Worksheet: LAC Calculations
Step 1. Download and print this document.
Step 2. Complete each question, showing all of your work. Indicate your final answer to calculations by
circling your answer. This is practice for this weeks test. This is for completion points.
Step 3. Scan the completed document or take a picture that is clear enough to show all work and
answers. Save the scanned document or picture as a jpeg or pdf file, and title as follows: LAC
Worksheet_Full Name.
Step 4. Submit the document or document image in Canvas as an document to complete the
assignment.
1. A research institute obtained a bone block 6 cm thick and irradiated it with a 60 kev beam.
There were 600 photons incident on the block of bone, and 100 were transmitted. Calculate the
LAC to three decimal places.
2. The same research institute obtained a 6 cm container of fat, and irradiated it with the same 60
kev beam. There were 600 photons incident on the block of fat, and 400 were transmitted.
Calculate the LAC to three decimal places.
3. Given these two equal thicknesses of material, discuss the differences in the LAC, the meaning
of the differences, and what is causing the differences.
4. Compute the HVL thickness for both of the above.
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5. What percent of photons would be transmitted after the 5th HVL of any material?
6. What percent of photons would be transmitted after the 10th HVL of any material?
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