Why Nuclear Medicine Physicians Get Sued: The Wrong Dose, the Extravasation, and the Misread Scan

By John Mahoney · June 2026 · 8 min read

Nuclear medicine is a low-frequency specialty to sue and one of the hardest to value, because its liability runs on two separate tracks. One track is therapeutic and procedural — radiopharmaceutical dosing errors, wrong-isotope and wrong-patient administrations, and infiltration injuries — and it carries a feature no other imaging specialty has: a federal regulatory "medical event" framework that can document the error for you before a complaint is ever filed. The other track is interpretive — a false-negative cancer read on PET or bone scan, a missed pulmonary embolism on a V/Q study — and those misses behave like radiology diagnostic claims, with the highest causation stakes in the specialty. An attorney who treats every nuclear-medicine intake as a "radiology" file will miss the regulated dose-error case entirely. This guide explains where nuclear-medicine liability actually lives, the cannot-miss failures behind it, and what separates a strong case from a weak one — for plaintiff and defense med-mal attorneys.

Disclaimer: This article is for informational purposes only and does not constitute legal advice. The patterns below draw on closed-claims literature, regulatory reporting frameworks, and specialty-society guidance that span different eras and definitions; treat them as directional, verify against the controlling jurisdiction and the applicable NRC or Agreement-State rules, and value any individual case on its own record.

The Frequency-and-Severity Reality

By frequency, nuclear medicine is a low-claim specialty. Like diagnostic radiology, it sits well below the procedural and surgical fields in how often physicians are named, and the dedicated nuclear-medicine physician is sued far less often than the interventionalist or surgeon. But the low count is deceptive, because a meaningful share of the exposure is captured in a parallel regulatory channel rather than the tort system: the "medical event", a reportable dose or administration error under the radiation-safety rules, which generates a documented agency record of exactly what went wrong. Many of these never become lawsuits, but when they do, the proof problem is unusually small.

Severity is split. Interpretive misses follow the radiology severity curve — a false-negative cancer or a missed PE can produce a high-value delayed-diagnosis or wrongful-death claim because the causation chain is long and the harm is severe. Therapy-dose errors are commonly reported in the literature as a distinct and serious category: an overdose of therapeutic radioiodine (I-131) or a Lu-177 radioligand-therapy error delivers absorbed radiation that cannot be recalled, with organ-specific injury that can be permanent. Extravasation and infiltration injuries vary widely — many are minor, but a significant radiopharmaceutical extravasation, particularly of a therapeutic agent, can cause local tissue and vascular injury and has drawn rising regulatory and litigation attention. The screening lesson is that two valuation models live inside this one specialty, and you must route every intake to the right one immediately.

The Dominant Allegation Types

Nuclear-medicine claims cluster into a therapy-and-administration group and an interpretive group, plus a communication thread that runs through both:

• Radiopharmaceutical dosing error / "medical event" — wrong dose, wrong isotope, wrong radiopharmaceutical, wrong route, or wrong patient, most consequential in therapeutic administrations such as I-131 for thyroid cancer or hyperthyroidism and Lu-177 radioligand therapy. The regulatory medical-event framework often pre-documents the deviation.
• Diagnostic error / misinterpretation — false-negative or misread PET, bone, cardiac-perfusion, V/Q, or thyroid scans. The classic high-severity miss is a false-negative for cancer or a missed pulmonary embolism on a ventilation-perfusion study.
• Failure to communicate a critical or unexpected finding — an actionable or incidental result that was on the images but never conveyed to the referring physician in time to act, a recurring and independent source of liability.
• Procedural and safety injury — significant extravasation or infiltration injury at the injection site, and complications of pharmacologic or exercise stress testing during cardiac-perfusion imaging.
• Radiation-safety screening failures — failure to screen for pregnancy or lactation before administering a radiopharmaceutical, exposing a fetus or breastfeeding infant, a small but high-emotion category.

The structural point: by count, the interpretive claims look like radiology, but the therapy-dose and medical-event claims are unique to this specialty and carry their own regulatory proof trail. Any intake should be triaged first on which side of that line it sits, because the merit analysis, the experts, and the damages are entirely different.

The Cannot-Miss Conditions and Failures

The conditions and failures that drive nuclear-medicine litigation are:

• Therapeutic radiopharmaceutical overdose or wrong-patient administration. The highest-control exposure: an I-131 dose intended for one patient or condition given to another, a calculation or unit error, or a Lu-177 radioligand-therapy administration that deviated from the written directive. Absorbed dose cannot be undone, and the medical-event record frequently establishes the deviation on its face.
• Missed cancer on PET or bone scan — a false-negative oncologic read or a failure to flag a suspicious focus, producing a delayed-diagnosis claim with a long causation chain.
• Missed pulmonary embolism on a V/Q scan — a misclassified or under-read ventilation-perfusion study in a patient who then deteriorated, one of the most severe interpretive exposures in the specialty.
• Misread cardiac-perfusion or thyroid study — a false-negative perfusion scan preceding a cardiac event, or a thyroid-uptake or scan misinterpretation that misdirected therapy.
• Significant extravasation, stress-test, and screening injury — substantial radiopharmaceutical infiltration with local tissue injury, a complication of pharmacologic or exercise stress during perfusion imaging, or a pregnancy/lactation screening failure before administration.

