose at a fixed reference depth d0 along the central axis of the beam is the definition of:
A.
Mayneord F factor
B.
Percentage depth dose
C.
Tissue-air ratio
D.
Tissue-phantom ratio
30.
The region between the surface and the point of maximum dose is called:
A.
Skin-sparing effect
B.
Dmax
C.
Initial dose buildup region
D.
Penumbra
31.
The equivalent square formula can be used to calculate:
A.
Circular-shaped fields
B.
Irregular-shaped fields
C.
Rectangular-shaped fields
D.
Triangular-shaped fields
32.
A PDD needs to be found for an equivalent square of a rectangular RT tangent breast of 20 cm by 14 cm. Which of the following answers is the equivalent square of the above RT breast tangent field?
A.
23.33
B.
41.11
C.
16.47
D.
4.11
33.
A rectangular field is equivalent to a square field if:
A.
Both have the same area/perimeter (A/P).
B.
Both have different area/perimeter (A/P).
C.
The rectangular is twice as bigger as the square.
D.
Both have the same isocenter.
34.
The increase in PDD with an increase on SSD can be found by:
A.
Mayneord F factor formula
B.
Equivalent square formula
C.
Inverse square formula
D.
Tissue-air ratio formula
35.
155 × 103 is equal to
A.
759,375,000
B.
8,000
C.
75,000
D.
22,781,250
36.
Which the following metric system is equivalent to prefix deka?
A.
10−6
B.
102
C.
10−12
D.
101
37.
What % of 60 Gy is 9?
A.
6.66 %
B.
5.40 %
C.
58 %
D.
15 %
38.
120 rad is equal to how many Gy?
A.
0.1 Gy
B.
1.2 Gy
C.
120 Gy
D.
30 Gy to rad
39.
Radioactivity was first discovered by
A.
Wilhelm Roentgen
B.
Marie Curie
C.
Henri Becquerel
D.
Pierre Curie
40.
Calculate the MU setting for an electron beam RT cheek treatment if the output cutout is 0.972 cGy/MU at Dmax and the physician wants to prescribe a dose of 250 cGy to the 85 % IDL.
A.
206 MU
B.
303 MU
C.
286 MU
D.
257 MU
41.
Calculate the maximum practical range (Rp) of a 12 MeV electron if a tumor is to be treated with a dose of 250 cGy for 30 fractions.
A.
3 cm depth
B.
6 cm depth
C.
8 cm depth
D.
10 cm depth
42.
Calculate the correction to an ionization chamber reading (P t,p) if the treatment room temperature is 21 °C and the pressure is 772 mm mercury.
A.
1.980
B.
0.987
C.
0.980
D.
0.012
43.
Which of the following IGRT systems enables visualization of the exact tumor location by integrating a CT imaging with a linac and involves acquiring multiple planar images?
A.
BAT
B.
Brainlab
C.
Paired orthogonal planar imagers
D.
CBCT
44.
What will be the effect on the chamber reading for a given exposure if the temperature in the room decreases by 10 % and the pressure increase by 10 %?
A.
Approximately 10 % decrease
B.
Approximately 10 % increase
C.
Approximately 5 % increase
D.
Approximately 25 % decrease
45.
Calculate the transmission factor if a lead block measuring 2.5 cm thickness and 10 mm HVL is used to block the esophagus on a patient at 100 SAD.
A.
4 %
B.
0.069 %
C.
2 %
D.
0.062 %
46.
Calculate the wedge factor if the output of a beam is 0.700 without the wedge and 0.350 with the wedge.
A.
2.000
B.
0.500
C.
1.050
D.
0.350
47.
Which of the following treatment devices is used to remove the small bower away from the treatment field?
A.
Alpha cradle
B.
Aquaplast mask
C.
Belly board
D.
Bite block
48.
Calculate the hinge angle used in order to get the most homogeneous dose distribution in a wedged pair technique if 45° wedges are used.
A.
157.5°
B.
67.5°
C.
90°
D.
315°
49.
Calculate the MU setting with a wedge in place if the wedge transmission factor is 0.640 and the MU setting for a field without wedge is 300.
A.
469 MU
B.
192 MU
C.
364 MU
D.
300.6 MU
50.
Tongue and groove is used in MLC to
A.
Reduce interleaf leakages
B.
Correct for lack of divergence
C.
Change the beam into a broad, clinically useful beam
D.
Tilt the isodose lines through a specific angle
51.
What is the dose rate (cGy/ min) a patient received in a cobalt 60 machine if the plan was done using 120 cGy/min at 80 SAD, but the patient was placed at 100 SAD?
A.
96 cGy/ min
B.
76.8 cGy/min
C.
150 cGy/min
D.
100 cGy/min
52.
Calculate the output for a beam that delivers 300 cGy and the monitor unit set is 375.
A.
1.250
B.
0.800
C.
75
D.
80
53.
Rotational therapy is best suited:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
For lateral tumors
II.
For large tumor volumes
III.
For external surface tumors
IV.
For small, deep-seated tumors
54.
