# Using Nuclear Magnetic Resonance to Detect Cancer in Tissue > This 1974 patent describes a method and apparatus using nuclear magnetic resonance (NMR) to measure how quickly certain atomic nuclei in a tissue sample return to their normal energy state, helping to distinguish cancerous from healthy tissue. - **Patent:** US 3789832 - **Original title:** Apparatus and method for detecting cancer in tissue - **Owner:** Individual - **Granted:** 1974 - **Status:** Public domain (expired) - **Times cited:** 83 - **Field:** biotech, medical_devices, semiconductors, software ## What it does This patent details a way to detect cancer by looking at the behavior of atomic nuclei within a tissue sample. It involves placing the tissue in a special machine (a nuclear induction apparatus) that uses magnetic fields. First, the nuclei are energized to a higher energy state using magnetic radiation. Then, the machine measures how long it takes for these energized nuclei to return to their normal state. This measurement, called relaxation time (specifically spin-lattice and spin-spin relaxation times), is different for normal and cancerous tissues. By comparing these measured times to known standards for healthy and cancerous tissue, doctors can determine if cancer is present and how aggressive it might be. For example, claim 2 mentions using water protons as the indicator nuclei, and claim 3 describes actuating two magnetic energy sources to achieve this. ## What it does NOT cover - Detecting cancer using methods other than measuring NMR relaxation times. - Methods that do not involve comparing measurements to established standards for normal and cancerous tissue. - Detecting cancer in non-mammalian tissue (though the principles might be similar). - Using nuclei other than those exhibiting deviant behavior in cancerous tissue as the primary indicator. ## The clever bit The core innovation was realizing that the different molecular environments in cancerous cells, particularly concerning water content and structure, would cause specific atomic nuclei (like protons in water) to relax back to their normal energy state at measurably different rates compared to healthy cells. This provided a biophysical basis for distinguishing between normal and malignant tissues using NMR. ## Real-world examples 1. Early MRI scanners 2. Magnetic Resonance Spectroscopy (MRS) for tissue analysis 3. Modern MRI machines used in hospitals worldwide ## Why it matters This patent is foundational for Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) in medicine. While MRI is primarily used for imaging, the underlying principles of measuring nuclear relaxation times, as described here, are crucial. This work by Raymond Damadian was a significant step towards non-invasive diagnostic tools that revolutionized medical imaging and cancer detection. ## Frequently asked questions ### What does Using Nuclear Magnetic Resonance to Detect Cancer in Tissue cover? This 1974 patent describes a method and apparatus using nuclear magnetic resonance (NMR) to measure how quickly certain atomic nuclei in a tissue sample return to their normal energy state, helping to distinguish cancerous from healthy tissue. ### Who owns patent US 3789832? Individual owns this patent, granted in 1974. ### 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 3789832 cited by? This patent has been cited by 83 later patents that build on its ideas. ### What problem does this patent solve? This patent is foundational for Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) in medicine. While MRI is primarily used for imaging, the underlying principles of measuring nuclear relaxation times, as described here, are crucial. This work by Raymond Damadian was a significant step towards non-invasive diagnostic tools that revolutionized medical imaging and cancer detection. ### What does this patent NOT cover? Detecting cancer using methods other than measuring NMR relaxation times. **Full plain-English explainer:** https://patentbrief.org/patent/us/3789832/mri-magnetic-resonance-imaging **Original patent:** https://patents.google.com/patent/US3789832 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [Using Radioactive Antibodies to Find Tumors Inside the Body](https://patentbrief.org/patent/us/3927193/ivermectin) — 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. - [How Early CT Scans Created Detailed Body Images](https://patentbrief.org/patent/us/3778614/ct-scanner-hounsfield) — This 1973 patent describes a method for using X-rays from many angles to build a detailed 2D image of the inside of a body, like a slice of a CT scan. - [Removing Radio Interference from Portable MRI Scans](https://patentbrief.org/patent/us/12189012/eva-suit) — A method to clean up MRI images by using external sensors to detect and subtract outside radio interference, allowing portable scanners to work outside shielded rooms. - [How to Take 3D Pictures Inside Human Tissue Using Near-Infrared Light](https://patentbrief.org/patent/us/RE38800/digital-video-recorder-dvr) — A system that uses flexible fiber optic cables to map the inside of complex body parts by shining light through them and measuring how it scatters. - [AI System for Analyzing Medical Images Using Magnification-Aligned Transformers](https://patentbrief.org/patent/us/20260080696/method-and-system-for-analyzing-pathological-images-based-on-magnification-align) — This 2025 patent describes an AI system that analyzes medical images, like those from pathology slides, by using a special 'Transformer' model that understands how image details change with magnification.