Physics and Instrumentation Flashcards
A beta-minus particle is the same as a
Electron
If a radionuclide that had a physical half life of one million years, and a biological half life of one second, the effective half life would be
Less than one second
Rest mass means that
The particle has no kinetic energy
Gamma rays originate in the
Atomic nuclei
A Curie is
3.7 x 10^10 disintegrations per second
What is the standard deviation of 40,000 counts
200
Take the Square root of 40,000
Pair production is always followed by
Pair annihilation
During the process of beta minus or decay
A neutron is converted into a proton, and an electron
The difference in mass is noted in isotopes of a specific element is attributed to varying numbers of
Neutrons
Alpha decay results in a new nuclide with a
Mass number reduced by four, and an atomic number reduced by two
The transition of Tc99m to Tc99 is considered to be
Isomeric
The time required for a source of radioactivity to lose 50% of its activity by decay is called
Physical half life
An alpha particle consist of
Two protons and two neutrons
The dose equivalent for occupational whole body exposure is commonly limited to 50 mSv. How many rem is this
5 rem
Radioactive decay is what kind of process
Random
In the photoelectric process, the incoming photon
Is completely absorbed
When converting 1824 to an exponential form, the answer would be
1.824 x 10^3
Rad is the same as
Radiation absorbed dose
Two atoms with the same mass number, but different atomic numbers are called
Isobars
Milli Ci is the same as
3.7 x 10^7 disintegrations per second
The minimum MeV photon energy required for pair production is
1.022
10 mCi is equal to how many becquerels
370 MBq
When converting 10^3 to an exponential form, the answer would be
1.0 x 10^3
In order to maintain nuclear stability, as atoms increase in complexity, the number of
Neutrons must increase at a faster rate than the number of photons
The relative mass of a gamma ray is
0
Pair annihilation interaction is a reaction between
Electrons and positrons
In gamma emission, the mass number changes by
0
Positron decay comes from the nucleus that is
Neutron poor
The production of light nuclei from a heavy nucleus is called
Fission
In beta- emission, the negatron comes from where in the nucleus
Neutron
When electron capture occurs
An orbital electron is captured and combined with a proton to form a neutron
The function of the neutrons in the nucleus is to
Determine nuclear stability
After three half lives, the percentage of the original activity of a sample remaining is what percent
12.5
The difference between x rays and gamma rays is
Gamma rays are produced in the nucleus of the atom
The function of the proton in the nucleus is to
Determine physical characteristics of atoms
The conversion of one element to another by radioactivity decay is called
Transmutation
When using a probe for counting studies such as a thyroid uptake test:
A single bore collimator is used
The exponential increase in number of electrons from cathode to anode occurs in the
Photomultiplier tube
In planar imaging, resolution and sensitivity are
Inversely related
The basic function of a photomultiplier tube is to convert
Light into an electrical pulse and amplify the pulse
To obtain an accurate reading, a survey meter must be
Calibrated
What type of survey meter is best for high levels of activity
Ionization
To achieve the highest resolution using a parallel hole collimator
The patient is placed as close to the collimator as possible
Which detector has the greatest sensitivity for detecting radiation
GM meter
Which statements are correct regarding different types and uses of SPECT filters
High pass filters such as Ramp filter erases blurring
Butterworth filter is a lower pass filter
Artifacts caused by a collimator can be confirmed by performing
An extrinsic uniformity flood followed by second extrinsic uniformity flood with the collimator rotated at 90 degrees from the original
Scintillation detectors are used to convert light into electric pulses (T/F)
True
In nuclear medicine, the ability of a system to accurately depict two separate events is called
Resolution
Typically, an increase in resolution results in
A decrease in sensitivity
What is the maximum activity for a counter-sample
1 micro curie of activity
Increasing the hole diameter of septa results in
Increased sensitivity
Material that is hygroscopic
Readily absorbs water
A pulse height analyzer is
Electronic circuitry with an upper-level discriminator and a lower-level discriminator
When using a probe or well counter, lower and upper-level pulse discrimination is achieved by
Using a window
The full width at half maximum (FWHM) is often used as a measure of
Energy resolution
A dose calibrator has a radionuclide selection for
Radionuclides that have specific ionization/activity
Which of the following quality control tests should be performed each day as the dose calibrator is used
Constancy
When using a source to calibrate a survey meter, it should
Measure within 20% of its calibrated activity
Why cant the thyroid probe be used for imaging purposes
It has a open bore collimator
The amount of light emitted by a Nal(TL) crystal depends upon the
Energy of the gamma-ray
Energy absorbed by the crystal
The “dead time” of a geiger tube refers to the time during which
No radiation is detected
Light flashes in the scintillation crystal are converted into measurable electronic pulses by the
Photomultiplier tube
How often must a dose calibrator constancy test be performed
daily
Extrinsic resolution is determined by
Intrinsic resolution
Collimator physical design
Collimator material construction
The energy of the gamma events
The center of rotation measurement
Determines the offset between the camera center and projections
In a Nal (TL) scintillation detector, the pre-amplifier is usually attached directly to the
Photomultiplier tube
Linearity testing of a dose calibrator must be performed
Quarterly
In a scintillation detector, Thallium is added to a sodium iodide crystal, to allow the crystal to
Fluoresce or give off visible light at a room temperature
The purpose of the photocathode of a photomultiplier tube is to absorb ______and emit ______
Photons
Electrons
In an ionization chamber the size of the pulse is
Directly related to the amount of energy deposited in the gas by the ionization event
Why is body contouring in SPECT imaging desirable
Increased resolution
When the same nonuniformity is back-projected at each of the angles of acquisition, the result is
A ring artifact
If insufficient voltage is applied to the electrodes of the ionization chamber
The ions created will recombine before reaching the electrodes
The most commonly used scintillation material in the nuclear medicine laboratory is
Nal (TL)
Pixel size should be
1/3 the size of the system resolution
The best collimator to use with modern gamma camera is
High resolution collimator
SPECT iterative reconstruction is a reconstruction process which
Reconstructs a SPECT image by the estimation of the distribution of counts through a series of successive approximations
Which detector provides a reading of the rate of radiation exposure
Ionization chamber
How often must a dose calibrator geometry test be performed?
On instillation or after repair
The device that operates in the saturation range includes all of the following
Ionization chamber
Dose calibrator
