Screen Film Radiology

More documents

Recommendations

Info

INFLUENCE OF ENERGY (kV) kV High Low Low Loss of contrast Pale image Lack of photons going through Pale and loss of information High INFLUENCE OF ENERGY (kV) Patient dose Penetration Contrast Loss of contrast Dark image High contrast Dark image The choice of kV depends on the patient anatomy and the object to be imaged • Thick or dense part of the body: High kV, ex. Abdomen, pelvis - 80 to 100 kV • Small or flat parts of the body: Low kV, ex. Breast, hand - 30 to 50 kV Low kV High kV Then the necessary mAs is elected to produce the clinically useful image mAs 26
INFLUENCE OF FOCAL SPOT SIZE: PENUMBRA Dark Clear Dark Dark Gray Clear Penumbra Fine (small) focal spot Large focal spot Gray Dark Sharp projection from a fine focal spot Large focal spot is responsible for blurr, leading to inability to distinguish between small, close objects LOSS OF SPATIAL RESOLUTION INFLUENCE OF FOCAL SPOT SIZE: PENUMBRA SOD OID SID Increased SOD The blurr effect, or Penumbra, can be decreased by: • Increasing the Source to Object Distance • Placing the image receptor as close as possible to the patient Decreased OID 27
Page 1 and 2: Screen Film Radiology Mohammad Reza
Page 3 and 4: 2. Basic Geometric Principles v a/A
Page 5 and 6: 4. Screen Composition and Construct
Page 7 and 8: 4. Intensifying Screen Function and
Page 9 and 10: 4. Conversion Efficiency (CE) Total
Page 11 and 12: 4. Noise Effects of Changing CE vs.
Page 13 and 14: 5. Characteristics of Film v 1 or 2
Page 15 and 16: The Hurter and Driffield (H&D) Curv
Page 17 and 18: Sensitivity or Speed v Absolute spe
Page 19 and 20: 6. The Screen-Film System v Film em
Page 21 and 22: 8. Scattered Radiation in Projectio
Page 23 and 24: The Antiscatter Grid v ↑ GR →
Page 25: IMAGE QUALITY INFLUENCE OF ENERGY (
Page 29: INCREASING THE SIGNAL - CONTRAST AG

Screen Film Radiology

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?