Medical Imaging Flashcards by Daniel Hikry

CAT-scan tomographies are taken in which anatomical plane?

a. Sagital
b. Transverse
c. Frontal
d. Parasagittal

b. Transverse

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The position of spectral lines of characteristic X-rays depends on…

a. The accelerating voltage
b. The type of anode material
c. The type of cathode material
d. The temperature of the cathode

b. The type of anode material

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What is the unit of mass attenuation coefficient?

a. l/cm
b. g/cm2
c. cm2/g
d. W/cm2

c. cm2/g

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The reflection of ultrasound

a. Is fundamental in aquiring the diagnostic information
b. Decreases the sharpness of the image, so it should be avoided
c. Depends only on the stiffness of the reflecting surface
d. Depends only on the angle of incidence of the ultrasound

a. Is fundamental in aquiring the diagnostic information

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Why are the fetal hears sounds audible during Doppler US examination?

a. Because the frequency of the reflected sound falls in the audible range
b. Because the Doppler detector operates as a microphone
c. Because the difference of the incident and reflected frequency falls in the audible range
d. Because the ratio of incident and reflected frequency falls within the audible range

c. Because the difference of the incident and reflected frequency falls in the audible range

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Select the correct statement

a. Both SPECT AND PET are anatomical imaging methods
b. We detect photons in case of both SPECT and PET
c. In case of PET we detect directly positrons
d. Isotopes used in PET have long half life

b. We detect photons in case of both SPECT and PET

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What is the advantage of multimodal imaging?

a. It combines two anatomical imaging methods (CT, MRI) to indicate accurate anatomical details
b. It does not have any due to the low number of multimodal contrast materials
c. It combines functional imaging on the level of cellular processes with accurate anatomical localization
d. It is just a fashionable diagnostic trend without any apparent advantages

c. It combines functional imaging on the level of cellular processes with accurate anatomical localization

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Which of the following isotopes is NOT gamma emitting?

a. I-123
b. I-131
c. Tc-99m
d. F-18

d. F-18

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What is the aim of the so called windowing method?

a. It means the application of a certain filter
b. To display a narrower range of observed values
c. To snatch a detail of the image
d. To enlarge a detail of the image

b. To display a narrower range of observed values

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Select the wrong statement on spin-spin relaxation

a. It is also called T2 relaxation
b. It refers to the interaction between an elementary magnet and its environment
c. We measure the temporal change of magnetic vector projection perpendicular to the external magnetic field
d. The amplitude of the measured signal decreases with time

b. It refers to the interaction between an elementary magnet and its environment

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An ultrasound diagnostic device has a 3.5 and a 5 MHz transducer. Which of them has greater effective range?

a. The one with 3.5 MHz
b. The one with 5 MHz
c. Their ranges are equal
d. Range depends on acoustic impedance

a. The one with 3.5 MHz

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The basis of ultrasonic imaging:

a. Is the reflection of ultrasound on the boundary between tissues of different acoustic impedance
b. Is the difference in ultrasound absorption of different tissues
c. Is the change in ultrasound speed and wavelength in different tissues
d. Is the thermal effect of ultrasound

a. Is the reflection of ultrasound on the boundary between tissues of different acoustic impedance

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During contrast manipulation

a. The difference between the brightest and darkest pixels displayed on the image does not change
b. The difference between the brightest and darkest pixels displayed on the image either decreases or increases
c. The difference between the brightest and darkest pixels displayed on the image increases always
d. The difference between the brightest and darkest pixels displayed on the image decreases always

b. The difference between the brightest and darkest pixels displayed on the image either decreases or increases

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Select the correct statement:

a. US is high frequency electromagnetic radiation
b. US is a mechanical wave with wavelength much longer than that of the audible sound range
c. US is a mechanical wave with frequencies much less that that of the audible sound range
d. US is a mechanical wave with frequencies many times ten-thousand Hz or even more

d. US is a mechanical wave with frequencies many times ten-thousand Hz or even more

