Talk:Positron emission tomography

message: "they would be exactly opposite in their center of mass frame but the scanner has no way to know this".
This is unclear. Is it because of relativistic speeds?
If so, perhaps it should be mentioned. — Preceding unsigned comment added by 82.68.94.86 (talk) 08:31, 22 June 2014 (UTC)
thread_title: Unclear sentence

message: Are the scan times quoted for PET/CT machines correct? The machine I have experience of - it's a couple of years old - requires significantly longer - the CT part takes approximately 10 to 14 minutes for a H&N CT, the slow time mainly being a result of the fact that the CT is very much a low-grade CT scanner. I am not sure what other machines do, and obviously times are very much dependent on the protocol being used, area being imaged, etc., but (in my experience) the CT part takes significantly longer than 30 seconds. 
zebdee
Answer:  With todays multi-detector helical CT scans, the scan time is much faster.  We can do an "eyes to thighs" CT scan in less than a minute.
NucsDoc
:And one should add in the context of combined PET/CT that this is always the case, since these are always the newer scanners and have the latest CT features, which are always VERY fast. The 1-minute full CT scan is typical there. It's the PET part that takes 10 or 15 minutes a section and will be much harder to speed up with future tech (though of course it will happen). SBHarris 09:33, 4 November 2006 (UTC)
thread_title: Scan durations quoted for PET/CT machines

message: What are the percentages of false positives for PET scans?
Answer: PET is not specific, it merely tells you which areas of the body have faster metabolism than others. This means it picks up inflammation, infection and injuries as well as tumors.
For this reason, PET is only suitable for diagnosing tumors in conjunction with other tests. Its other main role is staging of tumors i.e. assessing the extent of a tumor that has already been found by other means.
For example, a CT scan of the chest finds a single nodule in one lung. The question is then, "is this cancer?". PET scanning in this situation can tell you whether this nodule is likely, or unlikely to be tumor.
There was a recent review of PET imaging in lung cancer. In the case of the solitary pulmonary nodule scenario, the specificity of a "positive" PET scan was 82%-94% depending on the precise PET technique used.
For staging of lung cancer - the most important role for PET is determining whether a lung tumor has spread to the center of the chest (the mediastinum).  However, even in this case there is a significant false positive rate (PPV : 74-93%; false positive rate: 44.6%). There is also a significant false-negative rate in this situation (up to 11.7%), so PET is usually used in conjuction with other tests, including exploratory surgery (mediastinoscopy). ChumpusRex 15:04, 5 March 2006 (UTC)
thread_title:  PET results 

message: PET Images are measured in different units like Bacqurel per mili litre, SUV (Standard Uptake Value), Percentage and  Counts/sec
What does each of these units mean?
Answer: Becquerel per mililitre is a measure of the concentration of radioactity within a region. One Bequerel is one count/sec.
The problem with this unit is that the value depends on how much radioactive tracer was given to the patient, the size of the patient, how much time has passed since the injection (due to radioactive decay), etc.
The SUV is a method for partially compensating for this. It corrects for the total amount of radioactivity given, and the approximate volume of the patient (volume is very difficult to measure, so it is estimated from weight).
SUV = \frac{Uptake\ (MBq / ml)\times Patient\ weight\ (kg)}{Administered\ activity\ (MBq)\times1000}
In words, the SUV is the uptake in the tissue divided by an estimate of the concentration in the body that was available to access the tissue.  Concentration is approximated as the injected activity divided by body weight.  The idea is to normalize the counts in the tissue to the counts that were available to be taken up by the tissue, or to "standardize" the uptake.   Markssss (talk) 04:52, 28 July 2010 (UTC)
thread_title:  Data units for PET Images 

message: I was just curious why there is a link to antimatter in the "See also" section. I couldn't see how the two were related, so I think there needs to be some mention of antimatter in the article if it relates, or the link should be deleted. cøøkiə Ξ (talk) 04:13, 22 September 2006 (UTC)
replies: text: Positrons are antimatter. This is clear if the wiki link to positron is followed. However, I see your point that it would be sensible to mention this in the article. ChumpusRex 12:14, 22 September 2006 (UTC)
thread_title: Antimatter?

