Tissue air ratio - (i) depends on SSD; (ii) does not depend on beam energy. PDD does not depend on - (i) depth; (ii) field size. For ortho-voltage X-ray, the reference depth dose i... Tissue air ratio - (i) depends on SSD; (ii) does not depend on beam energy. PDD does not depend on - (i) depth; (ii) field size. For ortho-voltage X-ray, the reference depth dose is at (i) d=0 cm; (ii) d=0.5 cm; (iii) d=10 cm. Radiation exposure varies with distance - (i) directly; (ii) indirectly; (iii) as inverse square.
Understand the Problem
The question is presenting multiple-choice statements regarding radiation exposure, tissue air ratio, and other related concepts in radiology. Each point is asking for confirmation or correction about how certain factors relate to radiation principles.
Answer
TAR depends on SSD, not on beam energy. PDD doesn't depend on field size. Ortho-voltage ref depth d=0.5 cm. Radiation varies as inverse square.
The answers are: Tissue air ratio depends on SSD and does not depend on beam energy. PDD does not depend on field size. For ortho-voltage X-ray, the reference depth dose is at d=0.5 cm. Radiation exposure varies as inverse square.
Answer for screen readers
The answers are: Tissue air ratio depends on SSD and does not depend on beam energy. PDD does not depend on field size. For ortho-voltage X-ray, the reference depth dose is at d=0.5 cm. Radiation exposure varies as inverse square.
More Information
TAR (Tissue Air Ratio) is used in radiotherapy to determine how much radiation is absorbed. PDD (Percentage Depth Dose) indicates how dose varies with depth.
Tips
A common mistake is assuming PDD isn’t affected by SSD or energy, but it actually is.
Sources
- Chapter 6: External Photon Beams: Physical Aspects - international.anl.gov
- CHAPTER 6. EXTERNAL PHOTON BEAMS: PHYSICAL ASPECTS - irsn.fr
AI-generated content may contain errors. Please verify critical information
