Physics A Questions

A1.

Which of the following is expressed in non-SI units?

(A) Meter

(B) Roentgen

(C) Kilogram

(D) Second

(E) Becquerel

(F) Sievert

A2.

Match the quantity with the units in which it is measured.

(A) Absorbed dose

(B) Power

(C) Exposure

(D) Activity

(E) Dose equivalent

(i) Becquerel

(ii) Watt

(iii) C/kg

(iv) Gray

(v) Sievert

A3.

Match the atomic number with the correct element.

(A) 29

(B)  42

(C)  50

(D)  74

(i) Tin

(ii) Tungsten

(iii) Copper

(iv) Molybdenum

A4.

Outer-shell electrons differ from K-shell electrons by their

(A) rest mass energy

(B) charge

(C) magnetic moment

(D) binding energy

(E) none of the above

A5.

Match the following particles and masses.

(A) Electron

(B) Alpha particle

(C) Neutrino

(D) Proton

(i) 4AMU

(ii) 1AMU

(iii) (1/1836) AMU

(iv) zero mass

A6.

Match the wavelength with the type of wave.

(A) 10^-10 meters

(B) 7 meters

(C) 0.001 meters

(D) 5 x 10^-7 meters

(i) Visible light

(ii) Diagnostic x-rays

(iii) Ultrasound

(iv) MRI signal (1 tesla)

A7.

Ionizing radiations include all of the following EXCEPT

(A) photons

(B) electrons

(C) neutrons

(D) alpha particles

(E) pulsed ultrasound waves

A8.

True (T) or False (F).

In the following transformations

(A) beta minus decay, Z increases by 1

(B) beta minus decay, A increases by 1

(C) beta plus decay, Z increases by 1

(D) isomeric transitions, A and Z remain constant

(E) alpha decay, Z decreases by 2

A9.

Match the particle with the description.

(A) Nucleus of a hydrogen atom

(B)  Emitted during electron capture

(C) Created during pair production

(D) Source of electric currents

(E) Produced during decay of ²²²Rn (radon)

(i) Proton

(ii) Neutrino

(iii) Positron

(iv) Alpha particle

(v) Electron

A10.

An activity of 10 mCi corresponds to

(A) 3.7 kBq

(B) 37O kBq

(C) 3.7 MBq

(D) 370 MBq

(E) 3.7 GBq

A11.

Full-wave, compared with half-wave rectification

(A) requires no diodes in the rectification circuit

(B) reduces the voltage ripple

(C) delivers the same radiation output in half the time

(D) increases the effective energy of the beam

(E) reduces the heel effect

A12.

50 keV electrons striking tungsten CANNOT lose energy by

(A) K-shell characteristic x-ray production

(B) L-shell characteristic x-ray production

(C) Bremsstrahlung x-ray production

(D) excitation and ionization of outer-shell electrons

A13.

The cloud of electrons surrounding an x-ray tube filament is called

(A) a space charge

(B) a diode

(C) a grid

(D) an impurity

(E) none of the above

A14.

Tungsten (Z = 74) is used for the target of most x-ray tubes rather than lower Z materials because

(A) shorter wavelength x-rays are produced

(B) the intensity of the resulting x-ray beam is high

(C) there is no characteristic radiation from tungsten

(D) x-rays from tungsten are emitted toward the patient

(E) the heel effect is minimized with tungsten targets

A15.

An x-ray beam produced by monoenergetic 90 keV electrons striking a tungsten target. Match the statements below.

(A) Electron beam energy converted to heat

(B) Electron beam energy converted to x-rays

(C) Total x-ray and heat energy

(D) X-rays accounted for by characteristic x-rays

(i) 1%

(ii) 10%

(iii) 100%

(iv) 99%

A16.

A focal-spot rating is defined as the product of the maximum kV and mA for an exposure time of

(A) 0.01s

(B) 0.1s

(C) 1s

(D) no exposure time needs to be specified

A17.