message: I haven't seen anything in this page related to the reconstruction process, which is a very important component of PET, because of the low data quality of the process. Do you think that's worth including here? User:Sjayanthi November 3rd, 2006
:Absolutely, if you know something about it. If it's arcane, you can put it in its own section toward the end of the article, as something like "Image reconstruction techniques important to PET" and reference it higher in the section which first mentions how the scanner opperates in more general terms. Actually, there are many ways of doing this. The main article on PET scanning should probably not be too much longer, but long sections on ANY subtopic in PET scanning can be summarized in their own short sections, with a main article referenced there. Then, you can put in a lot more detail in that main article. This is how Wikipedia expands. The main rules here are: don't delete, improve! Next is BE BOLD in adding stuff. The worst that will happen if you know what you're talking about, (provided you don't hit a malicious delete-man), is that your section will be edited down, and the extra material offloaded to a subarticle. Don't worry too much about writing quality-- we need good information worst. Writing can be improved by secondary writers who have a lesser understanding of material. So go for it. SBHarris 09:14, 4 November 2006 (UTC)
thread_title:  PET Reconstruction 

message: I'm not much of an expert in these fields, being a year 9 science student, however in the article under the sub-heading 'How the scanner operates', it reads "the positron travels a few millimetres before encountering and annihilating with an electron."  Could somebody clarify for everybody (especially me) which material (the body or any other material) the electron is a part of?  Because I had always thought that an annihilation of a sub-atom in the body would result in the atom concerned becoming a positively charged ion, and causing disruption in the atomic structure of the organs being built from these atoms.  Thanks. 210.11.82.107 09:28, 19 November 2006 (UTC)
replies: text: Electrons wiped out by such positrons come from any old atom out there, and they do indeed become cations (positive ions) as a result. However, we're not talking about large numbers compared normal amounts of cations in the body (look at all those Na+,K+ and Mg++ floating around in all your fluids!). So it's no problem. If you calculate the number of moles of ions created from a normal PET scan in an hour, it's tiny-- something on the order of 10^12, which is a picomole compared with millimolar concentrations of your normal cations. Or 100 nanocoulombs with assocated currents of 50 picoamps, compared with microamps produced in your heart and brain.  Far, far worse damage comes from the gamma, which is ionizing also, but the damage is not caused by the ion per se (it's called that only because this is how these things were DETECTED originally), but rather from the high energy interactions which provide enough energy to break DNA. A simple ion contacting DNA won't do that. DNA is ionized (lots of negatives) and associates with positively ionized histones to be stored. Lots of ions in water are not bad, and in biology are normal. By the way, the atom the positron come from becomes a negative ion also, but this is soon fixed, as it picks up an H+ from solution and becomes a sugar hydroxyl. Again, no sweat, and generally no damage (due to the very small amounts of stuff made). SBHarris 08:47, 16 November 2006 (UTC)
thread_title:  Annihilation in body 

message: i just want to know about the line that says "the positron travels a few millimetres before encountering and annihilating with an electron."  but i thought that as soon as a positron encounters an electron, it annihilates...and electrons are present anywhere and everywhere.so how is that positrons are able to travel upto distances as large as milimeters inside the body...please somebody explain this...urgent ,specialy for me...i have a related project even...
:The distance any GIVEN particle travels in ANY material is related to its energy (all other things being equal), due to the fact the short wavelength particles, which of course are high energy particles, just "look" smaller, so have a smaller cross section. High energy electrons go a couple of mm in skin for radiotherapy, and Mev electrons up to several cm. A positron's no different. SBHarris 16:08, 28 March 2007 (UTC)
thread_title: Annihilation after some time?