Calculate the dose rate if a Co-60 machine delivers 400 cGy in 3 min.
A.
403 cGy/min
B.
0.007 cGy/min
C.
1,200 cGy/min
D.
133 cGy/min
55.
Calculate the MU required to treat a patient whose dose is 180 cGy to the 84 % IDL and the output factor is 0.970 cGy/MU.
A.
156 mu
B.
186 mu
C.
221 mu
D.
147 mu
56.
Calculate the prescribing dose if a dosimetrist evaluates a three-field rectum plan and concludes that the max dose in the plan is 277.5 cGy given to the 111 % IDL.
A.
111 cGy
B.
30.52 cGy
C.
308 cGy
D.
250 cGy
57.
A plan was calculated for 200 cGy daily with an MU setting of 250 to a RT shoulder treatment at 100 SSD using a 20 × 20 field size at a depth of 9 cm, PDD of 78 %, 10 MV, Dmax at 2.5 cm. What would be the new PDD if the physician decided to treat at 115 cm SSD so that part of the ulna is included in the field?
A.
103 %
B.
78.0 %
C.
79.1 %
D.
89.7 %
58.
Calculate the dose received by a patient if the output on a meditational treatment was 0.875 cGy/MU and the calculated MU was 195, but the machine broke and only delivered 105 MU.
A.
91.8 cGy
B.
171 cGy
C.
79.2 cGy
D.
120 cGy
59.
Calculate the off-axis ratio or factor to be used if the tumor lies 10 cm deep and 6 cm lateral from the central axis. PDD at a depth of 10 cm along the central axis is 93.5 %, whereas PDD 6 cm lateral where the tumor lies is 87.3 %.
A.
1.071
B.
0.933
C.
6.200
D.
0.816
60.
Calculate the penumbra width needed in a spine field where the source size is 1.5 cm, and the patient is treated at 100 cm SSD using a source to collimator distance of 75 cm.
A.
3.50 cm
B.
0.50 cm
C.
2.00 cm
D.
1.125 cm
61.
After completing TG-51 measurement, if the result is 3 % off, what should be done next?
A.
Call the vendor to fix the machine.
B.
Nothing, this is within the tolerance.
C.
Adjust the corresponding potential meter to ensure the MU readout becomes correct.
D.
Change the parameters in TPS since the machine output changes.
62.
Calculate a craniospinal field gap if the thoracic spine field measures 38 cm × 8 cm at 100 SSD and the lumbosacral field measures 20 cm × 30 cm at 105 SSD using a depth of 7 cm.
A.
1.99 cm
B.
1.33 cm
C.
0.66 cm
D.
0.67 cm
63.
Calculate the skin gap required if fields A/B are parallel opposed fields having a length of 25 cm and fields C/D are also parallel opposed fields having a length of 15 cm and all fields are treated at midplain, 100 SSD. Patient thickness is 20 cm.
A.
1.25 cm skin gap
B.
2 cm skin gap
C.
0.75 cm skin gap
D.
0.50 cm skin gap
64.
The main interaction responsible for diagnostic imaging is
A.
Coherent scattering
B.
Compton effect
C.
Photoelectric effect
D.
Pair production
65.
What would be the depth needed to calculate the exit dose if a patient is to be planned using a PA spine, max dose of 300 cGy at 2.5 cm depth? Patient thickness is 25 cm.
A.
15 cm depth
B.
12.5 cm depth
C.
22.5 cm depth
D.
25 cm depth
66.
Deterministic effect is defined as:
A.
The probability of occurrence of cancer is higher for higher doses, but the severity of any cancer is independent of dose.
B.
The severity of a particular effect in an exposed individual increases with dose above the threshold for the occurrence of the effect.
C.
The specified dose equivalent an individual is permitted to receive annually from working with radiation on the job.
D.
The probability of occurrence of cancer is the same for any dose received, and late effect is always the case.
67.
From the following table, calculate the total MU setting per fraction if a RT lower leg parallel opposed fields is planned using isocentric technique, patient separation of 12 cm, field size of 12 × 12, and dose to the isocenter of 180 cGy.
Table 14.1
Test 3
Depth | 0 | 1 | 2 | 3 | 4 | 5 | 6 |
PDD | 90 | 95 | 98 | 100 | 80 | 60 | 10 |
Output F | 1.031 cGy/MU at 100 cm SSD, Dmax |
Output F | 1.075 cGy/MU at 100 cm SAD, Dmax |
A.
182 MU
B.
190 MU
C.
231 MU
D.
152 MU
68.
How many cm of lung is equivalent to 1 cm of water or tissue?
A.
5 cm
B.
3 cm
C.
2 cm
D.
10 cm
69.
Calculate the effected path length used to plan a patient’s treatment who has 5 cm of tissue from the skin to the center of the leg where a titanium metal replaces the bone measuring 3 cm, and then from the bone to the back of the femur, there is a separation of 7 cm tissue. Total thickness is 15 cm.
A.
9 cm tissue
B.
15 cm tissue
C.
16.5 cm tissue
D.
20 cm tissue
70.