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Which statement is false?

a. Normally alpha-emitting isotope is used in nuclear imaging for its sufficient distance in body tissue
b. Purely gamma radiating isotopes are preferred in isotope diagnostics to avoid the unnecessary exposure to alpha and beta radiation
c. One way of producing pure gamma radiating isotopes is the technetium generator
d. Tc-99m is an ideal radioisotope for diagnostic imaging

a. Normally alpha-emitting isotope is used in nuclear imaging for its sufficient distance in body tissue

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Which statement is correct?

a. Bremsstrahlung is electromagnetic radiating with continuous spectrum produced by the deceleration of high velocity charged particles
b. Bremsstrahlung is electromagnetic radiation with line spectrum produced by deceleration of high velocity charged particles
c. Bremsstrahlung is produced after the ionization when electrons accelerated to high energies collide with electrons in the anode material
d. The position of the maximum point of Bremsstrahlung spectrum is characteristic of the anode material

a. Bremsstrahlung is electromagnetic radiating with continuous spectrum produced by the deceleration of high velocity charged particles

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What is the advantage of multimodal imaging?

a. Allows integration of the strengths of individual modalities (functional and anatomical), while overcoming their limitations
b. It has no advantage other than being cost-effective
c. It is easier to use than other imaging techniques
d. At the moment it has no advantage as multimodal contrast material does not exist

a. Allows integration of the strengths of individual modalities (functional and anatomical), while overcoming their limitations

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What does the absorption coefficient of ultrasound depend on linearly?

a. On the wavelength of the ultrasound
b. On the pulse repetition frequency
c. On the frequency of the ultrasound
d. On the thickness of the layer of the medium

c. On the frequency of the ultrasound

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Optical imaging is used for what purpose even today?

a. For nothing
b. For the examination of tympanic cavity
c. For the examination of renal function
d. For ocular examination (with OCT technique)

d. For ocular examination (with OCT technique)

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What isotope would you use for a SPECT examination?

a. Beta(-)radiation isotope
b. Beta(+)radiation isotope
c. Gamma radiation isotope
d. SPECT does not use isotopes

c. Gamma radiation isotope

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In which technique is microbubble contrast material used?

a. SPECT
b. PET
c. MRI
d. Sonography

d. Sonography

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What can lead to an artifact in a CT-image?

a. Metal plates
b. Attenuation of X-rays due to air in the lungs
c. Usage of a contrast material

a. Metal plates

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Which technique can NOT be used to increase image quality?

a. Convolution
b. Median Filtration
c. Filtration with a Gaussian kernel
d. Fourier transformation

c. Filtration with a Gaussian kernel

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What is the definition of acoustic impedance?

a. It is the change of the propagation speed of US when the beam enters a new medium
b. The change of the intensity of US radiation upon entering a new medium
c. The ratio of the incident and reflected intensity
d. The product of the speed of propagation and the density of the medium

d. The product of the speed of propagation and the density of the medium

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What makes Doppler US-examination suitable for blood flow rate determination? a. The absorption of ultrasound depends on the flow rate b. The flow rate depends on the diameter of the blood vessel c. The frequency shift of scattered ultrasound depends on the speed of flowing cells d. The reflectance depends on the flow rate

c. The frequency shift of scattered ultrasound depends on the speed of flowing cells

