SP5:Image Presentation and Computers Flashcards
The type of computer memory that allows temporary storage
(a)ROM
(b) RAM
(c) Rad
(d) REM
(b) RAM refers to random access memory which is used for temporary data storage and is sometimes referred to as cache memory. ROM refers to read-only memory, and data stored there cannot be modified as easily as can data stored in RAM. A rad is the traditional unit for absorbed dose (an acronym for radiation absorbed dose), and REM is a sleep stage in which there is rapid eye movement.
A high-pass image filter removes:
(a)Relatively lower frequencies
(b) Relatively higher frequencies
(c) Frequencies that are both too high and too low
(d) Edges
(a) A high-pass filter allows high frequencies to pass through and reduces lower-frequency data from the resulting image. This can produce a noisier image with better edge definition.
Display devices in nuclear medicine include
(a)CRTs
(b) Video monitors
(c) Magnetic tape
(d) All of the above
(e) (a) and (b) only
(e) In addition to display on conventional film, nuclear medicine images can be displayed on CRTs and video monitors. Magnetic tape is a storage device rather than a display output.
Which part of the computer is used for data filtering?
(a)Buffer
(b) Array processor
(c) ROM
(d) ADC
(b) The array processor is used to perform filtering at high speeds. A buffer is a temporary storage area. ROM is read-only memory, and ADC is the abbreviation for analog-to-digital converter.
Which of the following is not true regarding data acquisition in frame mode?
(a)It requires much less memory than list mode.
(b) It has a higher acquisition rate compared to list mode.
(c) Data cannot be divided into different images at a later time.
(d) Incoming data are stored in a time sequence.
(d) Data acquisition in frame mode requires less memory and has a higher acquisition rate than list mode, but the data may not be divided into different images at a later time. List mode stores data in time sequence
Which is most useful for gated first-pass cardiac studies?
(a)List mode
(b)Frame mode
(a) List mode is most useful for gated first-pass studies because the data can be manipulated in many different ways to visualize anatomy and to generate time-activity curves. The disadvantage is that it requires more memory and has a lower acquisition rate than dose frame mode acquisition.
Static on film may result from:
(a)Removing a sheet of the film too quickly from the box or cassette
(b) Contact with skin
(c) Contact with dust and/or lint particles
(d) All of the above
(d) Static on film should be avoided as it may cause artifacts and can come from any of the situations listed.
Which type of filter is used exclusively with dynamic images?
(a)Spatial
(b) Temporal
(c) Band pass
(d) Low pass
(b) Filters are useful for smoothing images, especially when there are not many counts. Spatial filters are applied to static images, while temporal filters are applied to dynamic images. A low-pass filter reduces high spatial frequencies, and a band-pass filter removes both high and low spatial frequencies.
Assuming speed of retrieval is unimportant, which archiving option would be the best choice for a department with a limited budget?
(a)Magneto-optical disk
(b) Floppy disk
(c) Magnetic tape
(d) Hard disk
(c) Magnetic tape is a low-cost option for data storage, but the data retrieval time is significantly longer than optical disk, floppy disk, or hard drive storage.
If films appear too light, which of the following should be monitored?
(a)Chemicals are replenished at the correct rate.
(b) Developer temperature is set according to manufacturer’s recommendation
(c) Water does not overflow into the developer in the film processor
(d) All of the above.
(e) (a) and (b) only
(d) If developer is diluted, or not replenished as required, or if the temperature of the developer is incorrect, films may appear too light. All of the situations listed should be monitored.
Which of the following describes the fixing process?
(a)The undeveloped sodium iodide crystals are removed, and the developing process is stopped.
(b) Silver halide crystals become reduced to metallic silver.
(c) The undeveloped silver halide crystals are removed, and the developer is neutralized.
(d) None of the above.
(c) To develop film, the silver halide crystals in the emulsion that have been exposed to light during imaging are reduced to metallic silver. During fixing, those silver halide crystals that were not exposed to light are removed, and the silver metal is left behind. The developer is neutralized to stop the reducing activity.
Filtered back projection of SPECT data initially creates:
(a)Transaxial images
(b) Sagittal images
(c) Coronal images
(d) Oblique images
(a) Filtered back projection is an algorithm used to reconstruct the tomographic images following a SPECT study. Transaxial images are reconstructed first; these are then used to generate sagittal and coronal images. Unfiltered back projection often results in star artifacts.
Filtering of SPECT data may take place:
(a)Before reconstruction
(b) During reconstruction
(c) After reconstruction
(d) All of the above
(d) Filters may be applied before (preprocessing), during, or after (postprocessing) reconstruction. The filter that is most often used during reconstruction with filtered back projection is the modified ramp filter, also called the Butterworth filter.
Double emulsion film is used most often in nuclear medicine departments
(a)True
(b)False
(b) Single-emulsion film is used because only one side of the film is exposed to light.
If a technologist notices an unexpected hot spot on an image, he or she should:
(a)Take oblique or lateral views of the area.
(b) Attempt to remove the source of the signal by cleansing or removing clothing and reimaging, noting the difference for physician (pants removed, etc.).
(c) None of the above.
(d) (a) and (b)
(d) When there is a suspicious area on a film, whether hot or cold, the technologist is responsible for helping the radiologist determine the cause of the spot. This could involve cleansing the patient’s skin and/or removal of clothing followed by reimaging, as well as taking images at additional angles (oblique or lateral views). The technologist should not make any notations directly on the image.
