William L. Rollwitz

Transient NMR quantitative measurements

The transient nuclear magnetic resonance technique is briefly described. Application of this technique allowed quantitative observation of the protons in the oil, water and solid material in a single corn kernel and on a corn kernel baked at 107 C. These results along with measurements on lyophilized foods are discussed.

On-stream NMR measurements and control

Four examples are described in which nuclear magnetic resonance (NMR) measurements provided quantitative analyses with an accuracy of 1% of the amount measured. In the first instance, the amplitude of the NMR absorption of hydrogen was combined with the weight and volume of the sample to give a moisture determination in starch. The second NMR instrument used no sample weight and the amount of moisture in a flowing stream of Milo maize was measured by means of only the amplitude of the NMR absorption of hydrogen. The third instrument used the second harmonic of the NMR absorption from hydrogen to measure the amount of moisture in a flowing process stream of starch or other hygroscopic material without weighing. The last example described how the amplitude and area of the aluminum and hydrogen NMR absorptions, respectively, can be combined to measure the per cent aluminum and per cent hydrogen in a flowing process stream, again without weighing.

DETERMINATION OF BODY WATER BY NMR

Publisher Summary A method found to fulfill rapid and nondestructive method for ensuring body water is that of hydrogen nuclear magnetic resonance. Developments from other research and development programs have given NMR instrumentation which has a large volume. This equipment has been modified and used to make hydrogen NMR measurements on live animals. This chapter describes the instrument, the measurements made and the results obtained. When nuclei such as those of hydrogen are placed in a steady magnetic field, they interact with that field in such a way that they absorb energy at a frequency particular to the isotope which contains the nucleus. If the hydrogen atoms are only in water, then the NMR absorbed energy is directly proportional to the quantity of water. The hydrogen nuclei exchange their absorbed energy in two ways. One way is with neighboring nuclei from the same isotope. The second exchange mechanism is between the absorbing nuclei and their surroundings usually called the lattice. As a result of continuous developments over 32 years, designs, components and magnets were available for sample volumes of up to 14’ high, 24’ wide, and 30’ deep.

IN-VIVO SCREENING FOR BREAST CANCER WITH NMR

Publisher Summary One of the most often mentioned areas for potential application of nuclear magnetic resonance (NMR) is cancer diagnosis; another is heart attack detection even if one is not imminent; a third is the diagnosis of brain abnormalities. It is possible to make an NMR instrument much smaller in size, complexity and cost when it is dedicated to performing measurements on a specific part of the body such as the female breast. This chapter discusses such an instrument that is used to give three types of data: (1) the free induction decay (FID) signals following a single 90o pulse, (2) the echo amplitude following a 90°-τ-18o dual-pulse sequence as a function of the pulse spacing τ from which the graph giving T 2 can be obtained, and (3) the FID amplitude following the second 90° pulse in a dual-pulse sequence as the pulse spacing is varied to permit graphing the amplitude as a function of pulse spacing so that T 1 can be calculated. The results of these measurements are recorded and computer analyzed. The analysis gives the density of the hydrogen nuclei in the water in the breast, the number of binding levels for water, and the relaxation times T 1 and T 2 for each binding level for water in the sensitive area which is a slice through the breast perpendicular to the length axis.