Radioactivity is defined as
A.
An emission of radiation from unstable nuclei of element in the form of particles, electromagnetic radiation, or both
B.
Radiation in which a particle carries energy capable of removing electrons from an atom producing free radicals
C.
The rate of energy loss per unit path length
D.
The rate of decay of a radioactive material
71.
A plot of the volume of a given structure receiving a certain dose or higher as a function of dose is the definition of
A.
Differential DVH
B.
Cumulative integral DVH
C.
Dose volume histogram (DVH)
D.
Beam’s eye view
72.
A tumor at a depth of 3–4 cm is best treated with
A.
6 MeV
B.
9 MeV
C.
12 MeV
D.
18 MeV
73.
Which of the following is/are correct according to the following DVH graph?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
Fig. 14.1 Test 1 (Courtesy of University of Miami, Sylvester Cancer Center)
I.
Line A, max dose is approximately 9 Gy.
II.
Line B, V20 was achieved.
III.
Line C, 30 % of the volume receives at least 30 Gy.
IV.
Linac D, RX dose of 60 Gy was not achieved.
74.
Which of the following scenarios will not include a DVH?
A.
3-D conformal planning
B.
IMRT planning
C.
IMRT ARC planning
D.
Electron clinical setup
75.
Which of the following statements is/are true?
A.
The dose at any depth is greatest on the central axis of the beam and gradually decreases toward the edges of the beam.
B.
The dose at any depth is lower on the central axis of the beam and gradually increases toward the edges of the beam.
C.
Near the field edges, the dose rate increases rapidly as a function of lateral distance from the beam axis.
D.
Isodose curves at specified depth are not of concern when defining physical penumbra.
76.
If the exposure rate at 3 cm from a source of 137Cs is said to be 3.62 R·cm2/h·mg, what would be the exposure rate at 7 cm from the source?
A.
0.66 R·cm2/h·mg
B.
19.71 R·cm2/h·mg
C.
1.55 R·cm2/h·mg
D.
0.051 R·cm2/h·mg
77.
Horns are
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
High-dose areas near the surface in the periphery of the field
II.
Low-dose areas near the surface in the periphery of the field
III.
Are created by the flattening filter
IV.
Are created by the scatter in the body
78.
Which of the following parameters affect(s) the isodose distribution?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Beam energy
II.
Source size, SSD, and SDD
III.
Collimation
IV.
Field size
79.
Which of the following has the greatest influence in determining the shape of the isodose curves?
A.
Field size
B.
Flattening filter
C.
Source-to-skin distance (SSD)
D.
Beam energy
80.
Which of the following should a medical dosimetrist do?
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Perform radiation treatment planning
II.
Recognize and resolve equipment problems and treatment discrepancies
III.
Recommend when treatment should be withheld until a physician and physicist can be consulted
IV.
Sign radiation prescriptions if the physician and/or physicists are not available
81.
The most commonly used isodose beam-modifying device is
A.
Block
B.
Wedge filter
C.
Cutout
D.
Bolus
82.
A professor asks one of his graduate students to ship a source from one lab to another lab. The student puts the source into the trunk of his car. Is this OK?
A.
Nope. The professor should always ship the source himself.
B.
Yes. It is always fine to use private transportation vehicles.
C.
Only if the student has the proper training on radioactive material handling.
D.
The package should never be handled by a student.
83.
Which of the following is/are correct about wedges?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Tilt the isodose curves toward the thin end.
II.
Tilt the isodose curves toward the thicker end.
III.
The degree of tilt depends on the slope of the wedge filter.
IV.
The degree of tilt depends on the position of the wedge (RT, LT, in or out)
84.
This DVH graph represents
Fig. 14.2 Test 1
A.
Differential DVH graph absolute dose
B.
Cumulative DVH graph absolute dose
C.
Differential DVH graph % dose
D.
Cumulative DVH graph absolute volume
85.
The isodose uniformity distribution depends on
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Patient thickness
II.
Beam energy
III.
Beam flatness
IV.
Correct weighting
86.
What electron energy in MeV should be selected if a tumor is located at 4 cm depth?
A.
6 MeV electron energy
B.
9 MeV electron energy
C.
12 MeV electron energy
D.
16 MeV electron energy
87.
The most clinical useful energy range for electrons is
A.
12–24 MeV
B.
6–12 MeV
C.
6–20 MeV
D.
16–20 MeV
88.
Source-to-skin distance is
A.
SSD = SAD – d
B.
SSD = SAD + d
C.
SSD = SAD/d
D.
SSD = SAD × d
89.
cos30° equals
A.
84.3
B.
0.34
C.
0.87
D.
36
90.
The rate of electron energy loss depends primarily on
A.
Electron density of the medium
B.
Type of cutout used
C.
Electron energy
D.
Type of collision
91.
On Bremsstrahlung interaction, the rate of energy loss on an electron beam per cm is proportional to
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Electron energy
II.
Electron mass
III.
Square of the atomic number (Z 2)
IV.
Rest mass of an electron 0.511
92.