The x-ray tube mAs mainly controls image

(A) density

(B) resolution

(C) speed

(D) magnification

A18.

The heel effect results in the greatest x-ray beam intensity

(A) at the anode edge

(B) at the cathode edge

(C) in the middle of the field

(D) transmitted through the collimator

(E) transmitted through the x-ray tube housing

A19.

Pair production interactions

(A) have no threshold

(B) occur in the electric field of the nucleus

(C) produce 1.022 MeV annihilation radiation

(D) are important in radiology

(E) all of the above

A20.

After photoelectric interactions, the following emission CANNOT occur.

(A) Photoelectrons

(B) Scattered photons

(C) Characteristic x-rays

(D) Auger electrons

A21.

True (T) or False (F).

Concerning the photoelectric effect and Compton scatter in water

(A) photons may undergo two successive photoelectric effects

(B) Compton scatter has a threshold energy of 1.022 MeV

(C) at diagnostic x-ray energies, the photoelectric effect increases with photon energy

(D) the photoelectric and Compton effects are equal at 25 keV

A22.

The energy of the scattered photon in Compton processes primarily depends on the

(A) atomic number

(B) density

(C) electron density

(D) molecular structure

(E) scattering angle

A23.

In the following situations, which interaction predominates:

photoelectric effect; Compton scatter; coherent scatter?

(A) 28 kVp in soft tissue

(B) 60 kVp in bone

(C) 100 kVp in soft tissue

(D) 100 kVp in iodine contrast

(E) 100 kVp in LaOBr intensifying screen

A24.

If the linear attenuation is 0.1 cm^-1, and the density is 2 g/cm³, then the mass attenuation coefficient is

(A) 0.2 cm2/g

(B) 0.05 cm2/g

(C) 0.05 g/cm2

(D) 20g/cm2

(E) cannot be determined

A25.

Increasing aluminum filtration will generally lead to increased

(A) subject contrast

(B) x-ray output

(C) tube heat loading

(D) entrance skin exposure

(E) phototimed film densities

A26.

X-ray beam quality is

(A) directly proportional to the tube current (mA)

(B) reduced by additional x-ray beam filtration

(C) measured in mm of aluminum

(D) used to convert dose (Gy) to dose equivalent (Sv)

(B) independent of the applied kV and wave-form

A27.

Subject contrast depends on

(A) kVp

(B) tube current (mA)

(C) type of film

(D) development time and temperature

(E) film density

A28.

Which of the following is the non-SI unit of dose equivalent?

(A) Roentgen

(B) Rad

(C) Rem

(D) RBE

(E) None of the above

A29.

The quality factor (QF) is used to

(A) convert rem to sievert

(B) convert absorbed dose to dose equivalent

(C) determine the linear energy transfer (LET)

(D) determine the relative biological effectiveness

(E) all of the above

A30.

Match the tissue with the appropriate f-factor (rad/R) for an 80 kVp diagnostic x-ray beam.

(A) Fat

(B) Muscle

(C) Bone

(i) 0.9

(ii) 3.0

(iii) 0.6

A31.

Match the SI unit with the corresponding non-SI unit.

(A) Gray

(B) Becquerel

(C) Sievert

(D) Coulomb/kg

(E) Joule

(i) Rem

(ii) Rad

(iii) Curie

(iv) Erg

(v) Roentgen

A32.

How will an increase in developer temperature generally affect the resultant film density?

(A) Increase density

(B) No change

(C) Reduce density

(D) Cannot be determined

A33.

Match the following examinations with the appropriate type of film.

(A) High gradient

(B) Wide latitude

(C) Fast

(i) Chest x-ray examination

(ii) Abdomen examination

(iii) Mammography examination

A34.

Films with high contrast CANNOT have

(A) low fog

(B) low noise

(C) wide latitude

(D) high speed

(E) high resolution

A35.

Match each instrument to the measurement procedure, using each option only once.

