Medical
Physics(Ph.D.)
1.
A body at high temperature T °K radiates heat at
rate proportional to
A)
T4
B)
T–4
C)
T
D)
T2
2.
Attenuation coefficient of bone is 600 m-1
for x-rays of energy 20 keV and intensity of beam of x-rays is 20 Wm-2,
then intensity of beam after passing through a bone of 4 mm is A) 3 Wm-2
B) 2.5
Wm-2
C) 2.0
Wm-2
D)
1.8 Wm-2
3.
Incident rate is measured by A) Case control study
B)
Cohort study
C)
Cross-sectional study
D)
Intervention study
4.
Systolic BP= a + b (age) +c (BMI) is an example of
A)
Simple linear regression
B)
Simple curvilinear regression
C)
Multiple linear regression
D)
Multiple curvilinear
regression 5. One
gram of a radioactive substance takes 50 seconds to lose 1 centigram. The half
life period of the radioactive substance is
A)
57 minutes
B)
75 minutes
C)
61 minutes
D)
55 minutes
6.
How many half-value layers are required to reduce a
100 R/minute exposure rate to 25 R/minute?
A)
1
B)
2
C)
4
D)
8
7.
A person’s heart is imaged in a diagnostic
procedure. The source to film distance is 100 cm and the object to film
distance is 80cm. How much the heart
will be magnified on the film?
A)
2 times
B)
4 times
C)
6 times
D)
5 times
8.
Initial activity of an I123 sample (t1/2 = 13 h) of thyroid
counts is 480 MBq. After 12 h, measured activity is 20 MBq. Assuming the volume
of the blood is 6l, find biological Halflife.
A)
3
B)
6
C)
9
D)
11 9. What
are the frequencies of L band, X band and S band microwave?
A)
1-2 GHz, 2-4 GHz and 8-12 GHz
B)
1-2 GHz, 8-12 GHz and 2-4 GHz
C)
8-12 GHz, 1-2 GHz and 2-4 GHz
D)
8-12 GHz, 2-4 GHz and 1-2 GHz 10. What does radial function represent in TG
43 protocol?
A)The changes in dose rate with radial distance from the source.
B) The
changes in dose rate with radial distance which takes into account inverse
square function.
C) The
changes in dose rate with radial distance which does not take into account
inverse square function.
D)The changes
in dose rate with radial distance which takes into account inverse square
function and distribution of radioactive materials within the source.
11. Beam spoiler in TBI radiotherapy is
A)
A sheet of Lucite placed in large fields to reduce dose
rate.
B)
A sheet of Lucite placed in large fields to improve
beam penetration.
C)
A sheet of Lucite placed in large fields to reduce
depth of dmax.
D)
A sheet of Lucite placed in large fields to increase
the skin dose. 12. How
will the dose be calculated for extended SSD for electron beam radiotherapy?
A)
Using the virtual SSD
B)
Using the effective SSD
C)
Using inverse square law and virtual SSD
D)
Using inverse square law and effective SSD 13. What are the advantages of green sensitive
film over blue sensitive films? A) Green sensitive films are insensitive to
blue dye.
B) Green
sensitive films are well matched with the screen of GdO2S:Tb which
emits whole 6 series whereas Blue sensitive film is not well matched with it.
C) There
is no perfect matching screen film combination of blue sensitive film whereas
perfect matching screen film combination is available in case of green
sensitive film. D) Blue sensitive films are
sensitive to blue dye.
14.
Point A according Classical Manchester is defined
in Gynecological implants to be a point located
A)
2 cm cephalad of the last end source of uterine tandem
and 2 cm lateral to uterine tandem
B)
2 cm cephalad from the lateral fornix and 2 cm lateral
to the uterine tandem
C)
2 cm cephalad of the external cervical os and 2 cm
lateral to the uterine tandem D) 2cm up from the flange and 2 cm lateral
to the uterine tandem
15.
For stereotactic radiosurgery treatment of AVM, the
minimum imaging modalities requirements are
A)
DSA and MRI
B)
MRI and CT
C)
DSA, MRI and ultrasound
D)
DSA and ultrasound
16.
Acceptable gradient index in Stereotactic
radiosurgery using gamma knife for the determination of quality of treatment
plan is
A)
the ratio of the volume of 20 % and 50 % isodose curves
in the ranges from 1.5 -2.
B)
the ratio of the volume of 25 % and 50 % isodose curves
in the ranges from 2.5 -3.