For the therapy side, the single most actionable screening question is the written-directive question: did the administered dose, isotope, route, and patient match the written directive and the order, and if not, was a medical event identified, reported, and disclosed? For the interpretive side, the decisive questions are whether the finding was on the images and whether a critical or unexpected result was communicated to the referring physician in time to change the outcome.

The Contributing Factors That Drive Payouts

Across nuclear-medicine claims, the recurring contributing factors are:

• Dose calculation, verification, and write-up process — the factor unique to this specialty: errors in computing or verifying a therapeutic dose, mismatches between the written directive and the administered activity, and breakdowns in the wrong-patient/wrong-isotope checks. The regulatory medical-event finding often sets the standard-of-care discussion in motion.
• Clinical judgment / interpretive process — false-negative reads, under-classification of a V/Q or perfusion study, and failure to flag a suspicious focus on PET or bone scan, which drive the high-severity delayed-diagnosis claims.
• Communication and result notification — failure to convey a critical, actionable, or unexpected finding to the referring physician in actionable time; in a missed-finding case the line between a defensible file and a paid claim is frequently whether the report was communicated and received, not whether the abnormality was visible.
• Radiation-safety and screening protocol — pregnancy and lactation screening, injection-site technique and extravasation monitoring, and stress-test patient selection and supervision; protocol gaps reframe the case around safety systems rather than a single physician.
• Documentation — the written directive, the dose record, the screening checklist, the injection note, and the communication log, which together decide whether a claim is paid.

Two of these are nuclear-medicine-specific levers. The first is the written-directive and medical-event record: in a therapy-dose case, the line between a defensible file and a paid claim is often whether the administered activity matched the directive and whether a reportable deviation was identified and disclosed — and that record frequently exists before the lawsuit does. The second is the communication trail on a critical finding: in a missed-PE or missed-cancer case, whether the abnormality was relayed to the referring physician in time can matter more than whether it was visible. Documentation rarely creates liability here, but it consistently decides whether a claim is paid.

Strong Case vs. Weak Case in Nuclear Medicine Malpractice

The same factors grade the file, and the framing is useful to both sides.

What makes a nuclear medicine case strong (plaintiff) / dangerous (defense)

• A therapeutic radiopharmaceutical — I-131 or Lu-177 — administered as the wrong dose, wrong isotope, or to the wrong patient, with a documented medical-event finding establishing the deviation from the written directive.
• A significant therapeutic-agent extravasation or infiltration injury with thin documentation of injection technique and no monitoring or mitigation note.
• A clear, named abnormality — a PE on a V/Q study, a cancer focus on PET — visible on the images that was misread or never communicated to the referring physician in time to act, supporting a strong loss-of-chance causation theory.
• A pregnancy or lactation screening failure before administration, exposing a fetus or breastfeeding infant, with an absent or unsigned screening record.

What makes a nuclear medicine case weak (plaintiff) / defensible (defense)

• A therapeutic administration that matched the written directive, the order, and the patient verification, with the dose calculation documented and no reportable medical event — the directive loop intact.
• An interpretive read that was reasonable on the images available, with a defensibly classified V/Q or perfusion study and a documented, timely communication of the result to the referring physician.
• A patient whose record shows declined therapy, missed follow-up imaging, or non-adherence that drove the delay rather than the read.
• A procedure performed to radiation-safety standards with a documented screening checklist, injection note, and stress-test patient selection and supervision.

Nuclear medicine rewards a fast triage. On the therapy side, the case lives or dies on the written directive, the dose record, and whether a medical event was identified and disclosed. On the interpretive side, it turns on whether the finding was on the images and whether the critical result was communicated in time, then on the loss-of-chance causation chain for the missed cancer or PE. Whichever side you are on, grading the file means matching the right model to the right claim and pressure-testing the expert who will carry it.

Bottom Line

Nuclear-medicine physicians get sued rarely, and the count understates the exposure because a large share of the dose-error universe lives in the regulatory "medical event" channel rather than the tort docket. The specialty hides two severity spikes: therapy-dose errors — wrong dose, wrong isotope, or wrong patient with I-131 or Lu-177 — that deliver irreversible absorbed radiation and often arrive pre-documented, and interpretive misses — a false-negative cancer on PET or bone scan, a missed PE on a V/Q study — that carry the long causation chains and the biggest dollars. The cannot-miss facts are the dose that did not match the written directive, the significant extravasation with no monitoring note, the critical finding that was never communicated, and the pregnancy or lactation screen that was never done. Whether you are screening these cases for the plaintiff or defending them, triage first to the right model — therapy-dose or interpretive — and grade the file on the written directive, the communication trail, and the safety record, not on the visible injury alone.

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