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^^^^^^ WARM GREETINGS FROM ^^^^^^^^^^^^ :-) Ivan Suzman 49/39/36 [log in to unmask] :-) Portland, Maine land of lighthouses 33 deg. F :-) ******************************************************************** Hi, all....... I just want to say a public THANK YOU to J.R. Bruman, who over and over again answers straightforwardly and cleary a vast array of questions that emerge from our PIEN members about complex, scientifc names and scientific things that are not easy to understand. Keep up the GREAT job, J.R.! Ivan :-) On Mon, 4 Oct 1999 21:28:45 -0700 "J. R. Bruman" <[log in to unmask]> writes: >Terry Hopping wrote: >> >> Can anyone tell me what can be detected on a PET scan and of what >value it >> is ? > >PET is the acronym for Positron-Emission Tomography. "Tomography" is >the technique of forming a 3-dimensional picture of something without >having to destroy it, so it's especially useful to visualize the >inside >of something that is both complex and valuable, such as a living >brain. >The "3-dimensional" picture is usually presented as a series of >slices >or cross-sections, just as one would see if the object (say, a brain) >were actually sliced up like salami. Numerous tomography techniques, >such as CAT scan, MRI, MRS, SPECT, and PET, all use the same >mechanical >principle and differ only in the kind of signal that is recorded. In >the CAT scan, for example, the signal is just an x-ray like in your >dentist's office. The mechanical principle requires that the >recording >device rotates around each point of the object so it "sees" that >point >from all directions, and the process is repeated for every point in >the >object. >"Positron-Emission" means that a radioactive chemical, injected >beforehand, emits penetrating particles called positrons, that are >detected by the recording device mentioned above. The injected >chemical >used for research in Parkinson's Disease is one that acts on brain >cells >just like dopamine, except that the positrons tell how much there is >at >any one point. In this way, positron-emission tomography (PET) can >show >in 3 dimensions just how well the dopamine-related parts of the brain >are working, either in a PD patient or a healthy person. Furthermore, >PET can do this while the subject is performing a task, such as >tapping >a finger or walking on a treadmill, so the researchers can see just >which part of the brain is doing what, and the effects of PD. >There are tons of scientific reports about PET used for PD research, >many of which are reviewed in the PIE archives; happy hunting! >Cheers, >Joe >-- >J. R. Bruman (818) 789-3694 >3527 Cody Road >Sherman Oaks, CA 91403-5013