message: Hello, in the lead paragraph it says PET produces images of "metabolic activity" or something along those lines a couple of times.  While this is the most popular use of PET, it is not necessarily the only use correct?  PET can be used to image any process providing you can make the right biomolecule into a positron emitter. It is true that FDG is by far the most widely used clinically, and it images metabolism, but theoretically PET can image anything.  Is this too specific for the lead paragraph? I understand the desire to state the most popular use, but as it is worded I think it is a bit deceiving. CallipygianSchoolGirl (talk) 02:27, 11 March 2008 (UTC)
thread_title:  Lead Paragraph Quibble

message: I notice that the illustration showing how the process works shows the Sun Microsystems brand name prominently, which bugs me. Would it be possible to redo this picture and remove this text and logo to make it generic and to remove the plug for the computer manufacturer? I'm sure Sun isn't the only one making this equipment. +ILike2BeAnonymous (talk) 20:51, 12 March 2008 (UTC)
replies: text: On the subject of bugs, I can't find Sun Microsystems mentioned anywhere in any of the illustrations; I did, however,  remove a reference to Siemens in a caption. - Neparis (talk) 03:19, 15 March 2008 (UTC)
thread_title:  Brand names in illustration 

message: This article duplicates and overlaps with the PET-CT article, with which it should be combined. Fbarw (talk) 20:09, 22 July 2008 (UTC)
thread_title:  Duplication 

message: I was under the impression that a PET scan analyzes the patient's entire body, to find areas where the uptake of the tracer indicates possible cancer.  A friend of mine has the impression that the scan is like an x-ray, in that it covers only a particular small segment of the body.  Perhaps both types of scans are used, depending on the circumstances?  I don't see the answer to this question in the article.  My guess was that, to the knowledgeable editors working on the article, the answer was so obvious that it didn't occur to anyone to spell it out! JamesMLane t c 04:30, 22 October 2008 (UTC)
replies: text:  The axial field of view (FOV) is the measure of what "length" of the body is being imaged at once in PET/CT, when you're doing just the PET part. That's about 8 inches right now, according to the literature http://jnumedmtg.snmjournals.org/cgi/content/meeting_abstract/48/MeetingAbstracts_2/46P-a. That means every 8 inches of your body must travel through the "ring" for a certain time, collecting gamma scientillations. I've been told (can't swear) that some of the newer scanners have 2 blocks of these 8 inch rings in a row, to give you more like 16 inches of height being counted at a time, so a "whole body" (they never count the body below the thighs-- nothing to see there usually) can be counted in just 3 sections. Usually a whole body PET does you from "eyes to thighs" that way, and takes 20 min to 40 min. The CT part is done in less than a minute and is over with, before you know it. It's the PET collection of radiation from the F-18 that takes all the time. And yes, usually if they'd bothered to get you into the machine and injected with isotope, they're not going to collect PET info for just a transverse slice 9 inches (or 18 inches) long!  They usually go for the whole body, which is pelvis to neck, or might also include head. SBHarris 01:28, 29 January 2009 (UTC)
replies: text: SBHarris, thanks for the detailed information.  Because you have a source you can cite, I hope you'll work that into the article. JamesMLane t c 19:47, 29 January 2009 (UTC)
thread_title:  Query -- scope of a PET scan? 

message: Under safety the article says that a PET scan is non-invasive. Yet the proecdure requires the injection of a radioactive substance on a biologically active molecule. Doesn't that make the procedure invasive?VR talk 16:54, 12 February 2010 (UTC)
thread_title: Safety

message: http://www.euronews.net/2011/11/23/x-rays-see-pain/  23/11/11 13:07 CET
Some highlights: Torsetn Gordh of Uppsala University,  Radioactive tracer mixed with D-Deprenyl, Rolf Jonsson (whiplash patient and chairman of Swedish Whiplash Society)
99.181.131.33 (talk) 23:57, 29 November 2011 (UTC)
thread_title:  Resource "seeing [[pain]]" 