Which radiation is NOT ionizing radiation? a. α-radiation b. γ-radiation c. ultrasound radiation d. ultraviolet radiation

c. ultrasound radiation

Which statement is correct for molecular imaging? a. It is a type of anatomical imaging b. Cells and processes at cellular level can be examine ex-vivo c. It is an expensive technique d. Cells and processes at cellular level can be examined in-vivo

d. Cells and processes at cellular level can be examined in-vivo

What is the disadvantage of the thallium-201 heart scan? a. The atomic number of Tl-201 is too high so it is only poorly accumulated in the heart b. It poses relatively high exposure c. It doesn’t remain in the heart for long so it can only be used throughout a few ECG- cycles d. The radiation is absorbed poorly so that image of the heart cannot be reconstructed well

b. It poses relatively high exposure

What does the absorption coefficient of ultrasound depend on linearly? a. On the wavelenght of US b. On the pulse repitition frequency c. On the frequency of the US d. On the thickness of the layer of the medium

c. On the frequency of the US

What is the piezoelectric effect? a. The deformation of certain crystals leads to electric currents b. Certain crystal are deformed by electricity c. The volume of certain crystals is reduced by electricity d. Certain crystals generate an alternating current due to increased pressure

a. The deformation of certain crystals leads to electric currents

Synchronisation of the respiratory cycle a. Is only possible in a PET b. Increases the quality of the image because all pictures are in same phase c. Reduces the radiation dose required during the imaging process

b. Increases the quality of the image because all pictures are in same phase

What does an image contain? a. All information of an object b. The optical characteristics of an object c. The spatial distribution of some quality of the object d. It does not provide any information

c. The spatial distribution of some quality of the object

What is the unit of acoustic impedance? a. It is unitless b. Kg/(m2*s) c. Cm/g2 d. Photons

b. Kg/(m2*s)

What is meant by voxel? a. Volumetric unit in imagery b. Pixels of an MRI c. Pixel formation d. Unit of magnetic moment

a. Volumetric unit in imagery

Pick the correct statement a. Fourier-transformation can be used advantageously in diagnostic image formation to identify sharp contrast changes or to spot edges b. Fourier-transformation describes the information content of a two-dimensional image with a one-dimensional frequency function c. According to Fourier’s principle every periodic function can be reproduced by the product of a sine function and its overtones d. Fourier-transformation can be used advantageously in diagnostic image formation to precisely reproduce lost image information

a. Fourier-transformation can be used advantageously in diagnostic image formation to identify sharp contrast changes or to spot edges

Which statement is true? a. Resolution is defined by the number of lines that are identifiable in 1 cm b. Resolution is defined as the shortest distance between two points on a specimen that can still be distinguished as two separate points c. Resolution is defined as the highest magnification of a microscope d. Resolution is not used in the field of radiology, instead sensitivity is used

b. Resolution is defined as the shortest distance between two points on a specimen that can still be distinguished as two separate points

What information does an MRI examination give? a. Proton density b. Mass attenuation coefficient c. Linear attenuation coefficient d. Acoustic impedance

a. Proton density

In which case does not the spectral composition of x-radiation change? a. If the accelerated voltage is changed b. If the anode current is changed c. If the anode material is changed d. If a filter is used

b. If the anode current is changed

Which of the following imaging methods poses the greatest radiation exposure? a. Chest radiography b. Bone scintigraphy c. Abdominal CAT scan d. MRI

c. Abdominal CAT scan

Which is true during PET? a. The gamma photons generated by pair formation (production) are detected b. The gamma photons generated by pair destruction (annihilation) are detected c. The gamma rays emitted from isotopes administered to the patient are detected d. Due to the rontgen absorbance layer images are formed

b. The gamma photons generated by pair destruction (annihilation) are detected

Which organs/tissues can NOT be examined by virtual endoscopy? a. Brain b. Colon c. Bone d. Bronchi

c. Bone

For what radiation is exposure valid? a. Only for alpha and neutron radiations b. Only for beta positive and beta negative radiations c. Only for x and gamma radiations under 3meV d. For any ionizing radiation

c. Only for x and gamma radiations under 3meV

Which statement is true? a. The spectrum of the characteristic x-radiation is continuous and the maximum wavelength does not depend on the anode material b. The spectrum of the characteristic x-radiation is continuous and the maximum wavelength depends on the anode material c. The spectrum of the characteristic x-radiation is a line spectrum and the wavelength of the lines depend on the anode material d. The spectrum of the characteristic x-radiation is a line spectrum and the wavelength of the lines depend on the anode voltage

c. The spectrum of the characteristic x-radiation is a line spectrum and the wavelength of the lines depend on the anode material

