Talk:Fluorodeoxyglucose (18F)

Empirical formula

The formula is not correct (5 carbons only) 5 sep 2006

It's corrected now. --Ed (Edgar181) 20:01, 5 September 2006 (UTC)

Undiscussed move from fludeoxyglucose

It is customary to list pharmaceuticals on en.wiki under their USP monograph pharmaceutical names. The USP name of this pharmaceutical, commonly referred to as FDG, is fludeoxyglucose. See [1] for the monograph. Yes, there are other chemical names that are used more offen in the literature, but we do not use chemical names for drugs, or else for FDG we'd be using 2-deoxy-2-[¹⁸F]fluoro-D-glucose as the name of this substance. Similarly, we do not list Prozac under "Prozac" or under "(RS)-N-methyl-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propan-1-amine." Nor is there any discussion of which is more "accurate". Instead, we use the USP monograph pharmaceutical name, which is fluoxetine. You see the point? SBHarris 02:11, 15 August 2013 (UTC)

Wouldn't that be the INN, rather than USP, per Wikipedia:WikiProject_Pharmacology/Style_guide? The USP and INN might be the same, but for this international project the INN is named in the MOS and seems less localized. -- Scray (talk) 02:22, 15 August 2013 (UTC)

Moved back (restored), given above including clear guidance based on MOS. -- Scray (talk) 02:27, 15 August 2013 (UTC)

Right you are! I learn something new every day. In many cases they are the same but when they aren't, INN indeed rules (as I see from your MOS cite). So the Wikipedia page for APAP is paracetamol not acetaminophen. In the case of FDG, the name is almost the same for USAN vs INN, but not quite. The INN name is fludeoxyglucose (18F), which is the name previously used on WP, but USAN/FDA is fludeoxyglucose (F18). The 18 comes after the F, not before. The USP obviously uses the USAN name, so they have F18, not 18F. So you've got me. The page as you've restored it, is INN, and that is indeed per MOS guide. SBHarris 03:00, 15 August 2013 (UTC)

I moved the article per COMMONNAME.Specifically, "Wikipedia prefers the name that is most commonly used (as determined by its prevalence in reliable English-language sources)." If you doubt my point regarding "prevalence in reliable English-language sources", go to the PMC website and compare the number of results searching "fludeoxyglucose" and "fluorodeoxyglucose." You will find the latter search query produces over 30 times as many peer-reviewed articles. In light of this, I strongly recommend we ignore the pharmacology MOS and move the article to fluorodeoxyglucose. Bcary (talk) 05:18, 15 August 2013 (UTC)

It's not just WPPharm, it's also WP:MEDMOS that recommends the INN (though it says "generally"). I think those two wikiprojects should be invited to chime in here - it's not an obvious move, so it's worthy of discussion - I'll invite (neutrally). -- Scray (talk) 06:37, 15 August 2013 (UTC) ► Done. -- Scray (talk) 06:46, 15 August 2013 (UTC)

Since they are also listed above, I've invited WP:Chemicals and WP:Radiology as well. -- Scray (talk) 06:55, 15 August 2013 (UTC)

Break for Comments

Please comment (with above discussion as a reference) on whether this article should be named based on the INN (per WP:MEDMOS) or most commonly-used term (per WP:COMMONNAME). -- Scray (talk) 07:00, 15 August 2013 (UTC)

Another factor that might be considered is intelligibility: "fluoro-" will be more obviously fluorine than will "flu-" to most readers. Historical precedence seems to go to this paper (which b.t.w. should find its way into the article), which introduces the term as [¹⁸F]-2-deoxy-2-fluoro-D-glucose ([¹⁸F]-FDG) while published under the title: "The [¹⁸F]Fluorodeoxyglucose Method for the Measurement of Local Cerebral Glucose Utilization in Man". That said, as long as redirects are made and "also known as" represent the various forms, I cba'd which version is chosen. LeadSongDog come howl! 17:28, 15 August 2013 (UTC)

Another detail - I very much believe that you should subscript the mass number of the fluorine isotope since there is no particular reason not to, see also all the examples listed here http://en.wikipedia.org/wiki/Template:Diagnostic_radiopharmaceuticals. E.g. http://en.wikipedia.org/wiki/Fludeoxyglucose_%2818F%29. I.e. we'd have to add DISPLAYTITLE:Fludeoxyglucose(¹⁸F) [in double curly brackets] if I understand correctly. Macholl (talk) 19:01, 15 August 2013 (UTC)

You can do that for display purposes, as in the template pipelinks above, but superscripts are not permitted in WP page titles. If you mouseover them, you see what the page is really called.

As for the INN name vs. the common name, I really don't care that much, but wanted to see it discussed before precipitate action. There are a lot of pages on WP where we don't use the most common name, and others where we do. For example, we have an article called Heavy water when no chemist or professional calls it that. On the other hand, we don't have a Prozac article, even though that's the name everybody but physicians knows (of course it redirects, just as deuterium oxide does). We don't have a page called Dextrose even though we probably should (I'm going to create it soon, as it's not quite a synonym for D-glucose-- it can also be glucose hydrate). Fluorodeoxyglucose is a sort of unclear case where the INN chose a bad name, and would have done better (I'm reminded of the stupid temporary element symbols like Uuo for high Z elements like Element 118). We're trying to stay away from tradnames like Prozac, but fluorodeoxyglucose doesn't count there. That said, even if we do it, are we going to add an F18 or 18F to it? And put this in front or back of the name?

A tail behind, a trunk in front,

Complete the usual elephant.

The tail in front, the trunk behind,

Is what you very seldom find.