message: There's a bunch of good stuff at fluorodeoxyglucose that could be merged here, including a cool animated 3-D PET scan of a human torso.
Gbuchana (talk) 18:42, 11 July 2012 (UTC)
replies: text: Don't suggest merges to long articles. This article is already long, and if we merge all that stuff in, we'd just be under the gun to summarize out the fludeoxyglucose stuff again to a subarticle, per WP:SS. If you think there's some good stuff in the FDG article that needs summary HERE, feel free to do it, per WP:SOFIXIT. The balance between where info should go, and to what level of detail in main and subarticles is always tricky and subject to debate, and nobody will object if you tastefully copy stuff, or summarize stuff to here. Just so long as you don't MOVE anything wholesale, so it disappears THERE and REAPPEARS here. That's always bad when your target article is long, and the stuff you pilfer from is shorter. For example, the image you mention was once part of this article, and somebody felt the need to MOVE it to the FDG article, thus leaving nothing HERE. See the problem? I'll go and copy it, and leave a copy there. BTW, I agree with your taste, and like that image so much that it's been on my userpage for years! SBHarris 20:19, 11 July 2012 (UTC)
thread_title:  fluorodeoxyglucose 

message: The current history section contradicts some facts, as apparently the first practical models were developed by Ter Pogossian and his team. From the NY Times obit: "Dr. Michel Mathew Ter-Pogossian, who led the research that turned the positron emission tomography (PET) scanner from an intriguing concept to a medical tool used in hospitals and laboratories everywhere... in the search for a workable model, great strides had been made by others over the decades, but it was Dr. Ter-Pogossian and his colleagues in St. Louis who produced a series of machines for commercial production and practical use in the 1970's... Early in his professional life, Dr. Ter-Pogossian built one of the first scanners to detect radioactivity concentrations in living material, as well as a tool for delivering radiation therapy for cancers of the cervix and uterus. In the early 1950's he recognized the potential of short-lived radioactive tracers, and he was one of the first to use them to find brain tumors and measure blood flow." http://www.nytimes.com/1996/06/21/us/michel-m-ter-pogossian-71-led-research-on-pet-scanner.html Thinkfood (talk) 07:21, 12 July 2012 (UTC)
thread_title:  History section missing Michel Ter Pogossian 

message: Can you add an image like http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/imgnuk/petscang.gif or http://www.whatisnuclearmedicine.com/upload/PET-SCAN-Brain.jpg ? It wasn't obvious to me that each detector can pick up activity within a cone, not a cylinder.  In other words, each tube detector can see the entire head, not just a single point in the head.  Otherwise it could only pick up events that occur in the very center of the circle, and I thought maybe the ring of detectors was translated around to scan other points in the head, or that there were multiple rings each focused on a different point, but now I see that's not how it works.  — Preceding unsigned comment added by 71.167.71.24 (talk) 15:53, 8 October 2012 (UTC)
thread_title:  Add an image for the direction of detection 

message: Maybe remove it or replace it with an appropriate alternate reference? 193.143.201.114 (talk) 06:51, 5 June 2013 (UTC)
replies: text: To clarify, this is the ref in the Operation subsection of Descriptions for the phrase which reads:"during which time it loses kinetic energy, until it decelerates to a point where it can interact with an electron."SBaker43 (talk) 23:32, 5 June 2013 (UTC)
thread_title: Ref 12 is a dead link

message: The following articles are proposed for merge;
* PET-CT
* PET/MRI
PET-CT has been proposed as a merge to this article for over a year, but this page hasn't been tagged. I have made this change and also propose that PET/MRI be merged here. This is because I believe the content would be better covered here, as the technology is very similar, as are the indications and outcomes. I think that coverage on this one page would improve the quality of the intended content of all three articles. LT90001 (talk) 09:30, 30 August 2013 (UTC)
thread_title:  Proposed merge 

