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From: Phil Hobbs on 17 Jan 2010 19:40 On 1/17/2010 6:37 AM, wc(a)wcarter.eu wrote: > On Jan 16, 9:05 pm, Phil Hobbs > <pcdhSpamMeSensel...(a)electrooptical.net> wrote: >> On 1/16/2010 5:31 AM, Androcles wrote: >> >>> "RichD"<r_delaney2...(a)yahoo.com> wrote in message >>> news:524e9de7-330d-40fd-90f5-0d671ec9ce7d(a)j19g2000yqk.googlegroups.com.... >>>> is it possible to design a subcutaneous x ray? >>>> A surgeon might want to see a depth just below >>>> where he intends to cut. >> >>>> The point is, I thought only bones are opaque to x rays. >> >>> The problem is focus. >>> Hold a page of text up at normal reading distance and focus on a few words. >>> Note that background and peripheral objects, although noticeable, are out of >>> focus. Now focus on a background object and note that the writing on the >>> paper is no longer in focus. All lenses, including those in your eyes, have >>> limited distances or ranges in which two objects on different planes (focal >>> planes) may be simultaneously in focus. >>> The solution has been MRI. >> >> There are lots of solutions to this. In optical microscopy, you can >> take images at several depths and combine them, choosing the level that >> shows the most contrast at each position. Zeiss has been selling >> systems like that for years. >> >> In confocal microscopy(*), you can just sum the images taken from >> different depths, since out-of-focus planes hardly contribute to the >> image at all. >> >> There's also phase-coded imaging, which uses an artistically designed >> phase plate to allow 3D reconstruction from a single image. (It's >> really a beautiful technique, which I'd like to understand better than I >> do.) >> >> So the old classical optics limitations are being overcome all over the >> place. >> >> Cheers >> >> Phil Hobbs >> >> (*)My thesis was on a phase sensitive laser scanning confocal >> microscope, and I helped invent the modern real-time confocal. >> >> -- >> Dr Philip C D Hobbs >> Principal >> ElectroOptical Innovations >> 55 Orchard Rd >> Briarcliff Manor NY 10510 >> 845-480-2058 >> >> email: hobbs at electrooptical dot nethttp://electrooptical.net > > Dr. Hobbs; > > Can you tell me if "phase-coded imaging" is the same as "single lens 3- > D"? > If so, then that is something which I came up with in the 60's, and > patented in the 80's. Such an image may be phase-coded, time-coded, > frequency-coded, or encoded in any way which will allow some > differentiation at some sensor. It's a single-lens 3D technique that uses a computer generated phase plate. I haven't gone through the math, but I assume it uses the very large amount of redundant phase data in your average image in a more intelligent way. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 email: hobbs at electrooptical dot net http://electrooptical.net
From: RichD on 18 Jan 2010 20:21 On Jan 15, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > > is it possible to design a subcutaneous x ray? > > A surgeon might want to see a depth just below > > where he intends to cut. > > > The point is, I thought only bones are opaque to x rays. > > And you think an x-ray is going to let you differentiate > between the various types of soft tissue? ? The reason I ask, I read a profile of Nathan Myrvold's outfit, sort of an idea lab. They were brainstorming with some doctors, a surgeon requested a x-ray scanner, which could image subcutaneously. The physics team replied "No problemo!" I thought, huh? It's not a matter of focus, it's a matter of transmission/reflection. So I thought I'd present the question to this forum. http://www.newyorker.com/reporting/2008/05/12/080512fa_fact_gladwell -- Rich
From: Javi on 18 Jan 2010 20:50 RichD wrote: > On Jan 15, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: >> > is it possible to design a subcutaneous x ray? >> > A surgeon might want to see a depth just below >> > where he intends to cut. >> >> > The point is, I thought only bones are opaque to x rays. >> >> And you think an x-ray is going to let you differentiate >> between the various types of soft tissue? > > ? > > The reason I ask, I read a profile of Nathan > Myrvold's outfit, sort of an idea lab. They > were brainstorming with some doctors, a > surgeon requested a x-ray scanner, which > could image subcutaneously. The physics > team replied "No problemo!" > > I thought, huh? It's not a matter of focus, it's > a matter of transmission/reflection. It's a more practical problem. Focus isn't a problem, nor transmission/reflection either. In principle, if you make a tangential radiography, you may get what you want. It'd be something similar to a mamography. The problem is that you want the image on the fly. This means that you can't use any film: they need processing. So you have to rely on detectors. Amorph sylicon detectors are usually used for imaging during radiotherapy, but they have low resolution (and you need at least tenths of mm) and sensitivity (and you need to discriminate soft tissue from soft tissue). There is a no less important problem. If I understand what you want, the surgeon would be working at the same time that images are taken. That means that the surgeons and nurses would receive a significant amount of radiation. > > So I thought I'd present the question to this forum. > > http://www.newyorker.com/reporting/2008/05/12/080512fa_fact_gladwell > > -- > Rich
From: JosephKK on 20 Jan 2010 00:54 On Sun, 17 Jan 2010 09:24:36 -0500, jmfbahciv <jmfbahciv(a)aol> wrote: >Androcles wrote: >> "Michael A. Terrell" <mike.terrell(a)earthlink.net> wrote in message >> news:4B5266A5.C29D3EF6(a)earthlink.net... >>> Androcles wrote: >>>> I was fully conscious, just in agony. Doc asked me if it was the worst >>>> pain I'd ever experienced.... I said no, I had a shattered ankle with >>>> bone >>>> protruding in 2002 and a nurse immobilised it, but it came a close >>>> second. >>> >>> I sat through almost three full hours of Oral Surgery without any >>> painkiller, while in the US Army. The surgeon wanted to know how I kept >>> from passing out. >>> >> Eventually the morphine put me to sleep, but I don't believe it does >> anything for real pain. >> >It depends on the pain source. Morphine works for some things; other >kinds of drugs work for other kinds of pain. Talk with a hospice >nurse if you're really curious. > >/BAH S&*(, damn, f&(*! If i had my brain in gear properly once, i would have known that without having to be told. I do know enough about various pain / pain blocking brain receptors to have seen it. Metaphorically smacks self on forehead. I just hate having "Damn, that is so obvious" moments.
From: osr on 20 Jan 2010 09:44
I just had dental xrays for the first time in years (couldn't afford it, other medical bills) Nice low energy CCD imaging system. Fantastic images right into a PC with USB. I was so stunned I forgot to ask the resolution.and bit depth. Looked better then the old film, had more contrast. Since the sensor is in the mouth, maybe 1 inch long, a 3/4" wide, and 1/8" thick, how did they make the readout electronics for the CCD so it didn't latch up? Steve |