Thread by @mmahesh1

#RSNA22 #RSNA2022 diaries:
Conversations between MP and IM (Imaging Modality)

IM: Hey doc, why do u guys insist on placing Aluminum (Al) or Copper (Cu) filters in front of my mouth?

MP: It is mainly to filter out some of the lower energy x-rays coming out of Ur mouth.
@RSNA
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MP: Lower energy x-rays only increases patient skin dose & do not contribute to the overall image quality. Hence, by placing certain thickness of filter materials, we shape x-ray beam coming out of Ur mouth.

IM: Well, then why do U use only Al or Cu, why not Pb?

@aapmHQ

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MP: Because Lead is used to stop all x-rays. In fact, Pb is used in collimator housing to shape the x-ray beam coming out of your mouth, so that it is within the desired region. On the other hand, Al or Cu is used to filter out lower energy x-rays, making beam harder.

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MP: In fact, regulations (US FDA) require that if you (Radiography or Fluoroscopy) are operated at 80 kV, Half-Value-Layer (HVL) should be at a minimum 2.9mm

IM: BTW, what is HVL? Why do I need so much filtration?

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MP: Buddy, I need to head out to @McCormick_Place - . Why don't U sign up for my office hour, happy to explain what HVL is all about when I return !

IM: Will do as u say doc. Have a good meeting & btw if u spend time in technical exhibit check all the newbies displayed there

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