C)
the ratio of the volume of 10 % and 90 % isodose curves
in ranges from 2.5 -5.
D)
the ratio of the volume of 10 % and 90 % isodose curves
in ranges from 1.5 -2.
17.
The classified worker is defined according to AERB
RPR- 2004 is
A)
Who is likely to receive an effective dose in excess of
1/10 of average annual dose limit.
B)
Who is likely to receive an effective dose in excess of
1/5 of average annual dose limit.
C)
Who is likely to receive an effective dose in excess of
1/10 of average annual dose limit.
D)
Who is likely to receive an effective dose in excess of
3/10 of average annual dose limit.
18.
Radiation
damage is divided into (a) lethal damage, (b) sublethal damage and (c)
potentially lethal damage (PLD). Which of the following statements is true?
A)
PLD will
cause cell death under ordinary circumstances.
B)
PLD cannot
be repaired under ordinary circumstances.
C)
The
variation of post-irradiation conditions cannot enhance PLD repair.
D)
Mitosis
cannot be delayed by suboptimal growth conditions.
19.
In comparing two 6 MV x-ray beams, both 100 cm2
in total area but one having 10x10 cm2 collimator setting and
the other 5x20 cm2, what can
be said about the relative doses at dmax?
A)
The primary dose is higher for a 10x10 field.
B)
The scatter dose is higher for a 10x10 field.
C)
Both the primary and scatter doses are higher for a
10x10 field.
D)
The doses for the two fields will be the same.
20.
Which of the following is not refer to portal
dosimetry using EPIDs
A)
Dose profile measurement
B)
IMRT QA
C)
Patient position verification
D)
MLC alignment verification
21.
When CT images are used for radiotherapy planning,
Hounsfield numbers must be converted to electron densities for use by the dose
calculation algorithms. The relationship between Hounsfield number and electron
density is approximately linear for most tissues except
A)
Lung
B)
Air cavities
C)
Muscle
D)
Bone
22.
The skin dose for a 6 MeV electron beam is lower
than for a 15 MeV electron beam because for the 6 MeV beam there is
A)
More range straggling
B)
Less range straggling
C)
More x-ray contamination
D)
Lower linear energy transfer (LET)
23.
Regarding single-fraction total body irradiation
(TBI)
A)
The dose rate should be relatively high (> 1 Gy/min)
to keep the treatment time as short as possible.
B)
The dose rate should be low (<0 .2="" effects.="" gy="" min="" minimize="" o:p="" side="" the="" to="">
C)
If the treatment is delivered from two lateral fields,
electron boost fields are sometimes used for the chest wall.
D)
The dose should be at least 20 Gy.
24.
A cone-beam scan is taken to set up a cranium in an
image-guided SRS procedure. The IGRT software is capable of calculating both 3D
and 6D couch/corrections. The couch being used for treatment, however, is only
capable of implementing 3D corrections. The calculated corrections for 3D and
6D are different. What is the best course of action? A) Report a bug in the software.
B)
Use the 6D correction factors.
C)
Use the 3D correction factors.
D)
Use the average of the two sets of translations. 25. What is the cause of tongue-and-groove
effect for MLC-based IMRT?
A)
Leaves that are moving too slowly
B)
Leaves that are out of calibration
C)
Adjacent leaves that extend into the field by very
different amounts D) Opposing
leaves that are closed, but are not under the jaw
26. Regarding single-fraction total body
irradiation (TBI)
A)
The dose rate should be relatively high (> 1 Gy/min)
to keep the treatment time as short as possible.
B)
The dose rate should be low (<0 .2="" effects.="" gy="" min="" minimize="" o:p="" side="" the="" to="">
C)
If the treatment is delivered from two lateral fields,
electron boost fields are sometimes used for the chest wall.
D) The
dose should be at least 20 Gy. 27. Which
of the following is used for IMRT plan evaluation?
A)
Dose prescription will be done by the isodose curve
which covers the 95% volume of Planning target volume.
B)
Dose prescription will be done by the normalization
point on ICRU reference points.
C)
Dose prescription will be done by 100% normalization to
the average dose of Planning Target Volume and 95% of prescribed dose should
enclosed the near maximum target volume i.e. 95% PTV and volume of PTV for near
maximum dose i.e. 107% of prescribed dose should be lesser than 2%.
D)
Dose prescription will be done by 100% normalization to
the average dose of Planning Target Volume and 95% of prescribed dose should
enclosed the near maximum target volume i.e. 98% PTV and volume of PTV for near
maximum dose i.e. 107% of prescribed dose should be lesser than 2%.
