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Rd Im. 2
Ch. 18-23, 25, 26
| Question | Answer |
|---|---|
| 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 |
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