Talk:PET-MRI

Attention (still) needed

I've started to tidy up this article, but it's still a bit of a mess. It reads more like a selection of snippets from sales brochures, rather than an encyclopaedic article. My time is rather limited, so I'm writing this here as a reminder to myself, or some pointers for anyone else who fancies having a go. These are still missing from the article, in no particular order:

• A discussion comparing sequential (Philips) to true simultaneous PET/MR
• Interactions between PET and MR systems
• Detectors: why classic photomultipliers don't work in a magnetic field, avalanche photodiodes, silicon photomultipliers
• Better localisation due to spiral path of positron in a magnetic field
• Typical construction: subject, RF coil, PET camera, rest of MR system
• More detail about strengths of MR, PET, and how combination may be used (e.g. co-registration of PET data onto MR data, MR data for attenuation correction)

GyroMagician (talk) 13:06, 5 January 2014 (UTC)

I've added a fair amount of editing and also some citations to the Citation Needed requests in the article. With that said, and as a question, I feel all new technology will sound like a "sales brochure" if the reader is unaware of the validity of the claims and prior to the common knowledge of the evidence. I'm not sure where to draw the line on my contributions from the perspective of the proof available as opposed to the discussion of the active ongoing research of this new technology. Leaving citation needed is a good warning flag, in my opinion, as I have now provided some to the previous entries I made. But then I would also suggest removal of items that are doubted should only be made with evidence (citation) to the contrary. But this is the beauty of WIKI and discussion. That is why I have added the citations I have and I hope it helps to keep the excitement of this obviously very new technology clearly on track, as mentioned in the multiple research publications I have linked. Even the FDA is excited about this technology, but the evidence is certainly not in yet (and it won't be for another decade at least), so I agree that the the sparkle of the references may leave some skeptical. If it is suggested or desired by anyone on this talk page, I will limit my input to statements that I can back up, going forward; regardless of what I know is occuring (IE., Ion therapy research). I am used to the products I work with taking many, many years prior to becoming commonplace or acceptance by the industry (and usually, even longer for insurance reimbursement :) ) along with tons of debate along the way. The debate usually leads to a much better overall public benefit and product, but it is a very, very slow method of spreading knowledge.

Although I didn't add them to the article I will simply respond (in order) to the above mention of missing information with my own information, as there is certainly a fair amount of discussion on these topics in the industry presently, and this can all be considered my opinion as opposed to fact by many people:

• Sequential vs Simultaneous - Sequential has always existed since the advent of imaging networks. Simultaneous advantages are incredible in the X,Y,Z and time correlations. Basically, 4 dimensional imaging improvements and motion correction considerations. Please reference this article, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2934593/ .
• Interactions - I'm not sure how to handle this request. Can some examples of the information desired or a more specific question be offered?
• Photomultiplier tubes - PMT's use typical "tube" technology, thus the electron beam stream is extremely susceptible to magnetic influence. Simply put, "tube" amplifers and technology can not operate within the magnetic fields used in MRI. APD's and SIPM's can be better explained by simple links to existing WIKI information. As far as MR/PET usage, APD's effectively operate as equivalent "tube" amplifier technology and are NOT susceptible to magnetic field influence. APD = Digital PMT, per se. SIPM's are basically "many" APD's on a single layer that improve control and resolution of the signal as well as provide timing resolution improvements (important in PET).
• All PET scanners suffer from a "tolerance" band for physical X,Y,Z isolation of the event due to timing limitations and the statistical reality that a positron travels in a random spherical direction following creation prior to annihilation. This reality effectively limits the resolution to 2mm regardless of how good the timing resolution is. Thus, PET image quality is more greatly influenced by the statistics (quantity) of events and accurate placement of the LOR, rather than the timing (physical improvement of X,Y,Z with <2mm resolution) of the event.
• For answer to construction I will provide the reference above again, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2934593/ , and state that the present MR/PET system offered by Siemens is an insert system that has sequential capability. The actual physical construction I will search for publically available references to link to in the future.

Kkadams115 (talk) 19:17, 16 January 2014 (UTC)

Move discussion in progress

There is a move discussion in progress on Talk:PET/CT which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 06:45, 7 January 2014 (UTC)

****OPPOSE**** MR/PET is NOT PET/CT, just as MR is not CT (if you want to use math to cancel the PET terms. ;) ). I encourage the talk for this page to be left on this page. I hope I have correctly understood the meaning of the "move" post here correctly. Kkadams115 (talk) 19:29, 16 January 2014 (UTC)