(A) Survey for radionuclide contamination

(B) X-ray tube output

(C) Personnel monitoring

(D) Xeroradiograph

(i) Geiger-Muller (GM) meter

(ii) Thermoluminescent dosimeter (TLD)

(iii) Ionization chamber survey meter

(iv) Charged selenium plate

A36.

The ratio of the x-ray exposures without a screen to the corresponding exposure with screen is called the

(A) resolving power

(B) intensification factor

(C) exposure ratio

(D) Bucky ratio

(E) conversion ratio

A37.

Matching the K-edge of the intensifying screen with the energy of incident x-ray improves the

(A) conversion efficiency

(B) spatial resolution

(C) subject contrast

(D) image contrast

(E) none of the above

A38.

True (T) or False (F).

Regarding screen film combinations

(A) LaOBr emits mainly blue light

(B) Gd2O2S emits mainly green light

(C) CaWO4 emits mainly blue light

(D) Ortho film is sensitive to green light

(E) Most radiographic films are sensitive to red light

A39.

What determines grid efficiency of removal of scattered radiation?

(A) Grid ratio

(B) Focus distance

(C) Gap distance

(D) Strip height

(E) None of the above

A40.

The ability of an imaging system to reproduce fine detail in the image is best characterized by the system

(A) x-ray absorption efficiency

(B) spatial frequency

(C) modulation transfer function

(D) quantum mottle

(E) magnification

A41.

For a film with a gradient of 2.0, a 3-cm nodule in the lung will reduce film density by about

(A) <0.01

(B) 0.1

(C) 0.6

(D) >2.0

A42.

Focal spot size affects image quality by modifying

(A) resolution in contact radiography

(B) resolution in magnification radiography

(C) patient entrance skin exposure

(D) image noise

(E) film latitude

A43.

Film image contrast may be reduced by

(A) increasing developer temperature

(B) lowering kVp

(C) using a grid

(D) reducing beam filtration

(E) none of the above

A44.

Doubling screen thickness is likely to increase the

(A) exposure time

(B) patient dose

(C) fraction of x-ray photons absorbed

(D) film processing time

(E) image noise

A45.

Match the following grid ratios with the most likely application.

(A)  Magnification mammography

(B)  Barium study

(C) Screen/film mammography

(D) Portable abdomen

(i) 4:1

(ii) 6:1

(iii) 12:1

(iv) None

A46.

Which of the following does NOT affect image noise for a given film density?

(A) Intensifying screen conversion efficiency

(B) Film processor temperature

(C) Film speed

(D) Screen thickness

A47.

Match the technique change with its most likely effect on a phototimed radiographic image.

(A) Increase kVp but same mA

(C)  Increase the grid ratio

(i) Increased motion blur

(ii) Improved contrast

(iii) Reduced spatial resolution

(iv) Reduced contrast

A48.

Compared to screen/film, computed radiography has

(A) the potential to reduce patient doses

(B) reduced spatial resolution

(C) image processing capabilities

(D) the ability to store data digitally

(E) all of the above

A49.

Match the fluorescent phosphor with imaging modality.

(A) Nal

(B)  CsI

(i) Screen/film radiography

(ii) Fluoroscopy

(iii) Nuclear medicine

A50.

The photocathode of an image intensifier converts

(A) electrons to light

(B) x-rays to light

(C) x-rays to electrons

(D) electrons to x-rays

(E) none of the above

A51.

All of the following degrade image quality in image intensifiers EXCEPT

(A) vertically oriented CsI crystals

(B) pincushion distortion

(C) vignetting

(D) misaligned electronic focussing lens

(E) x-rays impinging on the output phosphor

A52.

Fluoroscopic entrance skin exposures are normally

(A) equal to a few R/min

(B) not allowed to exceed 10 R/min

(C) dependent on the kV used

(D) dependent on the II size

(E) all of the above

A53.

A noisy fluoroscopic image is most likely to be improved by increasing the

(A) focal spot size

(B) x-ray beam filtration

(C) grid ratio

(D) exposure level

(E) monitor gain

A54.