message: Can someone please help fix? Thanks! Deluxegourmet (talk) 02:24, 25 March 2014 (UTC)
replies: text: Fixed. If you see how I did that, you can do it yourself next time. You just name the reference something with a  tag, with full reference as usual and  tag. Then, when you need to refer to the same reference again, you put in the front tag and no reference body, and add the end </ref> tag. You can put in the full reference name and tag anywhere in the article, as long as it's once and no more. The other tags are as described. SBHarris 03:31, 25 March 2014 (UTC)
thread_title: Refs 22 & 39 are identical

message: Cost per scan gives a figure of $1,100 for a PET scan which is woefully low and very misleading despite being properly sourced to a Cancer Care Ontario publication. I think this figure may be the cost to the government itself.  In the U.S., I have seen many PET scan bills from multiple hospitals with several insurance co.'s as well as a few for individuals without insurance.  The lowest by far was $2,000 for a bill with a 50% discount.  However, this is an outlier and the cost typically is $4,000 to $6,000 to the insurance co.  Unfortunately, my data falls under the heading of original research.  Regardless, something needs to be done to not seriously mislead the reader as to the cost.TL36 (talk) 02:56, 2 April 2014 (UTC)
replies: text: I think you guys are confusing the issue. The markup you Americans choose to pay doesn't affect the cost to the provider. Mine was free as in no money or insurance required, scarcely a useful datapoint. Greglocock (talk) 08:17, 23 May 2015 (UTC)
thread_title:  Cost per scan 

message: I guess this is purely subjective, but to me, the images of equipment standing empty lack visual interest. I think we should have a picture showing a human being, especially near the top of the article. I would suggest replacing the first one with this image, which shows a patient receiving care: http://en.wikipedia.org/wiki/File:PET_scan_image3699-PH.jpg --76.169.116.244 (talk) 20:21, 21 January 2015 (UTC)
thread_title: better image

message: It's my understanding that the desire to extend the CAT scan to puppies, gerbils, parrotsindeed the entire menagerie of domesticated animal companionsis what led to development of the more general PET scan. I'm puzzled that this isn't mentioned in the article. EEng (talk) 23:31, 29 December 2015 (UTC)
replies: text: Tough crowd. EEng 03:51, 5 February 2016 (UTC)
thread_title:  Relationship to CAT scan 

message: Moving this here as it is unsourced, per WP:VERIFY:
;Research
There are ongoing studies into using potassium 40 as this decays with a positron channel if an inexpensive way could be found to enrich the isotope into a pure form in order to scan human neural pathways for studying neurodegenerative diseases such as Alzheimers disease. The technology is based on new advances in sensing radiation combined with advanced reconstruction algorithms running on a single board teraflop system.
-- Jytdog (talk) 19:47, 6 April 2016 (UTC)
thread_title:  unsourced 1 

message: The Merriam-Webster dictionary says it should be hyphenated.--Leptictidium (mt) 12:42, 8 August 2019 (UTC)
thread_title:  Hyphen 

message: Hi, I made few changes as follows: 
1. Added a new para on PET for muscles. 
2. Divided the section "Musculoskeletal imaging" into two parts: (1) PET for muscles, and (2) PET for bones. 
3. Thinking of separating paragraphs for pharmacokinetics and pharmacodynamics paragraphs. I am now trying to re-write the whole article in simple words to be understandable by non-technical audiences. Also, I feel that text related to SPECT should be removed. There should be separate pages on PET-CT, PET-MR, etc.. 
Senior editors, please keep an eye. Thank you Earthianyogi (talk) 14:30, 20 April 2020 (UTC)
thread_title:  REWRITING 

message: Dear All, . I have noticed your valuable contribution on this Positron emission tomography  article/page. This Positron emission tomography  page has reached 108,412 bytes and I have more to write. I propose that section 'Bones' within the article Positron Emission Tomography be split into a separate page called PET for Bone Imaging. The content of the current page seems off-topic and these sections are large enough to make their own page. The page can be accessed here. 
Thank you Earthianyogi (talk) 00:06, 26 April 2020 (UTC)
thread_title: SPLIT : New Page for Musculoskeletal Imaging using [18F]NaF PET