W1

Question 1

List the steps in interpretation of medical imaging

Answer 1

1.Interpretation

Question 2

emphasizing the type of image and the orientation, limitations

Answer 2

1. X-ray techniques– X-ray attenuation to produce images (absorb & scatter x-ray beam different degrees). Produce shadows=image; ionizing radiation.
   - plain radiography–planar images, bone/chest, ionization

• mammography- breast tissue, high spatial resolution, ionization
• fluoroscopy-“live action” x-ray; visualize dynamic process i.e.. swallowing, can take spot images, video, rapid-sequence images; ionization
• angiography-fluroscopy, vessels inject contrast, DSA (digital subtraction angiography) subtracts bones and structures from images; ionization
• DEXA- (Dual-energy x-ray absorptiometry); quantitative determine bone mineral density=osteoporosis; ionization
• CT-computed tomography, CAT scan uses x-rays & computations to produce cross sect images throughout body; ionization

2. Ultrasound-
   - doppler–emits high-frquency sound & detects echoes from tissues; image by magnitude & delay echoes, sonar. NO ionization
   - fluid= dark, organ=gray, fat+air=bright
   - fetal, echocardiography, abd, pelvic, prostate, vascular
   - flow velocity in vessels, doppler shift by moving RBCs, waveform and color doppler images
3. MRI-magnetic resonance imaging; manipulate H+ in magnetic field produces cross sect images; NO ionization
   - many applications= musculoskeletal, CNS
4. Nuclear Medicine- radioactive agent in body, emits gamma ray imaged by gamma camera; planar, SPECT, SPECT?CT; ionization
   - show physiologic processes
   - ventilation/perfusion lungs, tagged WBC scan, octreoscan (find carinoid & tumors), bone scan

• PET/CT-positron emission tomography.
• images positron decay–higher resolution, usually combine with CT
• common agent=FDG; F-18 fluorodeoxyglucose
• goes to areas of high metabolism
• oncology, neurologic, cardiac applications
• ionization

Question 3

Describe the four basic densities that are visible on plain films

Answer 3

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Question 4

Describe how x-rays are produced and the role they play in image production in plain film radiography.

Answer 4

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Question 5

Define the terminology used to describe images: upright, supine, PA, AP

Answer 5

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Question 6

Explain how position of the patient can affect magnification, organ position, blood flow, and affect image interpretation

Answer 6

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Question 7

Discuss how the use of contrast agents can permit visualization of anatomic structures that are not normally seen

Answer 7

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Question 8

Describe how contrast agents can be administered

Answer 8

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