As electron beam energy increases,
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Dose increases.
II.
Surface penumbra decreases.
III.
Penumbra at depth increases.
IV.
Surface penumbra increases.
93.
Which of the following energies generates the highest surface dose or less skin-sparing effect?
A.
6 MeV
B.
9 MeV
C.
12 MeV
D.
16 MeV
94.
Which of the following is/are the result of removing an orbital electron in the K, L, or M shell by a direct hit of an incoming electron?
A.
Photoelectric effect
B.
Characteristic x-rays
C.
Bremsstrahlung x-rays
D.
Compton effect
95.
If the treatment depth on an electron is in doubt, the dosimetrist should:
A.
Use a bigger cutout
B.
Use a bigger cone size
C.
Use higher electron energy
D.
Treatment depth is not important
96.
Uniformity or flatness of the electron beam is usually specified:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
In a plane perpendicular to the beam axis
II.
Horizontal to the beam axis
III.
At the depth of the 95 % isodose beyond the depth of dose maximum
IV.
At Dmax
97.
Advantages of inverse treatment planning IMRT (ITP) over standard forward panning IMRT include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Improved dose homogeneity inside the target volume
II.
Increased speed and lesser complexity of the proposed solution
III.
A quantitative introduction of cost functions, often incorporating dose volume constraints and biological functions
IV.
Adjustment of the optimal treatment planning to the actual dose delivery technique
98.
Which of the following IMRT treatment modes is referred as the sliding window mode?
A.
Segmented MLC mode (SMLC)
B.
Dynamic MLC mode (DMLC)
C.
Intensity-modulated arc therapy (IMAT)
D.
Synchronize MLC mode (SYMLC)
99.
IMRT stands for:
A.
Intensity-multiple radiation therapy
B.
Intensity-modulated rotational therapy
C.
Intensity-modulated radiation therapy
D.
Irregular-modulated radiation therapy
100.
Which of the following statements about magnetron and klystron is/are true?
A.
Both devices produce microwaves.
B.
Both devices can be used in high-energy (>10 MV) linacs.
C.
The magnetron produces microwaves, and the klystron is a microwave amplifier.
D.
Magnetron is more expensive and has a long life span.
101.
IMRT refers to:
A.
Radiation therapy technique in which nonuniform fluence is delivered to the patient from any given position of the treatment beam to optimize the composite dose distribution
B.
Radiation therapy technique in which uniform fluence is delivered to the patient from one to maximum of ten field positions of the treatment beam to optimize the composite dose distribution
C.
Radiation therapy technique in which beams of radiation used in treatment are shaped to match the tumor
D.
Radiation therapy technique in which treatment planning is limited to generating dose distributions in a single or a few planes of the patient’s target volume
102.
What is the purpose of IMRT optimization?
A.
I, II, and III
B.
I and II
C.
I and III
D.
I only
E.
All are correct
I.
To minimize the dose in normal tissue
II.
To maximize the dose in target volume
III.
To generate a dose fluence
IV.
To reduce the treatment time
103.
The prescription for mediastinum lymphoma is 36 Gy, treated in 20 fractionations. The physician decided to treat the patient with AP/PA instead of IMRT. The reason could be:
A.
AP/PA gives fewer doses to normal tissue than IMRT.
B.
To save time, because it might take too long to plan and treat with IMRT.
C.
There is no need to use IMRT because the prescription dose is low.
D.
AP/PA has better outcome for mediastinum lymphoma.
104.
The physician needs an SBRT plan with the target in the abdomen. The patient has been treated before. In this case, is VMAT the better choice over standard IMRT?
A.
Not necessarily, because the main advantage for VMAT is fast delivery of dose.
B.
No. Standard IMRT is better because normal tissue can be avoided by choosing appropriate beam angles by beam’s eye view (BEV).
C.
Yes. VMAT is generally better over standard IMRT in SBRT, because the factional dose of SBRT is huge and VMAT may distribute dose to surrounding normal tissues and reduce the probability normal tissue complication.
D.
Either is a really bad option because the patient was treated before.
105.
Does an IMRT plan use wedges or EDWs?
A.
Yes, to achieve a homogeneous dose, compensators are always needed.
B.
No, an IMRT plan does not care dose homogeneity.
C.
Yes, IMRT has its limitations so wedges are still needed.
D.
No, IMRT can achieve homogeneity with DMLCs.
106.
Which of the following is the mean-life formula?
A.
τ = 1.44 T 1/2
B.
N = N 0e−λτ
C.
A = −λN
D.
T 1/2 = 0.693/λ
107.
What is the normal request for PTV in terms of prescription in an IMRT plan?
A.
100 % of PTV is covered with 100 % of prescription dose.
B.
100 % of PTV is covered with 95 % of prescription dose.
C.
95 % of PTV is covered with 100 % of prescription dose.
D.
95 % of PTV is covered with 95 % of prescription dose.
108.
Which of the following statements is/are true about parallel-opposed beams on TBI treatments?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The higher the beam energy, the greater the dose uniformity for any thickness patient.
II.
