Using Radioactive Antibodies to Find Tumors Inside the Body
A 1973 method for finding cancer tumors by injecting patients with radioactive antibodies that attach to tumor-specific proteins, allowing doctors to scan for their location.
Original patent title: “Localization of tumors by radiolabelled antibodies”
A 1973 method for finding cancer tumors by injecting patients with radioactive antibodies that attach to tumor-specific proteins, allowing doctors to scan for their location. Granted to F Hoffmann La Roche AG in 1975 with 4 claims and 66 forward citations.
Key facts
Coverage
What does this patent actually cover?
The patent describes a diagnostic technique where a patient is injected with an antibody that has been tagged with a radioactive isotope. This antibody is specifically designed to bind to carcinoembryonic antigen, a protein often found in high levels near certain tumors. Once the antibody attaches to the tumor, the radioactive tag emits gamma rays. A photoscanning device then detects these rays to map exactly where the tumor is located within the body.
The gap
What does this patent NOT cover?
- Does not cover the use of antibodies for treating or killing tumor cells.
- Does not cover scanning methods that use non-radioactive markers like fluorescent dyes.
- Does not cover antibodies that target proteins other than carcinoembryonic antigen.
- Does not cover isotopes with a half-life significantly longer than 8 days.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The invention cleverly repurposed the immune system's natural ability to recognize specific proteins to act as a delivery vehicle for radioactive tracers, effectively turning the tumor itself into a beacon for medical scanners.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Radioimmunoscintigraphy
Early cancer diagnostic imaging
Targeted diagnostic nuclear medicine
Why it matters
The bigger picture
This patent represents an early milestone in the field of radioimmunodetection. It helped establish the concept of using the body's immune system components as 'homing devices' to deliver diagnostic signals directly to diseased tissue, a principle that eventually evolved into modern PET and SPECT imaging techniques.
Filed
May 18, 1973
Granted
December 16, 1975
Market context
Who's building on this
Companies in this space
Companies like Roche, as well as modern developers of radiopharmaceuticals and diagnostic imaging agents, continue to refine the use of monoclonal antibodies for targeted delivery. This field has expanded into theranostics, where the same targeting molecule is used for both diagnosis and therapy.
Market impact
This patent helped validate the commercial viability of using biological molecules for diagnostic imaging. It set the stage for the development of more sophisticated radiolabeled tracers and contributed to the growth of the nuclear medicine industry by providing a clear protocol for tumor localization.
Claim 1 — Plain English
What this patent covers
The patent describes a diagnostic technique where a patient is injected with an antibody that has been tagged with a radioactive isotope. This antibody is specifically designed to bind to carcinoembryonic antigen, a protein often found in high levels near certain tumors. Once the antibody attaches to the tumor, the radioactive tag emits gamma rays. A photoscanning device then detects these rays to map exactly where the tumor is located within the body.
The clever bit
The invention cleverly repurposed the immune system's natural ability to recognize specific proteins to act as a delivery vehicle for radioactive tracers, effectively turning the tumor itself into a beacon for medical scanners.
What it does not cover
- Does not cover the use of antibodies for treating or killing tumor cells.
- Does not cover scanning methods that use non-radioactive markers like fluorescent dyes.
- Does not cover antibodies that target proteins other than carcinoembryonic antigen.
- Does not cover isotopes with a half-life significantly longer than 8 days.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Early stage
Citation count
36/40
Highly cited
Claim breadth
3/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$54K – $173K
Midpoint $108K · expired or expiring · industry ×3.0
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
4 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Primus, F. J., & Hansen, H. J. (1975). Using Radioactive Antibodies to Find Tumors Inside the Body (U.S. Patent No. 3,927,193). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/3927193/ivermectin
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does Using Radioactive Antibodies to Find Tumors Inside the Body cover?
A 1973 method for finding cancer tumors by injecting patients with radioactive antibodies that attach to tumor-specific proteins, allowing doctors to scan for their location.
Who owns patent US 3927193?
F Hoffmann La Roche AG owns this patent, granted in 1975.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 3927193 cited by?
This patent has been cited by 66 later patents that build on its ideas.
What problem does this patent solve?
This patent represents an early milestone in the field of radioimmunodetection. It helped establish the concept of using the body's immune system components as 'homing devices' to deliver diagnostic signals directly to diseased tissue, a principle that eventually evolved into modern PET and SPECT imaging techniques.
What does this patent NOT cover?
Does not cover the use of antibodies for treating or killing tumor cells.
Patent monitoring