Radiology Principles and Safety

X rays have high frequency and therefore a small wavelength absorbing x ray radiation can cause biological damage Ionizing radiation creates ions that damage a cell in an d a proportional amount Indirect damages cells permeates to DNA Trandtratdamage Radio sensitivity of rad amount radiation Damage DNA is the critical to radiation damage susceptibility of a cell of target relative Tdamagtforradiation w as low as acheivable ALAR A reasonably It accomplished by lowering time increasing distance and maximizing protection is Distance from the x Maximum MA exponential ray source reduces permissable dose selector effects It Kvp selector Scatter so radiation the effects reduces doubling exposure for us is quantity the 5,000 of an more scatter radiation 4 mr em image contrast the greater the body area exposed to the by 1 of x rays made contrast image distance the radiation is produced A grid is used to reduce machines Digital x ray worse spatial resolution scatter have better than Radiographic opacities most to least t For metal organs can be seen usually surrounded an x image is well dense soft tissue bone because but contrast convential more film opaquer fat air they are by fat ray where the animal aligned tissue 710cm thick on is lying on its so the caudal end is to the side the right Study Questions Radiology Lectures Dr. Daniel Monday August 28, 2023 1. How do the various types of electromagnetic radiation differ? X rays more dense more opaque Ct is opposite 2. What are the unique properties of x-rays? 3. What is the critical target resulting in cellular damage from radiation exposure? DNA 4. What determines tissues radiosensitivity? Exposure time area exposed 5. What is the difference between direct and indirect injuries by radiation? Direct affects the celldirectly indirect affects the water in neighbor cells whichpermeates into another cell 6. What are the three basic principles that can be used to reduce your radiation exposure when taking radiographs? Lower exposure time maximize distance from machine and wear as much protection possible 7. What is the maximum permissible annual total body dose limits of radiation for an occupational worker? 5 COO muem 8. What is the fundamental difference in the shadow created by an x-ray beam versus a shadow created by visible light? 9. What is the function/purpose of the following component of an x-ray tube • Cathode o Filament • Anode • Tube Housing 10. What are the components of the X-ray Control Panel and what do they do? KVP contrast mA Of rays Time exposure time mAs (if available) Focal Spot Size I area of rays per time image 11. What is the role of the collimator? Reduce scatter radiation 12. How does the collimator improve the image? provides slots for radiation to go 13. What is the role of the grid? Reduce scatter in tissue to cm thick 14. Which image would have been taken with a grid (A or B) O A B 15. How do traditional film screen systems create a radiographic Image? 16. What is the purpose of the developer and what is the purpose of the fixer? 17. At what point does the latent image become visible? 18. How does the LUT (look up table) influence the appearance of a digital image? 19. What are the 5 basic tissues densities seen on a radiograph? metal bone soft tissue fat fluid lair 20. The blue arrow is pointing to the right cranial lobar vein. What is its tissue opacity and why do we see it so distinctly? What is creating the tissue interface that allow you to see the ventral border of the liver (yellow arrow) It is the opacity of soft tissue we see it because it is surrounded by fat which is more opaque 21. The structure outline on the image on the left and above the arrow on the image on the right, is not an anatomic structure. What is the reason we see this opacity and what is it called? It is made by overlap of 2 tissues 22. Be able to identify 5 different subject opacities designated by the blue arrows on the radiograph. fluid soft tissue organ fat metal bone 23. The VD radiograph below is from the same animal as the lateral in question 5. Explain why the left humerus looks so unusual on the VD image but normal appearing on the lateral 24. The image on the left is a dog with pleural effusion and the image on the right is dog with no pleural effusion. Explain why the borders of the heart (arrow) are easily identified in the dog without pleural effusion. 25. The arrow is pointing to the (Left or right) femur? 26. Why is it important of have the area of interest centered in the x-ray beam?