The higher the beam energy, the lower the dose uniformity for any thickness patient.
III.
For patients of thickness greater than 35 cm, energies higher than 6 MV should be used to minimize the tissue lateral effect.
IV.
For patients of thickness less than 35 cm, energies higher than 6 MV should be used to minimize the tissue lateral effect.
109.
Which of the following techniques can be used to treat TBI?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Bilateral total body irradiation
II.
AP/PA total body irradiation
III.
Recline AP/PA total body irradiation
IV.
Oblique total body irradiation
110.
Compensator design for TBI is complex because of:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Large variation in body thickness
II.
Lack of complete body immobilization
III.
Internal tissue heterogeneities
IV.
Thickness of compensator
111.
Unlawful physical contact or touching of a person without permission is the definition of:
A.
Assault
B.
False imprisonment
C.
Battery
D.
Invasion of privacy
112.
3√27 is equal to
A.
2
B.
5
C.
10
D.
3
113.
Stereotactic radiosurgery (SRS) is:
A.
A single radiation therapy procedure for treating intracranial lesions
B.
Multiple-dose-fraction procedure for treating intracranial lesions (stereotactic radiotherapy (SRT))
C.
A single radiation therapy procedure for treating lung lesions
D.
Multiple radiation therapy procedure for treating spine lesions
114.
Which of the following devices is used in a stereotactic radiosurgery linac treatment for immobilization?
A.
Stereotactic Aquaplast mask
B.
Stereotactic alpha-credo
C.
Stereotactic frame
D.
Stereotactic bolus
115.
15 cm-long circular cones are used on SRS linac treatments to
A.
Minimize geometric penumbra
B.
Increase the distance (SSD)
C.
Maximize the noncoplanar arcs
D.
Shape the beam’s eye aperture
116.
The maximum channel diameter or field size on a Gamma Knife helmet is
A.
4 mm
B.
8 mm
C.
14 mm
D.
18 mm
117.
When using film for stereotactic radiosurgery (SRS) dosimetry, care must be taken because
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
I.
Films have a size limitation.
II.
Films show energy dependence.
III.
Films show possible directional dependence.
IV.
Films have great statistical uncertainty.
118.
Some of the major components of treatment QA for stereotactic radiosurgery (SRS) include:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Stereotactic frame accuracy
II.
Pedestal or couch mount
III.
Frame alignment with gantry and couch eccentricity
IV.
Congruence of target point with radiation isocenter
119.
Hepatic metastases and primary neoplasms are often
A.
Focal and regular in shape
B.
Focal and irregular in shape
C.
Multifocal and regular in shape
D.
Multifocal and irregular in shape
120.
Which of the following radioisotopes is used on selective internal radiation therapy (SIRT)?
A.
Iridium-192 (Ir-192)
B.
Yttrium-90 (Y-90)
C.
Iodine-125 (I-125)
D.
Phosphrus-32 (P-32)
121.
Which organ would be the major concern for normal tissue complication if the patient is treated with Y-90?
A.
Gallbladder
B.
Lung
C.
Stomach
D.
Pancreas
122.
Which of the following isotope of iodine is used to treat thyroid cancer?
A.
I-123
B.
I-124
C.
I-125
D.
I-131
123.
Which of the following treatments requires an alpha cradle mold for patient immobilization?
A.
Head and neck nasopharynx
B.
Rt Lower leg sarcoma
C.
RT chest wall
D.
Whole brain
124.
Patient’s positioning and device used depend on:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Patient’s medical condition
II.
CT scanning aperture dimension
III.
Location of the disease
IV.
Patient’s preference
125.
Image-guided radiotherapy (IGRT) refers to:
A.
A patient anatomy image technique just before or during delivery of a fraction of radiotherapy to improve accuracy of radiotherapy delivery to the target and avoidance of organs at risk
B.
View of patient from the target, through the beam portal showing patient anatomy within treatment beam
C.
A combined radiation therapy in which a single portal is irradiated both with an electron and a photon beam
D.
An x-ray film taken on the treatment machine with the patient in treatment position and with the beam settings as used for treatment
126.
The nucleus of an atom is composed of
A.
I, II, and III only
B.
I and III only
C.
II and III only
D.
IV only
E.
All are correct
I.
Electrons
II.
Protons
III.
Neutrons
IV.
Positron
127.
The advantage of megavoltage beams for CBCT is:
A.
The beams come from the linac beam line and thus no additional equipment is required to produce the cone beam.
B.
It does produce better soft tissue contrast.
C.
It can rotate a full 360°.
D.
It can produce radiographic and fluoroscopic images.
128.
Name the structure label C
Fig. 14.3 Test 1
129.
IMRT QA involves
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The irradiation of a phantom to verify dose distribution versus dose plan
II.
Verification of hand MU calculations
III.
Verification of treatment safe parameters
IV.
Verification of calculation point not to be close to MLC or in high-dose gradient
130.
Name the structure label D
Fig. 14.4 Test 1
131.
A patient threw away his immobilization mask before being treated to the neck with a boost plan, what would the therapists do? Assume the linear machine is capable of KeV imaging.
