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Rd Im. 2

Ch. 18-23, 25, 26

QuestionAnswer
The basic photometric unit is the lumen
A digital display monitor is best viewed straight on
A liquid crystal is a material in a state between a liquid and a solid
Almost all digital images in medical imaging are viewed and interpreted on a digital display device
Medical flat panel display devices are _______ liquid crystal displays. monochrome
Medical flat panel display devices are identified by the number of pixels; active matrix
Compared to CRT's, AMLCD's have better _____ and less intrinsic _______ contrast; noise
The ambient light at a digital image workstation should be near darkness
Preprocessing the digital image is done ____ and post processing is done ____. automatically; manually
Flatfielding is accomplished through automatic calibration images called ____ and ____ images. offset; gain
Reregistering an image to correct for patient motion is done with pixel shift
Signal interpolation is performed during preprocessing
The national standard for image transmission in teleradiology is the DI COM format
Image field size is determined by matrix size and gray scale
A screen film radiographic artifact is any irregularity on an image that is not caused by the proper imaging or tissue by primary xray beam
A foreign object is an example of exposure artifacts
A guide-shoe mark is a processor artifact
The largest number of repeats is generally caused by exposure artifacts
Misalignment of the processor turnaround assembly can cause guide shoe marks
Thin lines on the leading or trailing edge of a film are guide shoe marks
Only patients can cause image blur
Kink marks are caused by bending the film
A quality assurance program monitors people
A quality control program is for all instrumental and equipment
The determination of how consistently radiologist's image interpretation match patients' ultimate diagnoses is called outcome analysis
A quality ___ program monitors people. assurance
What does JCAHO mean joint commission on accreditation of healthcare organization
Why do hospitals have quality control and quality assurance programs ensure quality patient care, receive payment, JCAHO approval
Most quality control testing on radiographic equipment is done annually
Filtration is measured with half value layer measurements
The collimator must be accurately aligned to within + or - 2% of the SID
The measure of kVp should be within + or - ___ of the kVp indicated on the console. 10%
A positive beam limitation (PBL) device in involved in collimation
A ghost image can occur in digital imaging because of incomplete erasure
_____ is done during preprocessing to correct for _____ over the image flatfielding; irregular patterns
___ is done during the imaging, flatfielding is done during the preprocessing, and lossless compression is done during post processing partitioning
CR cassettes can sit for a few _____ between exposures. days
Lossless compression reduces data files by a ratio of 10:1
Lossy compression reduces data by a ratio of 100:1
Computer aided diagnoses (CAD) requires the use of uncompressed images
Each anatomic part has an image ____ with a characteristic shape histogram
Medical images are transferred using the DI COM standard
Soft tissue radiography is unique because of the low subject contrast
When doing soft tissue radiography the differential absorption between muscle and fat must be enhanced
Breast tissue tends to be increasingly ___ in older women fatty
About ___ of breast cancer occurs in the ductal tissue 80%
The American Cancer Society recommends all women ___ years of age and above have an annual screening mammogram 50
The ACS recommends biannual screening for all women age 40 to 49 low risk
A dedicated mammography unit should have an automatic adjustable compression device
Every dedicated mammography unit is equipped with a low ratio grid
Breast compression has the advantage of lowering patient does, motion blur, and superimposition
Breast compression is used to lower patient dose and reduce focal spot blur
Cassettes used in mammography are designed with tighter film screen contrast
During fluoroscopy the xray tube is operated at less than 5 mA
The image intensifier improved fluoroscopy by increasing image brightness
Visual acuity in the eye is greater at the fovea centralis where cones are concentrated
The ability of the eye to detect differences in brightness levels vision is termed contrast perception
The rods in the retina are stimulated by ___ light; the cones are stimulated by _____ light. low; bright
Xray that exit the patient during fluoroscopy first interact with the input phospher
The input phosphor convert xrays to light; cesium iodide
The number of light photons emitted within the image intensifier is directly proportional to the amount of xray photons exiting the patient
Light produced at the output phosphor has been increased 50-75 times in intensity
The ratio of xrays incident on the input phosphor to light photons exiting the output phosphor is called flux gain
The ability of the image intensifier to increase the illumination level of the image is called the brightness gain
An image intensifier tube is identified by the diameter of the input phosphor
Fluoroscopy for an air contrast barium enema is generally done at 80 to 90 kVp
Viewing the fluoroscopy image in magnification mode increase contrast resolution, spatial resolution, and patient dose
Automatic brightness control (ABC) maintains the brightness of the image by varying kVp and mAs
Digital fluoroscopy uses at least 2 monitors
The time it takes to turn on the digital fluoroscopy xray tube and reach the selected mA and kVp is the interrogation time
The charged coupled devise used in digital fluoroscopy provides high spatial resolution, high signal to noise ratio, and high detective quantum efficiency
Digital fluoroscopy dose rate is lower than that for continuous analog fluoroscopy because the images are discrete, not continuous