Guest guest Posted December 6, 2011 Report Share Posted December 6, 2011 Hey Terry: While I'm on chemotherapy, my oncologists prefer that Inot live alone. I was falling way too much the two prior years, but havebut had no falls since last December.I think you're right on the radioactive material takeup times for the scans.That which really interests me is what I got on July 1945, from the firstatomic bomb exploded 70 miles away from my village in New Mexico.After not feeling well most of this year, i've been feeling better this pastweek and hope I can help my USC Norris oncologists improve how things turn out.On top of everything else, I had a fender bender on the freeway last week,but even there things have been OK. The lady had insurance and thedamages were neglible. That's my 3rd accident in 50 years I lived inLos Angeles and Orange County, not including the dozen or so of hit andruns where the persons ran, apparently not owning insurance on the vehicle? To: ProstateCancerSupport Sent: Monday, December 5, 2011 11:31 PM Subject: Nuclear Bone Scan I’ve just had my fourth bone scan, which was clear this time – the last one had an area ‘suspicious for metastasis’ which was enough for the oncologist to accept it as definitive. But….knowing how inaccurate all scans are, and how busy they were at the hospital yesterday, a thought struck me and I thought I’d ask for some input. I have in the past had the injection of the nuclear material two hours before the scan. My understanding of the procedure was such that this was the optimum time for the take up of the material before the material started to decay as it has a short half life. Yesterday it was four hours before the scan started and four and a half hours by the time it finished. I don’t know what material was used, but if for example it was 99mTc-methylene diphosphonate (99mTc-MDP) which seems to be commonly used, is it likely that the scan’s accuracy might be affected by the additional two hours before the scan was done? All the best Prostate men need enlightening, not frightening Terry Herbert - diagnosed in 1996 and still going strong Read A Strange Place for unbiased information at http://www.yananow.net/StrangePlace/index.html Quote Link to comment Share on other sites More sharing options...
Guest guest Posted December 6, 2011 Report Share Posted December 6, 2011 Terry -- From here: http://www.world-nuclear.org/info/inf55.html " The radioisotope most widely used in medicine is technetium-99m, employed in some 80% of all nuclear medicine procedures - hence some 30 million per year, of which 6-7 million are in Europe, 15 million in North America, 6-8 million in Asia/Pacific (particularly Japan), and 0.5 million in other regions. It is an isotope of the artificially-produced element technetium and it has almost ideal characteristics for a nuclear medicine scan. These are: >>> It has a half-life of six hours which is long enough to examine metabolic processes yet short enough to minimise the radiation dose to the patient. <<< Technetium-99m decays by a process called " isomeric " ; which emits gamma rays and low energy electrons. Since there is no high-energy beta emission the radiation dose to the patient is low. The low energy gamma rays it emits easily escape the human body and are accurately detected by a gamma camera. Once again the radiation dose to the patient is minimised. The chemistry of technetium is so versatile it can form tracers by being incorporated into a range of biologically-active substances to ensure that it concentrates in the tissue or organ of interest. Its logistics also favour its use. Technetium generators, a lead pot enclosing a glass tube containing the radioisotope, are supplied to hospitals from the nuclear reactor where the isotopes are made. They contain molybdenum-99, with a half-life of 66 hours, which progressively decays to technetium-99. The Tc-99 is washed out of the lead pot by saline solution when it is required. After two weeks or less the generator is returned for recharging. " FWIW, I think that a four-hour wait, and a six-hour half-life, means that there was enough radiation coming off the technetium to give a good scan result. That's a wild-ass guess. I don't know if the radiologists use " correction factors " for the time between the removal of the Tc from its generator, and the time of the scan. > > I've just had my fourth bone scan, which was clear this time - the last one > had an area 'suspicious for metastasis' which was enough for the oncologist > to accept it as definitive. > > > > But..knowing how inaccurate all scans are, and how busy they were at the > hospital yesterday, a thought struck me and I thought I'd ask for some > input. > > > > I have in the past had the injection of the nuclear material two hours > before the scan. My understanding of the procedure was such that this was > the optimum time for the take up of the material before the material started > to decay as it has a short half life. Yesterday it was four hours before the > scan started and four and a half hours by the time it finished. > > > > I don't know what material was used, but if for example it was > 99mTc-methylene diphosphonate (99mTc-MDP) which seems to be commonly used, > is it likely that the scan's accuracy might be affected by the additional > two hours before the scan was done? > > > > > > All the best > > Prostate men need enlightening, not frightening > > Terry Herbert - diagnosed in 1996 and still going strong > > Read A Strange Place for unbiased information at > http://www.yananow.org/StrangePlace/index.html > <http://www.yananow.net/StrangePlace/index.html> > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted December 12, 2011 Report Share Posted December 12, 2011 No. I’ve just had my fourth bone scan, which was clear this time – the last one had an area ‘suspicious for metastasis’ which was enough for the oncologist to accept it as definitive. But….knowing how inaccurate all scans are, and how busy they were at the hospital yesterday, a thought struck me and I thought I’d ask for some input. I have in the past had the injection of the nuclear material two hours before the scan. My understanding of the procedure was such that this was the optimum time for the take up of the material before the material started to decay as it has a short half life. Yesterday it was four hours before the scan started and four and a half hours by the time it finished. I don’t know what material was used, but if for example it was 99mTc-methylene diphosphonate (99mTc-MDP) which seems to be commonly used, is it likely that the scan’s accuracy might be affected by the additional two hours before the scan was done? All the best Prostate men need enlightening, not frightening Terry Herbert - diagnosed in 1996 and still going strong Read A Strange Place for unbiased information at http://www.yananow.org/StrangePlace/index.html Quote Link to comment Share on other sites More sharing options...
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