If you for specimens should hunt

with trunk behind and tail in front,

That hunt would occupy you long;

The force of habit is so strong.

-AE Housman

SBHarris 01:22, 16 August 2013 (UTC)

The name most commonly used by professionals is actually FDG, not fludeoxyglucose (18F), fludeoxyglucose (F18) or fluorodeoxyglucose. Of course FDG is an abbreviation and therefore unsuitable as a title. It probably doesn't matter which of the three alternative names are used; perhaps it is best to keep it simple and follow the INN. Axl ¤ [Talk] 10:02, 17 August 2013 (UTC)

Proposed move to 'fluorodeoxyglucose'

Although "fludeoxyglucose" is apparently the official name in the US, "fluoro-" seems to be by far the most common term - the first page of Google results turns up US governmental pages, such as PubMed, giving "fluoro-". I'd say that, for ease of looking-up, we should go with "fluorodeoxyglucose". hollyperidol 07:36, 4 September 2013 (UTC)

Cost of FDG for PET

In 2005 BTSI said "Most PET users can now purchase FDG for less than $300 per dose, and volume users can negotiate prices closer to $200 per dose. Comparatively, FDG was priced in the range of $600-$700 per dose not too long ago."[2] That is presumably just for the US. - Rod57 (talk) 12:21, 17 July 2014 (UTC)

There are more than two producers of FDG in the UK...

Avoidance of contact

"In practice, patients who have been injected with 18F-FDG are told to avoid the close vicinity of especially radiation-sensitive persons such as infants, children and pregnant women, for at least 12 hours (7 half-lives, or decay to 1/128th the initial radioactive dose)."

Is this really true? For example, ARPANSA (the Australian Radiation Protection and Nuclear Safety Agency) says that no avoidance of contact is required based on a conservative "close contact" dose calculation and dose limit of 1 mSv for the infant. Regarding breastfeeding they recommend a 1 hour interruption and say "During the period of interruption recommended in Table 8, the mother should regularly express and discard her milk. It should be explained that, if this advice is followed, the radiation dose will be no more than the infant would receive in six months from natural background radiation in Australia and that the radiation risk will be extremely small." See http://www.arpansa.gov.au/pubs/rps/rps14_2.pdf for more detail. — Preceding unsigned comment added by 137.219.45.154 (talk) 04:51, 10 November 2015 (UTC)

That whole paragraph is unsourced. It needs either to be supported by a valid secondary source, such as FDA-approved patient counselling material (Drugs.com claims to medically review such materials), so a Drugs.com article on f-18FDG shiould be a good secondary source. Luckily, a little Googling found "Fludeoxyglucose F 18", which says "Patient Counseling Information - Instruct patients in procedures that increase renal clearance of radioactivity.

Encourage patients to

- drink water or other fluids (as tolerated) in the 4 hours before their PET study.

- void as soon as the imaging study is completed and as often as possible thereafter for at least one hour."

That is the approved patient counselling for those patients who have received F-18FDG in the United States. Other nations' practices may vary, but that whole passage beginning "In practice, patients who have been injected with are told to... " isn't sourced in-line. That entire paragraph must be replaced with statements supported by valid secondary sources (such as Drugs.com) if no one comes forth with a good secondary source to support it. -loupgarous (talk) 01:28, 23 May 2020 (UTC)

Percentages don't add up in Mechanism of Action, Metabolic End Products, and Metabolic Rate section

In this passage,"Although in theory all 18F-FDG is metabolized as above with a radioactivity elimination half-life of 110 minutes (the same as that of fluorine-18), clinical studies have shown that the radioactivity of 18F-FDG partitions into two major fractions. About 75% of the fluorine-18 activity remains in tissues and is eliminated with a half-life of 110 minutes, presumably by decaying in place to O-18 to form 18O-glucose-6-phosphate, which is non-radioactive (this molecule can soon be metabolized to carbon dioxide and water, after nuclear transmutation of the fluorine to oxygen ceases to prevent metabolism). Another fraction of 18F-FDG, representing about 20% of the total fluorine-18 activity of an injection, is eliminated renally by two hours after a dose of 18F-FDG, with a rapid half-life of about 16 minutes (this portion makes the renal-collecting system and bladder prominent in a normal PET scan). This short biological half-life indicates that this 20% portion of the total fluorine-18 tracer activity is eliminated pharmacokinetically (through the renal system) much more quickly than the isotope itself can decay. The rapidity also suggests that some of this 18F is no longer attached to glucose, since low concentrations of glucose in the blood are retained by the normal kidney and not passed into the urine. Because of this rapidly excreted urine 18F, the urine of a patient undergoing a PET scan may therefore be especially radioactive for several hours after administration of the isotope.[10]

All radioactivity of 18F-FDG, both the 20% which is rapidly excreted in the first several hours of urine which is made after the exam, and the 80% which remains in the patient, decays with a half-life of 110 minutes (just under 2 hours). Thus, within 24 hours (13 half-lives after the injection), the radioactivity in the patient and in any initially voided urine which may have contaminated bedding or objects after the PET exam, will have decayed to 2−13 = 1/8192 of the initial radioactivity of the dose. In practice, patients who have been injected with 18F-FDG are told to avoid the close vicinity of especially radiation-sensitive persons such as infants, children and pregnant women, for at least 12 hours (7 half-lives, or decay to 1/128th the initial radioactive dose)", the article says 75% for how much is stored in cells, and then it changes its mind to 80%. What is going on, and which one should be kept? 80%, because it and the 20% that get excreted add up to 100%, right? Or is there something I am missing?RafChem (talk) 12:05, 23 April 2016 (UTC)

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