RTE 1042 - ... (Unit 2-1)

Label

1. Eyelid

2. Pupil

3. Sclera

4. Iris

Label

1. Ciliary Muscle

2. Cornea

3. Iris

4. Lens

5. Aqueous Humour

6. Sclera

7. Medial Rectus Muscle

8. Lateral Rectus Muscle

9. Retina

10. Choroid

11. Macula

12. Optic Nerver

13. Vitreous Humour

What is the human eye anatomically designed to do?

• Gather light

• Focus light

• Convert it to nervous impulses

• Transmit it to the brain for processing

What is the purpose of the Aqueous Humour, Cornea, Iris, and Lens?

Gather and focus the light.

What do specialized cells of the retina do?

Convert the image to nervous impulses.

What does the optic nerve do?

Transmits the impulses to the brain for processing.

What does the rod and cone cells do?

Image Conversion

What part of the human eye contains photsensitive pigments?

Roda and Cone Cells

Threshold Detection

Visual phenomenon involving the perception of extremely small or faint details (resolution).

Boundary Effect

Difficulty visually perceiving subtle contrast differences that are distant from one another.

Veil Glare

Occurs when the intensely bright light from a viewing monitor floods the eye directly, reducing contrast perception and resolution.

Masking (Shuttering)

Used in post-processing to remove bright unexposed areas outside the collimated field that contribute to veil glare.

Is Masking to hide lack of collimation okay?

No

Industrial Radiography

Test the intergrity of castings, welds, etc.

Forensic Radiography

Evaluate counterfeit money, contents of packages, art forgery.

Art Restoration

Detect images under existing paint, composition of paint, brush styles.

Archeological Radiography

Mummified remains.

• Jewelry, disease, homicide, diet, ceramics.

The human eye is designed to gather light and convert it to _____________.

Nervous Impulses

The visual phenomenon involving the perception of fine details is termed:

Threshold Detection

Attenuation

Reduction in the total # of x-ray photons remaining in beam after passing through a given thickness of material.

Attenuation is the result of:

Photoelectric Absorption and Compton Scattering

__________ and ___________ of the photons must be increased with increased body part thickness.

Quality and Quantity

_____________ and high density attenuate greater % of the beam than ________________.

• Higher atomic #

• Lower atomic #

What produces less IR exposure because it attenuates the x-ray beam more?

Bone

• Calcium has a high atomic # and highest density

Rank Fat, Muscle, Bone, and Air in order from least attenuating to most attenuating:

• Air

• Fat

• Muscle

• Bone

Subject Density

Impact of patient tissue on IR exposure.

• Thicker/denser body parts absorb more radiation, produce less IR exposure

Subject Contrast

Degree of differential absorption.

What causes the degree of differential absorption in subject contrast?

• Different tissues in the patient’s body

• Atomic # and tissue thickness/density

• High subject contrast

• Low subject contrast

Subject Detail

Spatial Resolution

Size Disortion

Misrepresentation of size or shape of structure.

What can affect the overall thickness and composition of the patient’s tissues?

Pathology

Additive Condition

Disease causes the affect body tissue to increase in thickness, effective atomic #, and/or tissue density, there will be greater attentuation of the x-ray beam.

Destructive Condition

Disease causes the affected body tissue to decrease in thickness, effective atomic #, and/or tissue density = less attenutation of the x-ray beam.

When performing a PA chest on a patient with emphysema, using proper AED detector selection, the responsible radiographer would:

Allow the AEC system to a

Which of the following are addivkjdkfjsdjfklsjdflk

• Hydrocephalus

• Acromegaly

• Atelectasis

• Chronic Osteomyelitis