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INTERPRETING A PET SCAN

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Posted 9/11/2013 2:15 AM (GMT 0)
Had my first PET scan this week. Radiologist impressions are: (1) Sclerotic foci in the sacrum, right ilium and body of L3 without significant FDG uptake and (2) Atrophic erector spinae musculature on the right at L5-S1 and associated with FDG uptake. This is likely related to advanced right L5-S1 facet arthropathy. Can someone interpret this for me. My Onco says scan shows no mets?? The Old Sailor
Posted 9/11/2013 2:18 AM (GMT 0)
Based on my PET scan earlier this year, I did learn that the "without significant uptake" remarks are usually good things. The no mets part is good, my friend, that is what I got out of mine from my oncologist too, and with a fast climbing PSA of 60 in April, its great that no mets are big enough to be picked up at this point.

Glad to see you post, our dear friend Padre is still looking out for both of us.

David
Posted 9/11/2013 2:22 AM (GMT 0)
David, when the Pope was asked which saint he prayed to, he immediately said St. Theresa. Give it a try. The Old Sailoir
Posted 9/11/2013 3:43 AM (GMT 0)
Sounds like good advice
Posted 9/12/2013 2:49 AM (GMT 0)
You had an FDG PET scan that included your lower spine and pelvis, including the lumbar vertebrae (which are numbered from L1 to L5, going from top to bottom), the sacrum (below that, S1-S5), and the ileum -- the pelvic bones on both sides of the sacrum.

(1) You had thickening of the bone at 3 places on your spine. Such thickening may or may not be a sign of bone mets from prostate cancer. Thickening is part of the body's protective mechanism to seal off anything that doesn't belong there.

FDG, the tracer used in the FDG PET scan, is a radioactive form of glucose that is taken up by many cancers (many cancers grow quickly and get their energy for that from glucose), but not especially by prostate cancer until it is well advanced, and so it has limited usefulness. (Prostate cancer seems to prefer to metabolize fat rather than glucose.) The typical technetium bone scan doesn't show up with PCa until mets are quite large, and so it is less useful. The NaF18 PET is more sensitive, has become more widely available, and will probably be covered by insurance. Other specialty PETs for detecting smaller bone mets include C11 Choline or Acetate, F18 Choline or FACBC.

PET scans are often combined with CT scans to better visualize the lesions. Lately, they are combining them with MRIs to get an even better view.

(2) There is arthritis in one of the joints of your spine, with some atrophy of the supporting muscle. Inflammation often increases glucose uptake, which is why the FDG showed up there.

So as I interpret your report (and I am not a radiologist), you had no bone mets that are detectable with a FDG PET scan.
Posted 9/12/2013 3:04 AM (GMT 0)
Allen,

Nice write up.

Question for you. Through Myers I get a F18 pet/ct bone scan every 6 months. He doesn't seem to care if I get a regular CT. The CT part of the f18 bone scan doesn't look at soft tissue as well does it?

Thanks,
Jerry
Posted 9/12/2013 7:21 AM (GMT 0)
Jerry,

The PET/CT will light up when there are soft tissue mets as well, but not as clearly as the PET/MRI combo. The PET part will light up no matter where the met is. I'm guessing that the reason he doesn't much care about the CT part is because that kind of clarity is irrelevant for you. The precision becomes relevant only when they intend to zap them with SBRT, as when there are 5 or fewer mets. Then they would need to localize them precisely to avoid toxicity. He may be more interested in just monitoring any spread. But I'm just guessing -- I think it's a good question to ask him.

- Allen
Posted 9/13/2013 1:51 AM (GMT 0)
Allen,

Thanks....so, a F18 Pet/CT bone scan will show soft tissue Mets if they exist, similar to a regular CT scan?
Posted 9/13/2013 2:43 AM (GMT 0)
To my knowledge, a regular CT scan will not typically show soft tissue mets, unless the tumor is quite large. The NaF18 PET may show bone and other mets of a certain size. It's all about size and early detection -- we want to know about the smaller mets. These fancy PET scans light up when certain metabolic abnormalities typical of PCa tumors occur, but their ability to detect small lesions differ.

The USPIO MRI that John T had can detect small lymph node lesions, although it may give lots of false negatives (but few false positives).

The new FACBC PET (in clinical trials at Emory) may have the highest sensitivity of any of the new generation of imaging tests for both soft tissue and bone mets. It's sensitivity seems to be even better than C11 Choline PET.
Posted 9/13/2013 3:04 AM (GMT 0)
I've had a spot radiated a couple of years ago that showed up on F18. Since then I did ask Myers if I should go to Orlando for the sensitive mri. He told me that there wasn't anything to look for at this point. Guess he is waiting for psa and other markers to show progression.
Posted 9/22/2013 7:34 PM (GMT 0)
Are there any studies that give survival if no mets but rising PSA versus mets with rising PSA.  Sorry I waited so long to ask this question.   The Old Sailor
Posted 9/22/2013 7:37 PM (GMT 0)
Do you mean rising PSA while on Lupron?
Posted 9/22/2013 8:08 PM (GMT 0)
Yes, while on Lupron. l started Casodex with Lupron in July 2012 and was undetectable for about a year. On 7/9/13 PSA was .011 and on 9/9/13 went to 0.12 September. Mayo Onc wanted to put me on Provenge but Medicare said not until PSA reached .50. Onc took me off Casodex on 9/9/13 to see what will happen. He said about 40% of men on casodex actually have a reduction in PSA when Casodex is terminated. The Old Sailor
Posted 9/23/2013 4:50 AM (GMT 0)
Hello everyone sorry to bother you all, but I saw this post and was wondering if you could maybe answer or explain something to me.