A.
Make the patient another mask at linear accelerator couch, and treat with the boost plan.
B.
Redo a CT with a new mask, and ask the dosimetrist to redo the boost plan with the new CT.
C.
Forget about the mask since it was already lost. Ask the dosimetrist to do a simple plan like bilateral or AP/PA for the same dose.
D.
Treat the patient without the mask.
132.
Transient equilibrium is achieved when
A.
The half-life of the daughter is much longer than the half-life of the parent
B.
The half-life of the parent is much longer than the half-life of the daughter
C.
The parent and daughter decay at their own respective half-lives
D.
The half-life of the parent is not much longer than the half-life of the daughter
133.
Adaptive radiotherapy was proposed in recently, which requested a replanning once every 1–3 fractions in hyperfractionation. Will this method help in minimizing the setup uncertainty?
A.
Not really, since it focuses on replanning due to targets changing with time.
B.
Sure, replanning reduces the setup uncertainty because the new plan follows the change of target.
C.
Actually, it depends on whether the target changes with time or not.
D.
It is too early to judge this since it is too new.
134.
Name the structure label F.
Fig. 14.5 Test 1
135.
Which of the following statements is/are true about brachytherapy?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Sources may be left in place for a limited period of time to irradiate the tissues.
II.
Brachytherapy delivers fractionated doses of 120–400 cGy multiple times separated by many hours or days (teletherapy).
III.
Brachytherapy uses sealed sources of ionizing radiation placed within the patient.
IV.
Brachytherapy is an external beam radiation therapy (teletherapy).
136.
The definition of absorbed dose is
A.
Energy loss by electrons per unit path length of a material
B.
Energy absorbed from all ionizing radiations per unit mass of materials
C.
Charge liberated by ionization radiation per unit mass air
D.
Rate at decay of radioactive material per unit time (second)
137.
Exposure rate constant Γ (Rcm2/mCi−h) of 226Ra is
A.
8.25
B.
3.28
C.
10.15
D.
2.38
138.
An opposed AP/PA isocenter abdomen plan is done using 20 × 20 cm field size, 6 MV, patient separation of 40 cm, daily dose of 180 cGy and MU 195, and total number of fractions of 35. The patient is treated to 30 fractions and loses 4 cm due to weight loss. Approximately what will be the new MU correction for the last 5 fractions if separation changed from 40 to 36 cm?
A.
23 MU
B.
171 MU
C.
189 MU
D.
218 MU
139.
The basal dose is defined as
A.
The average of the maximum dose between sources
B.
The average of the minimum dose between sources
C.
The maximum dose in the plane of treatment (state dose)
D.
The total dose contribution from each point
140.
The source used for COMS eye plaque is/are:
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Radium-226 (226Ra)
II.
Iodine-125 (125I)
III.
Gold-198 (198Au)
IV.
Palladium-103 (103Pd)
141.
Which of the following radionuclide(s) is/are actually used for permanent radioactive seed implants?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Palladium-103 (103Pd)
II.
Iridium (192Ir)
III.
Iodine-125 (125I)
IV.
Radium (226Ra)
142.
Which of the following dose volume histograms (DVH) has been found to be more useful and more commonly used?
A.
Differential
B.
Cumulative integral
C.
Isodose curve
D.
Beam’s eye view
143.
Which of the following procedures is/are recommended for intracavitary sources and manual afterloading source identification?
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Source physical length
II.
Source diameter
III.
Source serial number
IV.
Source color coding
144.
Which of the following is the comprehensive AAPM TG Report for permanent prostate seed implant brachytherapy?
A.
TG-43
B.
TG-40
C.
TG-64
D.
TG-128
145.
ALARA stands for:
A.
As low as radiation association
B.
At lower absolute radiation achievable
C.
As low as reasonably achievable
D.
As longer as radiation acquired
146.
HDR pretreatment safety checks must be performed:
A.
Once a week
B.
On any day that the HDR procedure is scheduled
C.
Once a month
D.
Before each patient’s treatment
147.
Calculate the MU required to deliver 250 cGy to the 90 % IDL if the RT breast electron cutout has an output of 1.07 cGy/MU.
A.
260 MU
B.
234 MU
C.
241 MU
D.
268 MU
148.
Which of the following radiation monitoring instruments is best suitable to search for lost clinical radioactive implant sources?
A.
Ionization chambers (Cutie Pie)
B.
Thermoluminescent dosimeters (TLD)
C.
Photographic film
D.
Geiger-Müller counters
149.
Which of the following methods is used to check jaw symmetry?
A.
Graph paper
B.
Pack film
C.
Machinist’s dial indicator
D.
Wiggler point
150.
A Cutie Pie survey meter
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Measures dose rate around an implanted patient and patient room
II.
Surveys in and around the storage area in which radioactive materials are kept
III.
Surveys areas around radiation-producing machines such as 60Co units
IV.
Calibrates linear accelerators or 60Co units
151.