To perform cine studies, a fluoroscopic system would require addition of all the following EXCEPT

(A) x-ray tube voltages 150 kVp

(B) grid controlled x-ray tube

(C) synchronization circuit

(D) cine camera

(E) optical distributor

A55.

What is the pixel size if a 256*2 matrix is used to image a 25 cm-wide field?

(A) 0.5mm

(B) 1mm

(C) 2mm

(D) None of the above

A56.

Basic computation in a computer is performed by the

(A) random access memory (RAM)

(B) read only memory (ROM)

(C) central processing unit (CPU)

(D) small computer system interface (SCSI)

(E) none of the above

A57.

True (T) or False (F).

Regarding computer memory

(A) RAM is used for permanent memory

(B)  buffer memory is used for temporary storage

(D)  magnetic tapes have access times of less than 1 msec

(E) optical jukeboxes can have a storage capacity of over 10*12 Bytes

A58.

An efficient picture archive and communication system (PACS) should reduce all of the following EXCEPT

(A) use of film

(B) lost images

(C) use of viewboxes

(D) radiology capital costs

(E) film library clerks

A59.

Match the imaging modality with the appropriate limiting spatial resolution.

(A) Digital subtraction angiography

(B) Magnetic resonance imaging

(C) Computed tomography

(D) Nuclear medicine

(E) Computed radiography

(i) 3 line pairs/mm

(ii) 2 line pairs/mm

(iii) 0.7 line pairs/mm

(iv) 0.3 line pairs/mm

(v) <0.1 line pairs/mm

A60.

The Hounsfield unit (HU) assigned to pixel in a clinical CT image may be significantly affected by all of the following tissue factors EXCEPT

(A) density

(B) electron density

(C) atomic number

(D) homogeneity

(E) temperature

A61.

Increasing the CT image matrix from 256*2 to 512*2, at a fixed kV and mAs, may be expected to increase the

(A) patient throughput

(B) x-ray tube loading

(C) patient dose

(D) limiting spatial resolution

(E) film printing time

A62.

Increasing the kV alone in CT scaning reduces

(A) anode loading

(B) subject contrast

(C) partial volume effects

(D) reconstruction time

(E) all of the above

A63.  

Which of the following artifacts does not appear in CT images?

(A) Motion artifacts

(B) Phase-encoding artifacts

(C) Streak artifacts

(D) Ring artifacts

(E) Beam-hardening artifacts

A64.

The limiting spatial resolution in CT is affected by all of the following EXCEPT

(A) field of view

(B) detector aperture size

(C) mA

(D) matrix size

(E) focal spot size

A65.

Increasing the width of the CT image display window will reduce

(A) displayed contrast

(B) quantum mottle

(C) section thickness

(D) field of view

(B) none of the above

A66.

CT beam-hardening artifacts

(A) reduce CT numbers in the image center

(B)  are independent of x-ray beam filtration

(C) reduce all CT numbers

(D) do not occur on 4th generation scanners

(E) none of the above

A67.

Give "ballpark" values for each of the following levels of radioactivity.

(A) Detection limit using a Geiger meter

(B) Administered for thyroid uptake assessment

(C) Administered for nuclear medicine (NM) imaging procedure

(D) Technetium-99m generator

(E) Cobalt-60 radiotherapy source

(F) Released during the Chernobyl disaster

A68.

Technetium generators

(A) are eluted with sterile water

(B) last for 67 hours

(C) have 99Tc as the parent radionuclide

(D) can be eluted on a daily basis

(E) can be disposed of in the regular garbage after use

A69.

The Nal crystals routinely used in gamma cameras

(A) are between 6 and 12 mm thick

(B) have high photoelectric absorption at 140 keV

(C) convert about 5% of absorbed energy into light

(D) result in an intrinsic resolution of 3 mm FWHM

(E) all of the above

A70.

