Why PA chest uses 72-inch SID

We shoot PA chests at 72 inches to keep the heart true-size and sharpen lung detail, but what’s the actual ESE change versus a 40-inch AP portable in your shop? I’m running 120 kVp with tight collimation to keep dose down and accuracy up, and would love real numbers if you’ve measured.

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At our place, 72" PA at 120 kVp with AEC averages about 0.12 mGy ESE; 40" AP portable at 100 kVp, no grid, runs about 0.18–0.22 mGy when SSD is about 35", so roughly 50–80% higher on the portables… Our ‘real numbers’ swing more with SSD and mattress height than SID alone; do you use a grid on the APs, or let SSD do the talking — physics is rude like that.

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I think those ESE readings really highlight how collimation and technique make a difference in dose management. It’s interesting to see how the 72" PA improves detail, particularly in heart size. Have you looked into how the AEC settings impact your readings? @karen_moreno84.

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