Bill Posted March 2, 2006 Share Posted March 2, 2006 A question for those of you that have had more than one PET / CT scan or PET scan and have copies of the films in your possession. If you look on the far right edge of the film sheet there is an SUV setting #. It appears that this setting # is selected by the rad tech at the time he or she prints a copy of the films for the patient to take home. Are your SUV setting #s different from one scan to the next ? If so, have you noticed whether that setting # difference seems to make the images on the sheet darker, lighter or no change ? Thanks. B Quote Link to comment Share on other sites More sharing options...
john Posted March 3, 2006 Share Posted March 3, 2006 The SUV is the uptake number. I am guessing that as the numbers goe up the spots will become brighter. As they go down they will be darker. Just a guess. You probably know this but the SUV only applies to the PET Quote Link to comment Share on other sites More sharing options...
Bill Posted March 3, 2006 Author Share Posted March 3, 2006 John >>> I am guessing that as the numbers goe up the spots will become brighter. As they go down they will be darker. Just a guess. John : Thanks for the educated guess. This is my thinking also. My wife had a PET / CT today. The SUV scale was set at 4.80 on the copy printed for us. Last Oct. ' 05 was her first PET / CT. The SUV scale was set at 5.85 on that printing. Today's body images on the film sheet appear to be overall darker compared to the Oct. film. The bad news to report is that this darker imagery is revealing numerous small to moderately sized spots in her lung fields, ribs, spine and pelvis ( varying degrees of black ). These were all previous problem areas that Tarveca resolved. If my fears are realized, this rad report will be loaded with bad news. Her med onc appt. has been moved up to next Tues. in anticipation of this. Rad report should be finalized and faxed by Monday. If not, her med onc will request a prelim report or wet read. This is very discouraging and, as with so many others, the changes are dramatic and so sudden. B Quote Link to comment Share on other sites More sharing options...
cindi o'h Posted March 3, 2006 Share Posted March 3, 2006 Bill, I am going to throw in a guess on the reason for the differing #'s correlating a "setting". Each time I have one taken, the tech takes blood and does a blood glucose test and checks my height and weight. I think I can remember asking them a long time ago, the reason. And I believe it was to formulate the settings on the machine. Cindi o'h Quote Link to comment Share on other sites More sharing options...
J.C. Posted March 3, 2006 Share Posted March 3, 2006 The Standard Uptake Value shows the difference between a cold or hot cancer, but it is still only a prediction on how a cancer could evoluate without treatment. So the answer to it could be in the treatment following and the difference in SUV from one time to the next one could tell if the treatment done worked or did not work. Just my guess about it. Jackie Quote Link to comment Share on other sites More sharing options...
Bill Posted March 3, 2006 Author Share Posted March 3, 2006 Thank you for the additional replies. What makes my question particularly puzzling is that the PET / CT tech himself can't answer this question. All of his answers are geared to the radiologist that will actually be reviewing the PET / CT imagery by computer. Therefore, this SUV setting that I'm asking about isn't an issue for the reading radiologist as he can adjust, zoom, focus, etc. right off of the computer to his liking. The problem is that the printed sheets that I bring to my wife's docs are fixed at the one setting. It would be nice to know what affect the SUV setting has on the imagery. Like John and I discussed. Different SUV setting #s may very well lighten or darken the images, lesions, artifacts, etc. Sort of makes the films of limited use to the docs that I hand them to if the SUV settings differ and the doc isn't able to factor that variable correctly into his analysis, esp. for comparison from one test to the next. I've notice with other imaging techniques, esp. x-ray, that the brightness / darkness of the image(s) can vary quite a bit from one exam to the next. My wife also has alot of metal in her back which gives off alot of streaking artifact effect in her spine. P.S. I noticed that my wife's PET prints have several settings imprinted on them but no SUV setting. Interestingly, her PET / CT prints have none of those PET settings imprinted. Just her basic I.D. with the SUV setting that I'm asking about. The format may vary from company to company. Her PET / CT scans were performed by Alliance Imaging, Inc. B Quote Link to comment Share on other sites More sharing options...
hollyanne Posted March 3, 2006 Share Posted March 3, 2006 Bill - I could be COMPLETELY WRONG -- but I don't think the the SUV is an actual setting by the technician, but rather a measurement/marker of the primary mass/disease....check these links and see if this helps you understand the SUV (if I am right!) http://www.msit.com/phys_art17.html http://www.medscape.com/content/2003/00 ... 2_fig.html The higher the number, the "hotter" the activity, the lower the "colder." Let us know what you find out. Holly Quote Link to comment Share on other sites More sharing options...
hollyanne Posted March 3, 2006 Share Posted March 3, 2006 Did some more research.... "Standard uptake values (SUV) measure the intensity of tracer identified on the PET study. It is generally accepted that a higher SUV is more likey to represent malignancy in the primary area as opposed to scaring or inflammation." So, SUV IS a marker for the primary spot -- so her PET showing a lower SUV from the first PET means that for thre particular mass they are measuring, it has slowed.... Hope that helps. I have some time on my hands and love google! Holly Quote Link to comment Share on other sites More sharing options...
blaze100 Posted March 4, 2006 Share Posted March 4, 2006 Hi Bill, I did a search and found a user manual for PET scan software. It includes the settings info for techs using the scanner. Various parameters can be displayed along the side and bottom of images. It appears to me that the scanner will print an SUV value out next to the picture when the "cross hairs" are placed over a particular spot, or region of interest. Also there is reference to how SUV is calculated using patient weight, and measured uptake over region of interest, and area of region of interest on page 31 (if I remember right). I am sending the address just in case it may be of use to you. www.urmc.rochester.edu/smd/Rad/handbook.pdf I know the overall exposure of the film you're looking at could be darker or lighter than previous film, but I think the software actually calculates the SUV. I can see how this could be confounding when we meet with Docs to visually compare scans. It has just never come up when I look at my PET films with my docs. I have had a doc say an especially dark copy of one of my chest x-rays was useless for comparative purposes. Hope this helps. Barb Quote Link to comment Share on other sites More sharing options...
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