Increasing the distance between the patient and a parallel hole collimator results in

(A) reduced resolution

(B) reduced field of view

(C) increased patient dose

(D) image distortion

(E) all of the above

A71.

Using radionuclides with a higher photon energy generally increases

(A) detector efficiency

(B) septal penetration

(C) amplifier gain setting

(D) image magnification

(E) resolution

A72.

Which of the following nuclear medicine studies require a computer?

(B)  Liver scan

(D)  Thyroid uptake

(E) All of the above

A73.

All of the following factors will affect the organ dose for a radioisotope study EXCEPT the

(A) organ size

(B) organ shape

(C) uptake of isotope

(D) clearance of isotope

(E) gamma camera imaging time

A74.

True (T) or False (F).

When estimating the therapeutic thyroid dose following administration of 131I, the following data are essential.

(A) Activity administered to the patient

(B) r factor for 131I (Gy/Bq at 1 meter)

(C) Fractional uptake by the thyroid

(D) Thyroid mass

(E) Biological clearance of activity from thyroid

A75. Radiopharmaceuticals can suffer from all of the following impurities EXCEPT

(A) radionuclide

(B) crystal

(C) chemical

(D) biological

(E) all of the above

A76.

In SPECT imaging

(A) resolution is generally superior to CT

(B) imaging times are typically < 2 minutes

(C) annihilation radiation is detected in coincidence

(D) multiple views must be obtained

(E) scatter and attenuation corrections are never needed

A77.

Positron emission tomography (PET) scanners generally make use of all of the following EXCEPT

(A) short-lived radionuclides such as 15O

(B) cyclotrons

(C) directly detected positrons

(D) filtered-back projection reconstruction algorithms

(E) solid-state detectors

A78.

Following an acute whole body exposure of 1 Gray (100 rad), the following is likely to be observed.

(A) Erythema

(B) Diarrhea

(C) Reduced lymphocyte count

(D) Permanent sterility

(E) Death within 60 days

A79.

Exposure to x-rays

(A) during the first 10 days post conception can result in embryo death

(B) between 20 days and 40 days post conception can cause fetal deformations

(C) during the second trimester can cause growth retardation

(D) during the third trimester increases childhood cancers

(E) all of the above

A80.

Match the skin dose with the radiographic examination.

(A)  30 mGy (3 rad)

(B)  0.1 mGy (10 mrad)

(C) 3 mGy (300 mrad)

(i) Chest x-ray (PA)

(ii) Abdominal x-ray

(iii) 1 minute of fluoroscopy

A81.

After a single-view lateral lumbar spine x-ray examination (600 speed screen/film combination), a woman discovers she is pregnant. The radiation dose to the fetus is likely to

(A) be sufficient that the woman will require an abortion

(B) exceed 100 mGy (10 rad)

(C) exceed 10 mGy (1 rad)

(D) be less than 10 mGy (< 1 rad)

(E) be difficult to assess

A82.

The ALARA concept requires that design of an x-ray facility should ensure that

(A) doses be kept as low as reasonably achievable

(B) all unnecessary x-rays should be avoided

(C) account be taken of social and economic factors

(D) doses received by patients be minimized

(E) all of the above

A83.

Lead aprons for radiographers

(A) should be worn at the radiographic control panel

(B) have a higher lead equivalence than for nuclear medicine technologists

(C) are generally 0.50 mm in lead equivalence

(D) reduce the thyroid dose

(E) reduce exposure from radon

A84.

Leaded glasses are required

(A) to have an attenuation equivalent of 5 mm lead

(B) for all radiographic exposures

(C) for all fluoroscopic exposures

(D) none of the above

A85.

True (T) or False (F).

222Rn (radon)

(A) is a product of 226Ra

(B) concentrates in poorly ventilated basements

(C) can cause lung cancer

(D) is a pure beta emitter

(E) has a half-life of greater than 1 year

A86.