Select the wrong statement a. The HU of water is 0 b. The Hounsfield scale is a relative scale related to the mass attenuation coefficient of water c. If the linear attenuation coefficient of a tissue is less than that of water it is negative d. The HU of bones is always positive

b. The Hounsfield scale is a relative scale related to the mass attenuation coefficient of water

The speed of propagation of ultrasound is greater in solids than in gases because... a. Solid bodies have much greater density b. Solid bodies have much less compressibility c. Solid bodies have much greater density and compressibility d. Gases have much less compressibility

b. Solid bodies have much less compressibility

Which organ/tissue has the smallest CT-value? a. Lung b. Liver c. Breast d. Bone

a. Lung

In which situation does the Doppler frequency shift achieve its highest value? a. When the flow direction and the ultrasound beam are parallel b. When the angle between the flow direction and the ultrasound beam is small c. When the angle between the flow direction and the ultrasound beam is large d. When the flow direction and the ultrasound beam is perpendicular

a. When the flow direction and the ultrasound beam are parallel

Which tissue or medium can be found in the negative range of the Hounsfield scale? a. Bones b. Soft tissues c. Lungs d. Water

c. Lungs

Which statement is false considering the resolution of the ultrasound equipment? a. The axial resolving limit is characteristically smaller than the lateral one b. The axial resolving limit is the smaller, the shorter is the length of the pulse c. The lateral resolving limit is the greater, the larger is the beam width d. The lateral resolving power is always bigger than the axial one

d. The lateral resolving power is always bigger than the axial one

An ultrasound diagnostic device has a 3.5 and a 5 MHz transducer. Which of them has greater resolution? a. The one with 3.5 MHz b. The one with 5 MHz c. Their ranges are equal d. Range depends on acoustic impedance

b. The one with 5 MHz | higher frequency = higher resolution but lesser depth

In which technique is windowing used? a. CT b. SPECT c. PET d. MRI

a. CT

What electromagnetic radiation is used in Magnetic Resonance Imaging? a. Infrared b. Visible light c. Radio waves d. UV

c. Radio waves

Is it possible (at least theoretically) to detect the distribution of two isotopes simultaneously in the body with SPECT? a. Yes, it is b. No, it is not since the isotope radiates only one photon c. Only with SPECT-CT d. Only with two SPECT cameras

a. Yes, it is (but NOT possible with PET)

Myocardial perfusion scintigraphy a. ... informs on the lumen of coronary arteries b. ... applies TC-99m pertechnetate as radiopharmaceutical c. ... is a method to diagnose ischemic heart disease d. ... has low prognostic value

c. ... is a method to diagnose ischemic heart disease

Consider the pulse rate distribution curve recorded by the scintillation counter, which is the odd man out? a. Photo peak b. Noise region c. Pair production region d. Compton region

c. Pair production region

Bone scintigraphy a. Has though it is specific, a low sensitivity b. Is usually carried out with a PET/CAT scan c. Is based on the function of osteoblasts d. Is based on the function of osteoclasts

c. Is based on the function of osteoblasts

The A-image acquired in ultrasound diagnostics can be used to determine... a. ... the speed of motion of reflecting surfaces b. ...the speed of propagation of ultrasound c. ... the compressibility of reflecting surfaces d. ... the distance between reflecting surfaces

d. ... the distance between reflecting surfaces

In which of the following cases is the reflectance of ultrasound almost 100%? a. If the acoustic impedances of the two media differ significantly b. If the acoustic impedances of the two media differ only slightly c. Only if one of the media is air d. If the acoustic impedance of the coupling medium is equal to the geometric mean of the acoustic impedances of the previous and subsequent media

a. If the acoustic impedances of the two media differ significantly

Which of the following phenomena can be used to detect US? a. Direct piezoelectric effect b. Inverse piezoelectric effect c. Scintillation d. Wave superposition

a. Direct piezoelectric effect

What is the spatial limit of resolution of a medical PET? a. 30 micrometers b. 300 micrometers c. 3000 micrometers d. 30000 micrometers

c. 3000 micrometers (3-4 mm)

