instrumentation didactic test out

Given an adequate amount of photons being counted, how does the thickness of the Na(TI) crystal affect imaging spatial resolution?

Thinner the crystal, spatial resolution decreases

The ______ sorts out photons of different radionuclides with different photon energies and separates scattered photons from the useful ones

Pulse Height Analyzer

The dose calibrator control procedure performed to assess the device's ability to measure accurately a range of low to high activities is called ______?

Linearity

What is the purpose of the pulse height analyzer?

Selects only pulses that correspond to an acceptable range of energies

The ______ of a peak is the physical characteristic of a radionuclide

Energy

At a minimum, how often should Chi-square testing be performed on a well counter?

Quarterly

The _____ the bell-shaped curve of an energy spectrum the poorer the energy resolution

wider

What type of gamma camera bar phantom only requires one acquisition per gamma camera head per week?

Hine-Duley bar phantom

_________ is the quantitative expression of camera resolution

Point-spread function / Line spread function

The dose calibrator operates in which section of the Voltage Response curve?

Ionization

The relative variations in count densities between adjacent areas in the image of an object are called?

Contrast

How often should dose calibrator accuracy be performed?

Annually

Which of the following quality control procedures are required for proper functioning of the survey meter?

Constancy and calibration

Which of the following is a common test used to assess medical image display devices?

SMPTE

A technologist needs to assess the gamma camera's uniformity with the collimator. Which of the following will the technologist perform?

Extrinsic flood field

Crystal

converts photon energy into light

Photocathode

converts light into electrical energy

Dynode

Amplifies/multiplies the photon

Pre-amplifier

amplifies pulses produced in PMT

Amplifier

Final amplification and shaping the bell curve

Pulse Height Analyzer

Selects registered pulses for imaging

The dose calibrator quality control procedure testing a long-lived standard at each of the frequently used radionuclide settings is called _______?

constancy

Low-energy all-purpose

Tc-99m

Medium-energy all-purpose

In-111

High-energy all-purpose

I-131

What is the best collimator for Thyroid imaging?

Pinhole Collimator

_______ is defined as the largest variation in counts over the useful field of view

Integral uniformity

As hole diameter ______ photons at greater angles pass through the collimator without being absorbed

increases

You have one camera in your nuclear medicine department and the weight limit is 500. You have a patient who needs a STAT V/Q scan and he weighs 509 lbs. What is your next course of action?

Call the ordering physician and let them know you cannot scan the patient because they exceed the weight limit

Which filter removes 1/r blurring when reconstructing a SPECT data set using filtered backprojection?

Ramp

The effect of ______ is that some events are lost because they occur too soon after the preceding event, and therefore the count value we measure is not the true count value, but somewhat less than that

Dead time

Which of the following parameters must be specified for a SPECT acquisition?

Time per frame

Image matrix

Number of frames

How often should linearity of a dose calibrator be measured?

Quarterly

______ is the most common SPECT acquisition technique in which the camera is stationary during acquisition and does not acquire while rotating between frames

Step-and-shoot acquisition

What type of crystal is used in a nuclear medicine gamma camera?

NaI(TI)

Wipe testing to detect removable contamination in each area of use must be performed ________?

Weekly

Which of the following devices converts light into measurable electronic pulses?

Photomultiplier tube

Pre amplifier

According to the NRC, how often should uniformity floods be performed on a gamma camera?

Daily

If a detector has a FWHM of 68 and is calibrated with Cesium-137, what would the detector efficiency be?

10.3% ((FWHM/photopeak) x 100)

According to the NRC, survey meters must be calibrated _______ and following repairs

Annually

Which of the following is caused when the next pulse is received before the last pulse has returned to baseline?

Pulse pile up

What is the starting point for the linearity dose calibrator quality control test?

Highest activity used in the department

Spatial information is converted to frequency information by the mathematical process known as _______?

Fourier Transform

What should you do to prevent a crystal from cracking?

maintain a stable room temperature

______ imaging is a series of images taken sequentially, each set for a length of time

dynamic

If SPECT images have a significant start artifact when taken with a 360 degree rotation, 32 stops for 15s/stop and a 64 x 64 matrix, which parameter will you change to eliminate the start artifact?

increase the number of stops

FWHM is often used as a measure of _______?

resolution

What energies are included if a 20% symmetric window is used for the 364 keV photopeak of I-131?

328-400

Which of the following decreases hot spots appearing as a star shaped artifact caused by septal penetration on a gamma camera?

high energy collimator

How would you determine geometric calibration factors for a dose calibrator?

varying the volume and/or type of container with known activity source

How do we assess patient motion on a SPECT image?

Sinogram

Geometry is done on a dose calibrator (select all that apply)

at installation and after repair

Be able to known what is not a gas filled detector

scintillation camera detector

Most well couunters measure radioactivity by use of?

Sodium Iodide (NaI) Crystal

Full width half max is often used as a measure of

Resolution

___ is the relative difference in counts per pixels or intensity between two points in an image

Contrast

All of these are ionization events EXCEPT

Coherent Scatter