Increasing the ultrasound frequency from 1 MHz to 10 MHz usually reduces the

(A) material acoustical impedance

(B) beam penetration

(C) material viscosity

(D) lateral resolution

(E) beam velocity

A87.

An ultrasound beam intensity attenuated by 3 dB is how much lower than the original signal?

(A) 3%

(B) 30%

(C) 50%

(D) 97%

(E) Depends on the ultrasound velocity

A88.

Signal attenuation in ultrasound is

(A) normally measured in decibels

(B) very high in the lung

(C) proportional to frequency

(D) about 1 dB/cm at 1 MHz in soft tissue

(E) all of the above

A89.

Refraction of an ultrasound beam refers to the

(A) change of beam frequency

(B) multiple reflections at two interfaces

(C) loss of signal intensity

(D) change in direction of the beam at an interface

A90.

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

(E) power penetration into patient

A91.

True (T) or False (F).

The following generally improve the transmission of ultrasound into the patient.

(A) Quarter-wave matching layer

(B) Time gain compensation (TGC)

(C) Gel applied to the transducer

(D) Scan converter

A92.

Time gain compensation (TGC) compensates for tissue attenuation by increasing the

(A) transducer output

(B) echo intensity

(C) focal zone length

(D) echo velocity

(E) all of the above

A93.

Clinical ultrasound beams may have all the following EXCEPT

(A) frequencies of several MHz

(B) velocities of 1540 m/s in tissue

(C) wavelengths of about 0.5 mm

(D) pulse repetition frequencies (PRF) of 100kHz

(E) pulses contain only a few wavelengths

A94.

Increasing the ultrasound pulse length will generally reduce the

(A) axial resolution

(B) amount of power deposited in the patient

(C) acoustical impedance

(D) transducer Q factor

(E) lateral resolution

A95.

A Doppler ultrasound examination can use

(A) specular reflections to characterize tissue

(B) pulsed ultrasound to eliminate aliasing

(C) continuous ultrasound to measure flow

(D) echo amplitude to measure impedance

(E) time to measure interface depth

A96.

True (T) or False (F).

(A) All naturally occurring nuclei have magnetic moment

(B) Protons in magnetic fields precess at the Larmor frequency

(C) Protons aligned parallel to the field have higher energy than those aligned antiparallel

(D) Most protons in a region contribute to the MR signal

A97.

The Larmor equation in MR involves all of the following EXCEPT

(A) magnetic field strength

(B) gyromagnetic ratio for nucleus of interest

(C) nuclear precession frequency

(D) spin-spin relaxation rate

A98.

Following a 90-degree RF pulse, spins in a uniform magnetic field will likely lose their phase coherence in a time comparable to

(A) T1

(B) T2

(C) TE

(D) TI

(E) TR

A99.

True (T) or False (F).

For commercial whole body MR magnets

(A) resistive magnets need coolant to dissipate heat

(B) resistive magnets have a maximum strength of 2 T

(C) permanent magnets have small fringe fields

(D) permanent magnets are generally very heavy

(E) superconducting magnets have uniformities approaching 1 part per million (ppm)

(F) superconducting magnets have field strengths up to 4 T

A100.

The RF coils used in proton MR imaging do NOT

(A) resonate at about 42 MHz at 1 T

(B) emit RF pulses of short duration

(C) detect RF signals

(D) require water cooling

A101.

Which of the following items is not affected by a nearby MRI system?

(A) Cardiac pacemaker

(B) Nuclear medicine gamma camera

(C) Credit card

(D) Image intensifier

(E) Optical densitometer

A102.

True (T) or False (F).

In MR imaging

(A) the RF frequency used is dependent on patient size

(B) T1 for fluids is very long

(D) At 1T, proton signal strength is stronger than 31P

(E) tumors generally have longer relaxation times than normal tissue

A103.

MRI reconstruction algorithms commonly use

(A) two-dimensional Fourier transforms

(B) K-space Hankel transforms

(C) patient motion corrections

(D) algebraic reconstruction techniques (ART)

(E) all of the above

A104.