I have had RA/Lupus for a very long time, these are auto immune diseases. I always have inflammation in my body, no matter that I take high dose steroids, and have done so for almost 13 years now.

My Pulmonary Dr has ordered a PET/CT for me for the 1st week of November. They found a nodule in my right lung in June of this year, on an x-ray. They ordered a CT in July, I had it done and I now have a matching nodule in my left lung. Both nodules are in the upper lobes. My Doc isn't sure what it is, so she would like the PET/CT done to try to give her more information.

I was diagnosed in May with LGL Leukemia and now I have these nodules. I'm worried that the PET/CT scan is going to light up like a Christmas tree, due to my leukemia and all the inflammation I have in my body from my RA/Lupus. Plus in May I stopped doing radiation treatments to try to get rid of a huge wart on my thumb. I had five 5 treatments will this affect the scan too? Will this happen, and will the Doctors be able to determine what is truly a problem or not?

I'm quite worried as we spoke with my Pulmonary Dr she made it sound like I'll be under going a biopsy of the nodules in the lungs not to long after the scans are done. She also hinted that she may even request the surgeons remove the nodules from the lungs. This scares the you know what out of me. Any thoughts, opinions, or suggestions. I'm really sorry to bother you all, but there isn't a general cancer forum here and I know the folks here are so good at helping someone out.

Finally, my Rheumy has me on Methotrexate to treat my RA/Lupus. I take it in injectable form, I give myself a shot weekly. He recently increased the amount I'm taking and I've noticed that I've begun to get many mouth sores, and a raw tongue. Hard to eat now, I'm sure none of you take this exact medication, but I know some do take chemo. Is this a common reaction to chemotherapy drugs.

I hope that you didn't mind me asking a few questions about the PET/CT scan. Hope each and everyone of you have a good week. Saying prayers for all of you, as you battle this tough cancer.

Hugs,
Barbara
Posted 9/23/2013 6:10 AM (GMT 0)
Barb, I can't fully answer your question, but it is a good one for sure. As a rule, a PET/CT scan would normally light up most anything active in you. With all your combined issues, past and present, I would think the Radiation Oncologist that has to read your scan(s) will be kept busy separating the past from the present, but should be able to determine within reasonable, what is going on with that nodule on your lung. At least enough to determine if a biopsy of it is warranted. I know that is the last thing you need at this point with all that is on your plate.

Good luck.

David, your pain buddy
Posted 9/23/2013 7:48 AM (GMT 0)
Old Sailor,
I'm afraid I don't know enough about your history to answer your question. There are so many variables that enter into it: age, previous therapy, salvage therapy, timing and response to hormone therapy, PSA kinetics, co-morbidities, etc. - to name a few. It sounds like your oncologist at Mayo is really on top of things. Provenge before bone mets show sounds like a good idea to me, so does early use of Xgeva or Zometa. He's right that Casodex will sometimes start feeding the cancer. Maybe he can get you on a clinical trial of Zytiga or Xtandi for non-metastatic castration-resistant PC.

- Allen
Posted 9/25/2013 1:31 AM (GMT 0)
Allen, I had open RP 9/09 Very good path report except gleason 4/5. undetectable PSA until 2/10. Started SRT 4/10 but PSA actually increased some after SRT. PSA hit 1.0 in 11/10 so Started HT with PSA undetectable until 7/13. PSA starting to climb again to 0.012. Next PSA in October. Thank you for all your info etc. The Old Sailor
Posted 9/25/2013 2:37 AM (GMT 0)
Allen,

I see your comment about xgeva. I value your opinion...would you mind reading this and commenting? I am still deciding on this:

https://www.healingwell.com/community/default.aspx?f=35&m=2777274

Thanks..
Posted 9/25/2013 2:57 AM (GMT 0)
Sailor,

Just bought a nice wall print of our dear friend Padre and hung it in my study. Reminds me of you every time I see it.

Hope you are well.

David
Posted 9/25/2013 5:35 AM (GMT 0)
Jerry,
Rather than kidnap this thread, I'll comment there.
Posted 9/25/2013 12:30 PM (GMT 0)
The location of uptake on a PET scan depends on the type of isotope used for the PET scan.
An FDG scan (glucose) is a fancy "sugar" map. Any tissue that takes up glucose takes up FDG. This would include tumors (if metabolically active). Even a normal muscle in someone moving a muscle during the scan will show increased uptake of FGD. Some types of fat (brown fat) will normally show increased uptake. Areas of arthritis will be active too. That is why the simultaneous CT scan is done ...to localize where the uptake is to help determine the cause. So if one sees increased FGD uptake in the spine and arthritis in that spot, that can be assumed to be the cause. If a dense area of bone is seen corresponding with the uptake, then it is likely a metastasis. The PET part of a PET/CT scan is relativley low resolution and it is hard to localize where the FDG uptake is without a CT scan done at the same time.
Other PET scans use 18f naf, which is a really a super sensitive bone scan.
Other isotopes are used, some experimental and others less available because of their short half life.
FDG and 18F can be done at most PET facilities.
Diagnostic radiologists are the ones that interpret the scans. The interpretation is part science and part art.

Post Edited (starr15) : 9/25/2013 6:40:35 AM (GMT-6)

Posted 9/25/2013 7:34 PM (GMT 0)
David, how nice of you to think of me when you look at PP. I have a statue of him in my bedroom and when I look at it I ask him to help you and several other friends who are battling illness. Take care, the old sailor.
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