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.

What it covers

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 doesn't 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.

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.

Real-world examples

• 1.Early MRI scanners
• 2.Magnetic Resonance Spectroscopy (MRS) for tissue analysis
• 3.Modern MRI machines used in hospitals worldwide