Imaging lecture 1 content

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Why do we care about imaging?

To know how to interact with them, when to refer out, and to explain images to PA.

What is radiology?

The branch of medicine concerned with radiant energy and radioactive substances, including x-rays, radioactive isotopes, ionizing radiation, and the application of this information to prevent diagnoses and treat disease.

Radiologist

Medical doctor

Radiographer

Radiology tech, in charge of positioning PA and taking image

When should you refer a PA for imaging?

expedite car without delay, outside the scope of practice, non-emergent/emergent

Ottawa rules

Used to determine if imaging is WARRENTED

American College of Radiology (ACR) appropriateness criteria

Used to determine what TYPE of imaging is appropriate

Meeting quadrule aim (sometimes 5)

Improved patient experience, better outcomes, reduced costs, improved clinician experience, health care equity

What is a radiograph?

The image that we see when looking at PA’s internal structures

Three components of a radiograph

X-ray beam source, a patient, image receptor

What is the risk of radiation/x-ray?

Can cause tissue damage

Safety with radiation

Occupational exposures, over-exposure, pregnancy, imaging modalities

Attenuation

Reduction in the number of x-ray photons in the x-ray beam as it passes through the human body

Different ways to capture x-rays

film/screen (standard), flouroscopy: dynamic/continuous real-time imaging, digital image production (CR & DR)

Radiodensity

physical quality of tissue (or object) that determines how much x-ray it absorbs

Radiolucent

Easily penetrated by x-ray, shows up black/dark gray on films. ex. air/fat

Radiopaque

Not easily penetrated by x-ray, shows up bright/white on films. ex. metal/bones

If an object has increasing radiodensity…

it will have decreased radiographic density

If an object has decreasing radiodensity…

it will have increased radiographic density

Arthrography

Looks at joints and surround soft tissue

Myelography

Looks at spinal cord, nerve root, and dura mater

Angle of projection

Form or shape of anatomical image depends on angle of projection of x-ray beam, this determines silhouette on film and alters radiographic density

What is the saying about one image being taken

“One view is no view'“

How man images should you take?

AT LEAST 2 at 90 degree angles from each other

Saggital axis

images anterior to posterior (vise versa)

Frontal axis

images left to right (vise verca)

Vertical axis

images superior to inferior (vice versa)

Routine exam

pos./neg. for suspected diagnosis, neg. for suspected diagnosis but suspected for different condition, inconclusive, wrong