Which of the following is the discipline dealing with what is good or bad, right or wrong, and moral principles that apply values and judgments to the practice of medicine?
A.
Legal concepts
B.
Ethics
C.
Moral ethics
D.
Fidelity
152.
The F factor is:
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
The Roentgen-to-rad conversion factor
II.
Relate dose in air to dose in tissue
III.
Conversion of exposure to absorbed dose
IV.
The rad-to-Roentgen conversion factor
153.
One bit is equal to
A.
A binary digit (0 or 2)
B.
A single digit (1)
C.
A binary digit (0 or 1)
D.
A decimal digit (0–9)
154.
Which of the following technologies is the most rapid in data transportation?
A.
Modem
B.
ISDN
C.
DSL
D.
SS7
155.
The maximum number of electrons that can occupy a specific energy level is determined using the formula:
A.
E klphoton = E k−E l
B.
E = mc 2
C.
2n 2
D.
T 1/2 = Ln2/λ
14.2 Practice Test II: Questions
1.
The advantage(s) of parallel opposed fields is
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct.
I.
Simplicity and reproducibility of setup
II.
Homogeneous dose to the tumor
III.
Less chances of geometrical miss
IV.
Excessive dose to normal tissues and critical organs above and below the tumor
2.
If the temperature is 22 °C and the pressure is 750 mm of mercury, the correction needed to an ionization chamber would be
A.
0.8622
B.
119.79
C.
1.0133
D.
0.0133
3.
Which of the following elements have the same # of neutrons but different # of protons?
A.
Isotopes
B.
Isotones
C.
Isobars
D.
Isomers
4.
What is the difference between acceptance test and commissioning of equipment?
A.
They are essentially the same.
B.
They are totally irrelevant.
C.
Acceptance test runs a small portion of dataset of commissioning.
D.
Commissioning runs a small portion of dataset of acceptance test.
5.
The most stable atoms are
A.
Atoms with even # of protons and odd # of protons
B.
Atoms with odd # of protons and even # of neutrons
C.
Atoms with even # of protons and even # of neutrons
D.
Atoms with odd # of protons and odd # of neutrons
6.
Which of the following is a corresponding characteristic of electron capture?
A.
Z ≥82, same nuclear structure of an 24 He, atomic number (Z) decreases by 2, atomic mass (A) decreases by 4, and particle composed of two protons and two neutrons.
B.
Excessive number of neutrons, high neutron-to-proton (n/p) ratio; reduce n/p ratio by converting a neutron into a proton, negatron, and antineutrino; atomic number (Z) increases by 1, but atomic mass (A) remains the same.
C.
Deficit of neutrons, low neutron-to-proton (n/p) ratio, increase n/p ratio by converting a proton into a neutron and a positron or by capturing an orbital electron; atomic number (Z) decreases by 1, but atomic mass (A) remains the same; consists of a continuous energy distribution.
D.
Deficit of neutrons, low neutron-to-proton (n/p) ratio, increase n/p ratio by capturing one of the orbital electrons by the nucleus transforming a proton into a neutron; often called K capture; gives rise to characteristic x-ray with emission of Auger electrons.
7.
Calculate the projection of field size on a film if on the patient skin measures 20 × 15 and the magnification factor is 1.45.
A.
21.7 × 29
B.
29 × 21.75
C.
21.45 × 16.45
D.
13.8 × 10.34
8.
Intracavitary applicators internal positioning may be examined by
A.
Orthogonal radiographs
B.
Visual inspection
C.
No internal structure exam is required
D.
CT scan
9.
CyberKnife image tracking system
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Images patient at 45° orthogonal angle
II.
Uses two diagnostic x-ray sources plus two ASI image detectors (cameras)
III.
Uses real-time, live images compared against DRRs generated from CT
IV.
The robot adjusts position based on the image/DRR comparison
10.
If an HVL of 2.5 mm tin (Sn) is assigned to a specific machine, what will be approximately the percentage of the radiation beam transmitted through a 15 cm tin (Sn)?
A.
1.56 %
B.
0.89 %
C.
98.44 %
D.
0.015 %
11.
The physicist on your department needs to use I-125 with an activity of 17.8095 mCi on November 10th, but they need to place the order 10 days before (November 1st). What is the activity of I-125 at the time of shipping (November 1st)?
A.
20 mCi
B.
0.0116 mCi
C.
59.6 mCi
D.
25 mCi
12.
If penetration power of the beam is needed:
A.
Added filtration and/or decreased voltage across the tube can be used.
B.
Added filtration and/or increase voltage across the tube can be used.
C.
Inherent filtration and/or decreased KVP across the tube can be used.
D.
Inherent filtration and/or increase MAS can be used.
13.
If a Compton photon interacts with an orbital electron by direct hit,
A.
No energy is transferred.
B.
Electron will receive maximum energy, and scatter photon will leave with minimum energy.
C.
Photon with energy of 0.511 MeV.
D.
Incoming photon with energy up to 50 KeV.
14.
The basal dose is defined as
A.
The average of the maximum dose between sources
B.
The average of the minimum dose between sources
C.
