If a PSMA-PET scan finds your prostate most cancers is “PSMA-positive,” it means that you’ve no less than one metastatic tumor with excessive ranges of PSMA, making you eligible for a kind of remedy referred to as PSMA remedy, or PSMA-targeted radioligand remedy. Phrases like SUV, SUVmax, and SUVmin in your report present extra particulars in regards to the most cancers.
What SUV Means
Within the report, you might even see the time period “radiotracer uptake,” referring to areas within the physique the place the tracer has amassed as a result of it has hooked up to the PSMA on cells.
These areas will present up as vivid spots of various levels within the pictures from the PET scan, and a measurement of this brightness (how a lot accumulation there may be) known as a normal uptake worth, or SUV.
“The SUV values are quantitative metrics,” Iravani says, “a type of variety of how a lot [radiation] occurred in a selected quantity.”
Importantly, vivid spots or uptake don’t essentially imply most cancers. Varied organs within the physique, together with the small intestines, liver, kidneys, and salivary glands, additionally categorical PSMA that the radiotracer can bind to.
The liver is usually used as a reference organ because it takes up a extremely predictable quantity of radiotracer. Areas within the scan which are brighter or have larger SUV values than the liver could point out metastatic tumors.
SUVmax vs. SUVmean
SUVmax refers back to the highest SUV worth of all the intense spots inside a selected area of curiosity in your scan, says Daniel Sentana, MD, a medical oncologist with the Dana-Farber Most cancers Institute in Boston, noting that the brightest spot with essentially the most radiotracer uptake “tends to counsel that is a spot the place there are extra most cancers cells.” SUVmean, then again, is a measurement of the common quantity of tracer uptake throughout that area, he says.
Suppliers use each SUVmax and SUVmean to assist information a remedy plan and make an informed guess on how responsive your most cancers might be to PSMA remedy. In addition they think about different elements like tumor quantity (what number of lesions there are), as a result of SUVmax and SUVmean aren’t absolute markers of how nicely your most cancers goes to reply to PSMA remedy, Dr. Sentana says. “We nonetheless can’t make full suggestions about whether or not you need to or you shouldn’t get it simply because [your scan] doesn’t have a certain quantity of SUVmean or SUVmax.”
If You Have a Excessive SUV Quantity
A excessive SUV quantity signifies that your tumor cells categorical rather a lot PSMA or that you’ve a whole lot of most cancers cells expressing PSMA, which the scan is constructed to search out.
It additionally means you’re doubtless eligible for PSMA remedy, which works utilizing a drug referred to as lutetium Lu-177 vipivotide tetraxetan (Pluvicto) that attaches to PSMA after which releases most cancers killing radiation on to tumor cells.
Iravani suggests not focusing an excessive amount of on SUV numbers as a result of these metrics are extra related to the consultants who interpret the scans. For sufferers, the situation, quantity, and measurement of the metastatic lesions are “extra vital than SUV, per se,” he says.
