Reading Your DOTATATE PET — Report

A Krenning score of 3 means uptake at that site is clearly higher than the liver background — a level of somatostatin receptor expression that the radiologist considers strong. Whether it is high enough to support a particular treatment, such as PRRT, depends on your cancer type, the number and distribution of lesions, and your overall fitness. The score is one input into that decision, not the whole answer. Ask your oncologist to explain what the score means specifically for your situation.

DOTATATE and DOTANOC both bind to somatostatin receptors using Ga-68 as the radioactive label. They differ slightly in which receptor subtypes they bind to — DOTANOC has a somewhat broader binding profile — but in clinical practice the two are used interchangeably at most centres, and the choice is usually determined by which tracer is available when you book. The interpretation and the Krenning scoring system are the same for both. If you have had one tracer before and are switching to the other, your team may note this in the report.

No uptake, or very low uptake, at a lesion means the somatostatin receptors are not strongly active at that site. This matters because several treatments for neuroendocrine tumours — particularly PRRT — target those receptors. If a lesion is not receptor-positive, it is less likely to respond to receptor-targeted treatment. This does not mean there are no options; your oncologist will explain what other approaches apply. It can also sometimes mean the lesion is a different type of tissue than expected, which is useful information in itself.

A higher SUVmax on a DOTATATE scan means the receptors at that site are more active — it does not directly measure how aggressive the cancer is. Strong uptake can actually be a favourable sign if you are being considered for receptor-targeted treatment, because it suggests the treatment has a target to work on. Tumour aggressiveness in neuroendocrine disease is assessed separately, through the Ki-67 index and tumour grade on your pathology report. The DOTATATE scan and the biopsy answer different questions, and your oncologist uses both.

No. The pituitary gland and spleen show uptake on almost every DOTATATE scan because they carry high concentrations of somatostatin receptors as a normal part of their function. The same is true of the liver, kidneys, and sometimes the adrenal glands. The radiologist expects to see these and describes them as physiological uptake to distinguish them from findings that need clinical attention. If you are unsure whether a particular site in your report is physiological or suspicious, ask your oncologist to show you the images and explain.

Look for the words new, previously not seen, or de novo in the Findings or Impression section. The radiologist explicitly notes any site that did not appear on your last scan. If this is your first DOTATATE scan, there is no comparison to make, and the report will describe what is present without the language of change. For follow-up scans, the comparison section is usually the most clinically significant part of the report — your oncologist will focus there when deciding on next steps.