The maximum dose in the plane of treatment (state dose)
D.
The total dose contribution from each point
15.
Which of the following is/are indirect ionization?
A.
X- rays
B.
γ-rays
C.
Neutrons
D.
All are correct.
16.
The lateral distance between two specified isodose curves at specified depth is used to estimate
A.
Tissue lateral effect
B.
Transmission penumbra
C.
Physical penumbra
D.
Beam profiled
17.
Closed-circuit television and audio monitoring systems
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Are required in treatment rooms
II.
Should be checked daily for proper operation
III.
Should be turned on for all treatments
IV.
Are not necessary if any tracking system (calypso, respiratory gating, etc.) is used
18.
CyberKnife path is defined as
A.
Preassigned points in space where the linac can deliver radiation from multiple beam angels
B.
Preassigned points in space where the manipulator is allowed to stop in order to deliver radiation dose
C.
A fixed and predetermined workspace where the robotic arm can move
D.
The geometric isocenter where the beam is aimed
19.
1 mg-Ra eq is equal to
A.
8.25 × 10−4mR/h at 1 m
B.
8.25 × 10−4R/h at 1 m
C.
8.25 × 10−2R/h at 1 m
D.
8.25 × 10R/h at 1 m
20.
The point of intersection of the collimator axis and the axis of rotation of the gantry is known as:
A.
Secondary collimator
B.
SSD
C.
Wiggler point
D.
Isocenter
21.
A source is considered to be leaking if a presence of
A.
0.5 μCi or more of removable contamination is measured
B.
0.05 μCi or more of removable contamination is measured
C.
0.005 μCi or more of removable contamination is measured
D.
0.0005 μCi or more of removable contamination is measured
22.
The most frequently used TLD material for clinical dosimetry is
A.
Lithium borate (Li2B407)
B.
Calcium fluoride (CaF2:Mn and nat)
C.
Calcium sulfate (CaSo4:Mn)
D.
Lithium fluoride (LIF)
23.
The 90 % depth dose of a 16 MeV occurs at
A.
2 cm
B.
4 cm
C.
5 cm
D.
8 cm
24.
Radiochromic films’ response depends on
A.
Humidity
B.
Pressure
C.
Temperature
D.
Chemical processing
25.
Outside the geometric limits of the beam and the penumbra, the dose variation is the result of
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Side scatter from the field
II.
Lateral scatter from the medium
III.
Leakage and scatter from the collimator
IV.
Leakage from the head of the machine
26.
What is the difference between 3D-CRT hyperfractionation strategy and IMRT hyperfractionation strategy?
A.
Both are efforts to minimize normal tissue complications, and IMRT does a better job.
B.
Both are efforts to enhance better treatment outcomes, and IMRT does a better job.
C.
IMRT does a better job in both minimizing normal tissue complications and treatment outcomes.
D.
Both are efforts to enhance treatment outcomes and to minimize normal tissue complications and IMRT does a better job in both of them.
27.
Determine the treatment time to deliver 150 cGy (rad) at the center of rotation of an arc treatment where the dose rate in free space at SAD is 80.5 cGy/min and the average TAR is 0.550.
A.
3 min
B.
3.39 cGy/min
C.
3.39 min
D.
5 min
28.
Field shaping can be accomplished in electron beam therapy by using
A.
MLC
B.
Cones
C.
Cutout
D.
Wedges
29.
SAR depends on:
A.
I, II, and III only
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Beam energy
II.
Depth
III.
Field size
IV.
SSD
30.
Which of the following diseases is/are primarily treated with radiosurgery CyberKnife treatment?
A.
I, II, and III
B.
I and III only
C.
II and IV only
D.
IV only
E.
All are correct
I.
Meningiomas
II.
Acoustic neuroma
III.
Gliomas
IV.
Trigeminal nerve
31.
The rate of kinetic energy loss per unit path length of charged particle is
A.
Mass stopping power
B.
Stopping power
C.
LET
D.
Activity
32.
For Gamma Knife, CyberKnife, standard IMRT, and VMAT, if all normalized to body maximum, which one of following is correct for reasonable isodose lines to be chosen?
A.
60 %, 70 %, 95 %, 90 %
B.
50 %, 70 %, 95 %, 90 %
C.
60 %, 70 %, 98 %, 90 %
D.
50 %, 60 %, 95 %, 90 %
E.
50 %, 70 %, 95 %, 90 %
33.
Which of the following corresponds to the diagram?
A.
TMR
B.
PDD
C.
SAR
D.
BSF
Fig. 14.6 Test 2
34.
How could therapy with Y-90 selectively treat hepatocellular carcinoma (hcc) alone in the liver without putting a lot of dose to the most healthy part of the liver?
A.
Hepatocellular carcinoma selectively absorbs Y-90 solution.
B.
There uptakes of Y-90 in other parts of the liver are negligible although blood flowing through carries Y-90.
C.
Blood which flows carrying Y-90 mainly passes through the part of the organ which has a disease.
D.
Tumor is more sensitive to radiation than healthy normal tissues in the organ.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
