PET and CT scans differ?

I was told that the Pet tends to pick up more as the glucose and radioactive stuff that they inject go to cancer cells so they can see them.

I had a pet scan when they were trying to establish lymph involvement and if a lesion on my liver that looked suspicious was or wasn't.  As the liver didn't pick up the glucose they said it wasn't cancer just a lesion.  Lymph nodes not so lucky.

Hi Daisydoo38. Thank you so much for taking the time to reply. I understand the difference between the types of scan. Just a bit confused as to how or rather why my CT scan seemed to miss the growth of new Tumours and the PET scan picked them up.....I just wondered if anyone else had similar experiences. Thanks x

Hi my experience with scans I had numerous scans ct/bone the one that found my cancer was a pet scan. I believe the PET SCAN in lay mans terms looks at you more closely (magnified). So the question I have asked is way don't the NHS give the pet scan first. I feel its not for me to put my finding on this forum 

Hi

I am so sorry to hear your news. Cancer in five or six different new places is a bit of a shocker, I would imagine. 

I have had soooo many scans and I’ve come to two conclusions. The first is that there’s more to them than a lay person could hope to understand. The second is that they are a bit like a map or a grainy aerial photograph. So a map might show a church at a given location but it’s not until you go there in person that you can know whether it’s a ruin, been converted into a home or open for communion on Sunday. Scans are a bit like that. A CT scan might show there is a lump, say, or an enlarged lymph node. A PET scan will show whether the lump is active metabolically, and therefore likely to be cancer, but you’d have to get in there with a needle to take a sample to look at under a microscope to be 100% sure. Sticking needles in lumps is often neither desirable nor possible so doctors look at scans over time to see how lumps change (or don’t) in response to treatment to get a clearer idea of what they are. Does this make some kind of sense? 

Personally I try not to get too hung up on the fine details of scan results. I always get a copy of my scan reports and read them carefully. Over time they’ve raised queries about this node or that lesion, some of which have shown themselves not to be cancer at all. It’s the big picture I’m interested in, such as the treatment decisions my team make based on scan results. 

So for example, early last summer I had a CT scan that highlighted a patch of abnormal tissue around a major blood vessel in my thorax. My team suggested an MRI to look in more detail but the radiologists advised it wouldn’t show more information. So we watched and waited and my team got in experts for their evaluation. By the autumn, the consensus emerged that this was a tumour growing into the blood vessel and causing a clot to form. So they called in a haematologist who prescribed blood thinners to dissolve the clot. As a patient, I experienced worsening oedema as the tumour thrombus grew and this reduced as the blood thinner did its work. 

I think what I’m trying to say is don’t get too hung up on which scan showed what and when. That’s looking backwards when maybe it’s more important to look forward and understand what the scan results mean for you and your treatment. Does it change as a result of this? Are these new lesions in the lymph system or do they indicate the cancer has spread to a new organ? That’s what would interest me. 

I hope this is helpful. I’m not a doctor and so this is just my layman’s attempt to understand and navigate my way through my own experiences 

xx

What a great reply and thank you......I’ve never been given a copy of my scan report, just a synopsis by my Oncologist of the outcome of the MDT meeting.....is that something I could ask for. I also have only ever seen a couple of my scans, both times I was already in hospital and sneaked a peak!  Don’t get me wrong in terms of skill and knowledge I think I am lucky enough to have a completely dedicated and focus Oncologist, team and in a great hospital, but her approach is sometimes to play it all down a bit, over the years she has realised I am better at dealing with the stark reality and need the detail, but I do still have to push a little to get the facts from her.....prehaps next time I will ask to see the scans and their areas on concern....thanks again x

Hi

Oh phew! I’m glad that helped. Yes you can ask for your scan reports.

I’ve had a look at CT images with my oncologist - we were trying to work out if pain in my hip was related to deteriorating hips from age or referred pain from my kidney. It was fascinating. I could see my normal kidney, size of a walnut, compared to the kidney where the tumour thrombus had blocked the blood supply and killed it. This was the size of my fist. It was quite shocking to see it but it helped me visualise better where the pain originated. However, I’m treated at the clinical trials unit where the doctors have more time and aren’t rushing to get through a clinic list. I’m not sure my oncologist would have time to do this in the normal run of things. 

Xx

Hi , I have metastatic melanoma diagnosed in July 2015, and have never had a PET scan, only CT scans with contrast every 3 months. At my hospital they have an app that gives me access to the scan narrative, prior to this I used to ask them to cut and paste the narrative into the letter they send after the consultation. I have seen a scan on screen once, but as I had no idea what I was looking at I haven’t asked again. The important bit for me is to know if the treatment is still working and how well, I used to imagine that if things got worse immunotherapy would be stopped and that concerned me. My other concern was if it’s got worse and I’m still on the same treatment should immunotherapy be changed to a targeted therapy (as I’m BRAF positive). The answer for me has been to keep going on Pembrolizumab. They are saying that from my last scan they can tell that although I have a new enlarged node that it is melanoma that is dying. My hospital have always said that if I have questions after my appointment I can contact the specialist nurses and they will liaise to get an answer, this was really useful for me when they were considering surgery that would not necessarily improve longevity. 

I always think that when they say something I wasn’t expecting, that the curve ball disrupts my thought pattern, it makes it difficult to refocus and ask questions at the time. I’m not sure if you think they missed something on a previous scan or that it’s strange things have changed so much from the last scan. I think the uncertainty is often difficult, but hope and attitude makes things easier, I’m glad you’ve mentioned that you have a good opinion of your hospital and team. 

Best wishes

Hi ,

I always ask for a copy of my scan report and also my blood test results.  They are not always easy to interpret but if I have them then I can either ask the oncologist the next time we meet or look up the medical terms to try and get some understanding.  I have a few other conditions other than cancer and I find the blood tests in particular useful for keeping an eye on these.  These reports should be made available to you for free.

At my hospital you can also ask for a copy of your scan to be provided on a CD.  I did this once not long after I was diagnosed and after putting it in my computer it took me about half an hour to work out which was my chest and which was my back.  I'm sure that with a lot more playing about on the computer I could see things a bit better but my knowledge of the human body is basic at best and unless I had a doctor guiding my through it I doubt I could find the tumours even though some of them are quite large.  I decided not to bother purchasing a CD again.  At the time (about 5 years ago) the charge at my hospital was £10.

I do find the scan report useful as I am on a trial and sometimes feel that the doctors are monitoring for the trial and that I sometimes need to remind them that although I am happy with how the trial is progressing I am concerned about my overall health.  In my case they monitor specific tumours to see how the treatment is going, from my point of view I am just as interested in how the more recent and smaller tumours in my lungs are responding.

wishing you all the best,

Gragon x

Hi,

I always ask for copies of my reports and they now send the link on email ti view my scans.

there is a measuring tool so you can measure the size of the tumours and see how much they have grown. The radiologist in Bristol seem to given up measuring or counting mine they just say whether it is progressive growth or not according to RECIST.

i like more information and  like to view it myself because some of them just don’t bother to give you much information and the oncologist won’t show me his scans which he can access just goes by the report.

Thank you everyone....I will definitely be asking for my scan reports in future....I wasn’t even aware this was an option and also a copy of my scans.....thank you so much for all the helpful advice xx