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PET Scans and Melanoma Metastasizing

Had an emergency at the end of winter, ER doctor took a CT scan and saw a Nodule on my left lung at the bottom and also saw inflammation at my sentinel lymphoid. Strongly suggested I get a PET scan. Went to my regular doctor (who is an Internist) he arranged for Scan. Went fine. A different doctor read the scan. Told my doctor that there was no cancer anywhere. (He told me). Anyhow this Radiologist compared the PET scan to the CT scan done 2 weeks before at Emergency RM, not the CT scan done a year ago that showed a 11cm nodual. (Of course no change. Would something really change in 2 weeks?? That raised my eyebrow)

Anyhow here are my questions:
1. will a PET scan show ALL cancers in the body?

2. Is there a blood test that would show cancers?
(It really amazes me that I just sit and wait for it to visually show itself to my dermatologist.)

PS: I should also add that I have Transverse Mylitis (TM). I am waiting for Melanoma to metastasize. I had one spot removed. 7 out of 9 siblings (and me) have cancers. (One brother has had 4 cancers and is still alive after 6 years).

Thank you in advance for any advice/help you can give.

  1. Hi!

    Thanks for posting your questions on the site. PET scans detect cell growth and cancers in the body, but it does not detect all cancers according to the Cancer Canadian Society ( A study also showed that the cancers that typically don't show up in PET scans are "tumors with low glycolytic activity such as adenomas, bronchioloalveolar carcinomas, carcinoid tumors, low grade lymphomas and small sized tumors" ( As for skin cancer, it is most useful in people with more advanced stages of melanoma.

    I'm deeply sorry to hear that several of your family members have been affected by cancer. It truly is not an easy journey, but we hope you all are hanging in there. I'm keeping you all in my thoughts. Please let us know if you have any questions. We're always here to help!

    -Sidney, moderator

    1. Thank You

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