Windowing is used to process images produced by which imaging method? a. CAT-scan b. SPECT c. PET d. MRI

a. CAT-scan

Which statement is wrong? According to the doppler effect.. a. The frequency is decreasing when the observer is approaching the source b. The frequency is decreasing when the source is moving away from the observer c. The frequency of the reflected sound is increasing when the reflecting surface is approaching the source or rather to the detector d. The frequency is increasing when the source is approaching the observer

a. The frequency is decreasing when the observer is approaching the source

Which is not transfer function operation? a. Production of inverse (negative image) b. Windowing c. Gamma d. Fourier transformation

c. Gamma

What is the field of medical application of a Doppler Ultrasound device? a. Heat therapy b. Removal of dental deposits c. Diagnosis of thrombosis d. Fetal hearing detection

c. Diagnosis of thrombosis

What is the reason for pulse mode operation in ultrasound diagnostics? a. To separate the emitted pulse and the signal to be detected b. To minimize the radiation load to the physician c. To minimize the radiation load to the patient d. This is the only way to increase beam diameter

a. To separate the emitted pulse and the signal to be detected

If the frequency of ultrasound increases... a. Its reflectance decreases b. Its penetration depth decreases c. Its speed decreases d. Its specific clamping decreases

b. Its penetration depth decreases

How does a DSA device work? a. It digitizes the image b. It subtracts noise from the image c. It subtracts images taken before and after the administration of contrast agent d. It serves as a digital image display

c. It subtracts images taken before and after the administration of contrast agent

Which statement is false for the Doppler-effect? a. The frequency of the radiation decreases if the source approaches the observer b. The frequency of the radiation decreases if the source moves away from the observer c. The frequency of the reflected radiation increases if the reflecting surface moves towards the detector d. the observed frequency increases if the source of radiation moves towards the observer

a. The frequency of the radiation decreases if the source approaches the observer

What is the condition that makes a nucleus NMR active? a. It does not have unpaired electrons b. Low (preferably less than 20) atomic number c. Even number of both protons and neutrons d. Magnetic momentum

d. Magnetic momentum

Which method can be used in case of brain damage? a. CT b. SPECT c. PET d. MRI e. Angiography

d. MRI

Which is valid for the spectrum of the ultrasound pulse? a. It consists of one band b. It consists of several bands c. It consists of several lines d. It consists of one line

a. It consists of one band

The most widely used radiation type in radioisotope therapy (RIT) is... a. Alpha radiation b. Negative beta radiation c. Positive beta radiation d. Gamma radiation

b. Negative beta radiation

Which imaging method is the most sensitive (i.e. capable of detecting the least amount of molecules)? a. PET b. CAT-scan c. MRI d. Ultrasonography

a. PET

When will the reflectivity of the ultrasound be close to 100%? a. If the acoustic impedance of the coupling medium equals to the geometric mean of the acoustic impedances of the coupled media b. If the acoustic impedances of the two media are very different c. If and only if one of the two media is air d. If the acoustic impedance of the two media are very close to each other

b. If the acoustic impedances of the two media are very different

What is TRUE about the reflection of ultrasound? a. If there is no reflection in the body there can be no US diagnosis b. Reflection interferes with the contrast in US imaging and should be eliminated c. It depends only on the density of the media d. it depends only on the angle of incidence of the US beam

a. If there is no reflection in the body there can be no US diagnosis

Which statement about Bremsstrahlung is not correct? a. It has a line spectrum b. There is a cut-off wavelength in its spectrum c. The emitted power is proportional to the square of the accelerating voltage d. The emitted power is proportional to the anode current