The appearance of CSF on a conventional spin echo image with T2 weighting is

(A) isointense with gray matter

(B) darker than white matter

(C) very bright

(D) very dark

(E) cannot be determined

A105.

Increasing the main magnetic field will increase all of the following EXCEPT

(A) T1

(B) T2

(C) signal-to-noise ratio

(D) MRI system cost

(B) proton resonance frequency

A106.

Match the T1 relaxation time (at 1 tesla) with the tissue type.

(A) 260ms

(B) 650 ms

(C) 2400 ms

(i) CSF

(ii) Fat

(iii) Kidney

A107.

Match the T2 relaxation time with the tissue type.

(B) 9Oms

(C) l8Oms

(i) White matter

(ii) Cerebrospinal fluid

(iii) Liver

A108.

All of the following effects give rise to artifacts in MRI EXCEPT

(A) susceptibility changes

(B) motion

(C) chemical shifts

(D) refraction

(E) undersampling

A109.

Match the physical density with the tissues found in the breast.

(A) 0.9 g/cm3

(B) 1.04 g/cm3

(C) 1.05 g/cm3

(D) 2.2 g/cm3

(i) Calcification

(ii) Adipose

(iii) Fibroglandular tissue

(iv) Carcinoma

A110.

Mammography examinations use a low kVp primarily to

(A) reduce x-ray tube loading

(B) increase subject contrast

(C) increase the importance of Compton effects

(D) reduce the importance of photoelectric effects

(E) reduce the patient dose

A111.

Screen/film mammography uses all the following EXCEPT

(A) half-wave rectification

(B) low kVp (25-35)

(C) molybdenum targets

(D) beryllium windows

(E) molybdenum filtration

A112.

Grids in mammography may increase all the following EXCEPT

(A) breast dose

(B) image contrast

(C) x-ray tube loading

(D) object contrast

(E) exposure time

A113.

American College of Radiology accreditation of breast imaging centers involves all the following EXCEPT

(A) documentation of a quality control program

(B) assessment of image quality using a phantom

(C) independent evaluation of clinical images

(D) weekly measurement of kVp

(E) annual evaluations by a medical physicist

A114.

Match the following mammographic imaging methods with the appropriate technical components and setting.

(A) Screen/film

(B) Xeromammography

(C) Magnification

(D) Two images at +/- 15 degrees

(i) 45 kVp, tungsten target, Al filter

(ii) 0.1 mm focal spot

(iii) 28 kVp, Mo target, Mo filter

(iv) Stereotactic localization

A115.

Advantages of ultrasound for breast imaging include all of the following EXCEPT

(A) differentiation of cysts from solids

(B) no ionizing radiation

(C) noninvasive

(D) good visualization of micrcocalcifications

A116.

All of the following imaging modalities have been used for breast imaging EXCEPT

(A) thermography

(B) magnetic resonance imaging

(C) ultrasound

(D) electron microscopy

(E) diaphanography

A117.

If the average number of photons detected in a mm*2 is 10,000, the chance of detecting between 9700 and 10,300 counts in any exposed mm*2 is

(A) 67%

(B) 90%

(C) 95%

(D) 99%

(E) insufficient data to perform calculation

A118.

If 100 photons strike each square mm of an imaging system, the corresponding signal-to-noise ratio (SNR) per mm*2 is

(A) > 100:1

(B) 100:1

(C) 10:1

(D) 1:1

(E) cannot be determined

A119.

 Match the following.

(A) High specificity

(B) High sensitivity

(C) High accuracy

(i) High true-negative fraction (TNF)

(ii) Low false-positive (FPF) and false-negative fractions (FNF)

(iii) High true-positive fraction (TPF)

A120.

Adjusting a decision threshold to increase the sensitivity will normally result in an increase in the

(A) area under the ROC curve

(B) false-positive fraction

(C) specificity

(D) accuracy

(E) none of the above