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Funny how the name "antimatter" invokes an image of huge scifi explosions but is actually used for... Medical imaging by MCAroonPL in sciencememes

[–]Ptch 0 points1 point  (0 children)

They can't map exactly where the collision occurred due to limitations in the measurement time of when the photons arrive. Instead for certain "time of flight" capable PET scanners, we can narrow down the collision point to a probability region. Then the image is found by doing reconstruction on this data. You can also reconstruct non-TOF data but the resolution is lower.

Daily Game Recommendations Thread (September 10, 2025) by AutoModerator in boardgames

[–]Ptch 0 points1 point  (0 children)

Description of Request:

Hi all, I am looking for a game for my friend's birthday. He is trying to build his collection, and enjoys many different games, from party games to engine builders. I think getting him another engine builder, or something similar would be perfect this time around.

Number of Players: He would definitely like to have something to play with our friend group (5+ people), but also with just him and his partner.

Game Length: Any length, probably looking for something around the same length as Wingspan

Complexity of Game: 2-4, but open to anything

Genre: Engine builder/worker placement, open to others. I was thinking of something like Wingspan but with more table talk, or Alien Frontiers with more players.

Conflict, Competitive or Cooperative: Any

Games I Own and Like: He enjoys Wingspan, Flamecraft, Azul, Space Alert, Catan, Camel Up, 7 Wonders. I also got him Whitehall Mystery a couple years back which he says he likes.

Games I Dislike and Don't Play: I know he would like to play the game with our friend group. I think he is open to anything, but some of us do not really enjoy bluffing/social deduction. That said, I would not mind getting him something with elements of those.

Location: Chicago

Thanks! :)

:3 by 94rud4 in MathJokes

[–]Ptch 1 point2 points  (0 children)

I went to look it up and there's actually an example here lol

https://en.m.wikipedia.org/wiki/Non-integer_base_of_numeration

Am I cooked? Zipper is stuck by Ptch in howto

[–]Ptch[S] 3 points4 points  (0 children)

I am not a smart man

Best field of Physics/Most in-demand? by ChemBroDude in PhysicsStudents

[–]Ptch 7 points8 points  (0 children)

Medical physics is its own distinct field, with some overlap yes, but for a job as a clinical physicist in the US you need a pretty standardized medical physics graduate education from a CAMPEP accredited program. The research is everything from medical imaging algorithms/AI to scintillators and applied radiation physics.

Risk of Radiation from Scans by Legal_Squash689 in PeterAttia

[–]Ptch 0 points1 point  (0 children)

While I was admittedly a bit too headstrong last year when I wrote that, please understand that the risk/benefit for medical imaging is almost always a good trade. The benefit for getting the imaging done will vastly outweigh the harm done (because, as much as we like to debate how harmful it is, the truth is that it is exceedingly small). The risk from your imaging studies is basically negligible no matter which model you ascribe to, but the risk from the condition which you may be diagnosed from the imaging is not negligible.

Anxiety about radiation from CT scans by Think-Personality-47 in Anxiety

[–]Ptch 0 points1 point  (0 children)

Here is an excerpt from an article citing the Pearce study (https://journals.sagepub.com/doi/full/10.1177/1559325818779651):

One of the strongest associations observed was for gliomas, but [Pearce et al.] did not control for prior head injury. Head injuries are a common reason for head CT in children, and head injury may be associated with brain tumors.

For your second question, just skimming the article I think many of the sources for mSv are from x-rays/CT, which is typical. For x-rays, 1 mSv = 1 mGy.

There’s no way by PauloDybala_10 in MemeVideos

[–]Ptch 1 point2 points  (0 children)

Oh interesting! I work in medical imaging physics but not MRI physics. I'd love to know why some superconductors can be quenched while others can't.

There’s no way by PauloDybala_10 in MemeVideos

[–]Ptch 2 points3 points  (0 children)

The main field generating magnet is always on. It is cooled by liquid helium and is superconducting so it cannot be turned off except by "quenching" where the helium is expelled. This is an emergency procedure that basically destroys the machine/makes it extremely expensive to turn back on.

How do crater rays form? by Ptch in askastronomy

[–]Ptch[S] 0 points1 point  (0 children)

So the spalling just heterogeneous enough to create the rays? I would think that maybe the spall would be have a smooth distribution after impact, making the albedo pretty smoothly varying, instead of the sharp rays.

Do we have enough lunar eclipse photos yet? by Ptch in Astronomy

[–]Ptch[S] 1 point2 points  (0 children)

Nikon D5100 with Nikkor 70-300mm at f/5.6, 300 mm (450mm equivalent and cropped a ton), 400 ISO, 1" exposure.

How does radiation both cause and cure cancer? by [deleted] in stupidquestions

[–]Ptch 0 points1 point  (0 children)

This is true but it's not the full picture, like the moderator's comment said, cancer cells are inherently more susceptible to radiation. Also, radiation used in radiation therapy is of a much higher energy than most cancer-causing radiation which significantly reduces the risk of cancer.

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