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CT test 1
| Question | Answer |
|---|---|
| average size of gantry opening | 70-90cm |
| computers that handle data composed of constantly varying electrical currents | Analog computers |
| analog computers operate on what qualities | continuous physical qualities (electrical signals, pressure, temperature) |
| computers that handle data composed of definite quantities of current | digital computers |
| what type of data do digital computers operate on | digital data |
| devices used to enter information into the computer for processing | input devices |
| examples of input devices | keyboard, track ball, mouse, camera, ct detectors, ultrasound transducers, mri coils |
| devices that display information generated on a computer | output devices |
| examples of output devices | crt screen, video monitors, graphic displays, printers, laser, film recording, voice output |
| process of saving information in digital form to an electronic medium for later display | data storage/ electronic archiving |
| T/F: only raw data not image data is stored | false; only image data is stored, not raw data |
| why are ct detectors curved | to match the angles of the x-ray beam |
| 3 types of storage devices | redundant array of inexpensive disks (RAID), magnetic, optical |
| if you half your slice thickness what happens to the number of slices | it doubles |
| examples of RAID devices | multiple hard drives working together as a single storage device; PACS archives |
| examples of magnetic storage devices | magnetic tape, magnetic disks |
| examples of optical storage devices | cd, cd-r, CD-ROM, dvd |
| environmental concerns for computers | temperature, humidity, cleanliness |
| a comprehensive information system dealing with all aspects of information processing in a hospital; focuses on administrative issues, patient demographics, financial data, etc. | hospital information system (HIS) |
| a computer system used to manipulate and distribute patient radiological data; stores radiology reports, scheduling of patients, etc . | Radiology information system (RIS) |
| an image that has been converted into numerical values for transmission or processing | digital image |
| an arrangement of columns and rows | matrix |
| a picture element | pixel |
| a volume element | voxel |
| pixel size determines what | spatial resolution |
| the smaller the pixel, the greater the what? | spatial resolution |
| formula to find pixel size | FOV in mm/ matrix |
| find the pixel size of 240mm FOV and 256x256 matrix | 240mm/256=0.94 |
| find the pixel size of 20cm FOV and 256x256 matrix | 200mm/256=0.78 mm |
| ability to represent small objects and diffrentiate between closely spaced objects | spatial resolution |
| how many mm in an inch | 25.4mm/ 1 in |
| how many mm in 1cm | 10mm/ 1cm |
| matrix size for nuclear medicine | 64x64 |
| matrix size for ultrasound | 512x512 |
| matrix size for fluoro | 1000x1000 |
| matrix size for digital radiography | 2000x2000 |
| matrix size for CT | 512x512 |
| matrix size for MRI | 256x256 |
| matrix size for mammography | 4000x4000 |
| processes related to handling multiple types of information | informatics |
| fundamental formula used in image reconstruction | fourier transformation |
| a set of rules for getting a specific output from a specific input | algorithm |
| process of filtering data | convolution |
| why is ct better than diagnostic imaging | removes tissue superimposition, improved contrast resolution, view tissues in multiple planes, can change tissue contrast scale |
| limitations of ct compared to diagnostic | high pt. dose, poor spatial resolution, artifacts |
| who developed the math of image reconstruction by back projection | allen macleod Cormack |
| who worked for emi on radar systems and computer technology, theorized x-ray beam passing through objects and getting reconstructing an image with computer measurements, shares nobel prize 1979 with Cormack | Godfrey hounsfield |
| when did hounsfield create the first emi scanner | 1971 |
| how long did the first ct object take to reconstruct | 9 days to scan, 2.5 hours of reconstruction |
| what did the first scanner image | brains |
| how long did it take to image the first brain lesion | 20 minutes |
| who invented the first whole body scanner and when | robert ledley, 1974 |
| process of obtaining information to create images | data acquisition |
| patient table is made of what | carbon graphite |
| components of the gantry | x-ray tube, filter, collimator, detector, generator |
| common FSS of x-ray tubes | .5 and 1 mm |
| 1st generation; single perpendicular beam into a detector | pencil beam |
| fan shaped beam; covers more anatomy and entire detector array | fan beam |
| beam is cone shaped so it can cover the entire array and more than one row of detectors | cone beam |
| what produces high voltage and transmits it to the x-ray tube | generator |
Created by:
jayciebest