The short answer
A bone scan checks for abnormal areas or damage in the bones, including cancer that has spread to bone. A PET scan uses a tracer, often a form of sugar, to find areas where cells use more energy, such as cancer. Both can be useful in cancer care, but they are ordered for different questions.
A bone scan focuses on bone activity.
A PET scan looks for areas where a tracer shows increased metabolic activity.
Neither test is interpreted by the picture alone; clinical context matters.
Ask what question the scan is meant to answer and what follow-up could be needed.
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This page is for people who have been told they need a bone scan or a PET scan and want to know how the two differ. It covers what each scan is like and what the results can and cannot tell you.
The short answer
A bone scan and a PET scan both use small amounts of a radioactive tracer. But they look for different things. A bone scan focuses on abnormal areas or damage in the bones. A PET scan shows where cells use more sugar, as cancer cells often do.
What a bone scan is actually like
You get an injection of a small amount of radioactive material into a vein. As it travels through your blood, it collects in problem areas of bone. Those areas show up as "hot spots" on the scan. The National Cancer Institute says bone scans check for abnormal areas or damage in the bones.
What a PET scan is actually like
You get an injection of a tracer, often a form of radioactive sugar. Cancer cells usually use more sugar than normal cells, so the scan can help find them in the body. The scan makes three-dimensional pictures. Your imaging center will tell you how long to wait after the injection and what to do to prepare.
What a hot spot does and doesn't mean
A "hot spot" on a bone scan shows an abnormal area. It does not by itself tell you the cause. Your team interprets any finding alongside your cancer type, symptoms, prior scans, and lab results, not as a stand-alone answer.
What happens after a suspicious finding
A concerning area may lead your team to suggest more tests. Ask what they are looking for and why.
How long results usually take
How soon a bone scan or PET scan is read, and how soon someone talks it through with you, varies from one imaging center and one scan to the next. Ask your team when the report is expected, who will explain it to you, and whether it will appear in your patient portal first.
What to ask next
- What question is this scan meant to answer, and what tracer is being used?
- What could be causing a hot spot?
- Would any finding need more imaging or a biopsy to confirm it?
Sources
Common questions
Does a hot spot on a bone scan always mean cancer?
Not by itself. A hot spot shows an abnormal area. Your team interprets results with your history, other imaging, and sometimes follow-up tests.
Why would a PET scan be ordered instead?
A PET scan can show areas of increased tracer uptake that may help find active cancer or assess treatment response, depending on the cancer type and tracer.
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Sources last checked: 2026-07-19 what this meansLast updated: 2026-10-16Next planned review: 2027-07-19
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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