28.
Chemical shift artifacts are caused by
differences in the
A)
T1 relaxation time
B)
T2 relaxation time
C)
Spin density
D)
Larmor frequency
29.
The Q factor of an ultrasound transducer
describes the
A)
Crystal resonance frequency
B)
Fresnel zone length
C)
frequency response of the crystal
D)
FWHM value of the beam intensity
30.
Which statement is not true of electromagnetic radiation? A) It travels at the speed of light.
B)
It exhibits particulate properties.
C)
Photon energy is proportional to its
frequency.
D)
Wavelength is proportional to the
frequency.
31.
The average photon energy of an x-ray beam
cannot be changed by
A)
Tube current (mA)
B)
Beam filtration
C)
Tube voltage
D)
Voltage waveform
32.
Following absorption of a single 30 keV photon
in a patient
A)
Temperature rises significantly (more than
1°C)
B)
A number of ionization events occur
C)
Several scatter photons emerge
D)
Internal conversion electrons are emitted
33.
The average energy of K-shell characteristic
x-rays are not
A)
About 18 keV for molybdenum anodes
B)
Dependent on the shell structure of the target
atom
C)
Independent on x-ray filtration
D)
Independent of atomic number (Z)
34.
Entrance skin dose for an anterior-posterior
abdominal x-ray examinations is
typically
A)
Below 1 mGy (100 mrad)
B)
1 mGy (100 mrad)
C)
3 mGy (300 mrad)
D)
10 mGy (1 rad)
35.
Which of the following has the shortest T1
value?
A)
Fat
B)
Liver
C)
White matter
D)
Cerebrospinal fluid
36.
A material with an attenuation 5% greater than
that of water has a Hounsfield unit value of
A)
−50
B)
−5
C)
+5
D)
+50
37.
If an average of 10,000 photons are detected per
mm2, the chance of detecting between 9,700 and 10,300 counts in any
exposed mm2 is
A)
67% B) 90% C) 95% D) 99%
38.
A Geiger-Muller detector would be best employed
to A) detect low-level 99mTc contamination
B)
measure the output of an x-ray tube
C)
monitor patient exposures
D) measure
x-ray leakage exposure
39.
A constant potential generator operated at 100
kV and 1,000 mA for 0.1 second deposits
A)
1,000 heat units
B)
1,350 heat units
C)
10,000 heat units
D)
13,500 heat units
40.
The number of electrons accelerated across an
x-ray tube is determined by
A)
Anode speed
B)
Focal spot size
C)
Filament current
D)
X-ray tube voltage
41.
When heated, TLDs emit
A)
X-rays
B)
Photoelectrons
C)
Characteristic x-rays
D)
Light
42.
Patient doses in fluoroscopy can exceed 100
mGy/minute (10 R/minute) if
A)
High kilovolt peak values are used
B)
Exposure time does not exceed 5 minutes
C)
Visible/audible indicators are activated
D)
Contrast agents have been administered
43.
The skin dose for a chest x-ray examinations is
A)
Less than 0.05 mGy (3 mrad)
B)
About 0.05 mGy (3 mrad)
C)
About 0.15 mGy (15 mrad)
D)
About 0.5 mGy (50 mrad)
44.
Which of the following is not a quality control test performed on a gamma camera?
A)
Field uniformity
B)
99Mo breakthrough
C)
Extrinsic flood
D)
Spatial resolution
45.
According to the ALARA concept, annual doses to
x-ray technologists should be
A)
Zero
B)
5 mSv (500 mrem)
C)
50 mSv (5 rem)
D)
As low as possible 46. Which of the following are types of
stochastic effects?
A) Skin erythema
B) Infertility C)
Breast cancer D) Cataracts
47.
The photoelectric
absorption cross-section for alpha-ray is proportion to
A)
Z2
B)
1/ Z2
C)
Z5
D)
Z4
48.
Name the accelerator
which cannot accelerate protons
A)
Betatron
B)
Cyclotron
C)
Synchrotron
D)
Cockcrof Walton accelerator 49. Which of the following statement is
considered a multivariate model?
A)
Height and weight
very together
B)
Height varies with
age, weight, and sex
C)
Height and weight
vary with age and sex
D)
None of the above
50. The LD 50/60 dose for humans is
approximately equal to
A)
1 Gy
B)
4 Gy
C)
10 Gy D) 12 Gy
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