a. It has a line spectrum

Which of the following statements is false regarding ultrasonographic images? a. The disadvantage of the A-image is that it can only be one-dimensional b. The advantage of A-image over one-dimensional B-image is better representation of reflectance change c. M-image is the temporal variation of the one-dimensional B-image d. The duplex image is nothing else than a two-dimensional B-image

d. The duplex image is nothing else than a two-dimensional B-image

What sort of isotope would you use for a PET examination? a. A gamma emitting isotope b. A negative beta emitting isotope c. A positive beta emitting isotope d. No isotope is necessary for PET examination

c. A positive beta emitting isotope

Which method does not detect a radiation originating from the body? a. Gamma camera b. CAT scan c. SPECT d. PET

b. CAT scan

Which of the following is not a positron emitting isotope? a. C-11 b. N-13 c. Tc-99m d. F-18

c. Tc-99m

In which method is gadolinium (Gd3+) complex compounds used as contrast agent? a. SPECT b. PET c. MRI d. Sonography

c. MRI

Select the wrong statement a. Bremsstrahlung has continuous spectrum b. The spectrum of Bremsstrahlung ends with a wavelength maximum c. Characteristic X-radiation has a line spectrum d. Characteristic X-radiation is usually accompanied by Bremsstrahlung

b. The spectrum of Bremsstrahlung ends with a wavelength maximum

Which of these are useful in the field of radiopharmacology? a. Tc-99 b. Gadolinium c. Boron-51 d. Carbon-14

a. Tc-99

Which alternative is the odd man out of the US imaging methods? a. M-mode b. TM-mode c. Two dimensional B.mode d. Time dependent 1 dimensional B mode

d. Time dependent 1 dimensional B mode

Which method can be used to eliminate background noise? a. The median filtration b. The regulation of contrast c. X-ray annihilation method d. Pair production

a. The median filtration

What is the resolution of a clinical SPECT device? a. 8-12 mm b. 1-2 mm c. 3-5 mm d. 3-5 cm

a. 8-12 mm

What can be examined with a Doppler-detector? a. The actuity of embryonal hearing b. The speed of blood flow c. The size of cerebral ventricles d. The abnormality of osteogenesis

b. The speed of blood flow

What can be the unit of acoustic impedance? a. dB/(cm*MHz) b. It is unit-less c. dB d. kg/(m2*s)

d. kg/(m2*s)

What is the unit of ultrasound reflectance? a. dB/(cm*MHz) b. dB c. It is unitless d. kg/(m2*s)

c. It is unitless

What is a voxel? a. The unit of precession b. The elementary volume in imaging c. The unit of magnetic moment d. The sequence number of a layer in a tomographic examination

b. The elementary volume in imaging

The I-131 sodium iodide ... a. ... is not accumulated by differentiated thyroid carcinoma b. ... is advantageous because of low patient radiation load c. ... is most often used for thyroid scintigraphy d. ... can be used to treat hyperthyroidism

d. ... can be used to treat hyperthyroidism

The F-18 fludeoxyglucose (FDG) ... a. ... emits only characteristic X-radiation b. ... is a tumor specific radiopharmaceutical c. ... 's gamma radiation is detected d. ... is used to examine glucose uptake by cells

d. ... is used to examine glucose uptake by cells

The image noise can be decreased.. a. ... by cooling of the detector applied for imaging b. ... by inverse Fourier transformation c. ... by increasing of the sampling frequency of the detector d. ... by gamma manipulation

b. ... by inverse Fourier transformation

In which of the following cases does the wavelength composition of X-radiation not change? a. If the anode current is changed b. If the anode material is changed c. If a filter is applied d. If the accelerating voltage is changed

a. If the anode current is changed

The diagnostic methods of nuclear medicine ... a. ... use only beta radiation b. ... use only positron radiation c. ... use both gamma and positron radiation d. ... use only gamma radiation

d. ... use only gamma radiation