Patent ID: 7500953

Claim:
A method of enhancing detection for a specific object or distribution thereof in a body, comprising the steps of: (a) administering to said for detection of the object, if present, a nanoparticulate, the nanoparticulate having the following properties; i. it is a collection of at least partially metallic nanoparticles, having a most probable size and most probable absorption maximum at a selected wavelength or range of wavelengths, comprising shells with a negative value of the real part of the complex dielectric permeability wherein said shells are filled with a substance having a coefficient of thermal expansion in the range of 9.times.10.sup-2 mm.sup.3joule to 2. times.10.sup.3 nm .sup.3/joule, ii. it has a minimal characteristic dimension in the range from about 1 to about 3000 nanometers, and iii. it has a formed composition capable of producing thermal pressure either in said nanoparticulate or in said object greater than said object could produce as a result of step (b) in the absence of said nanoparticulate; (b) directing onto said body specific electromagnetic radiation having a wavelength or spectrum of wavelengths in the range from 3 nm to 300 mm selected so that the wavelength or wavelength spectrum is longer by a factor of at least 3 than the minimum characteristic dimension of said nanoparticulate, said nanoparticulate absorbing said electromagnetic radiation more than would one or more non-aggregated spherically shaped particles of the same total volume with a composition identical to said nanoparticulate, said nanoparticulate by such absorption producing an enhanced optoacoustic signal resulting from said absorption; (c) receiving said optoacoustic signal; (d) converting said received optoacoustic signal into an electronic signal characterized by at least one parameter selected from amplitude, frequency, phase, temporal profile, time of arrival, frequency spectrum, or a combination of any one or more of such parameters; and (e) presenting said signal for assessment of said at least one parameter by a human or a machine.