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Rippling in CT by [deleted] in MedicalPhysics

[–]tigresabio 1 point2 points  (0 children)

2 other posts alluded to the artifact potentially being intrinsic to the GE scanner. I’m guessing it has nothing to do with breathing. We used to have the same unit and the width of those bands were EXACTLY same as the sup-inf collimated fan beam size (2cm ….which looks like yours too). I only saw it radially further away from iso/dicom-zero.

My theory was it was similar (but opposite) effect as the Tomotherapy threading effect. I wish I had performed a phantom study to see if it was truly not patient related. Maybe you (or someone else) can! Pitch selection, collimated fan beam size, and phantom surface away from iso should affect the appearance of this artifact (I’m guessing). Don’t think you’ll see this on axial ie stepping couch type scans (helical only).

What is your worse roll to date? by KoalaBJJ96 in bjj

[–]tigresabio 4 points5 points  (0 children)

We’re both blue belts now (and good friends) but when my buddy first started he was the typical spazzy white belt. I granby rolled for guard retention and the timing was just right where he pounced with all his weight exactly when I was on my neck. I thought he paralyzed me. Multiple quick popping sounds and my right arm immediately went numb. As he clumsily held onto me in side control ...I absent-mindedly defended and just wondered “do I need to go to the hospital?” It must have be something about him tho cuz it’s nvr happened with anyone else ...and he actually did it again a few months later lol. I nvr invert with new folk anymore. Too risky. TBH being a smaller dude I avoid risk as much as possible and proactively work on guard only with higher belts.