RESUMO
We report on the development of a passive millimeter-wave (MMW) imager for remote sensing, and the comparison of the experimentally acquired images with the theoretical images from our MMW scene simulator. The imager has an aperture diameter of 0.6m, and the detector and the imaging optics are mechanically raster-scanned over the scene to form an image. The angular resolution was experimentally found to be 0.4 degrees, which is close to the theoretical diffraction limit of 0.37 degrees, and the imager NEDT was measured to be 0.9 K. Qualitatively, simulated MMW imagery showed good agreement with an experimental MMW image.
Assuntos
Algoritmos , Monitoramento Ambiental/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Modelos Teóricos , Simulação por Computador , Micro-Ondas , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The authors performed thermoacoustic computed tomography (CT) with 434-MHz radio waves in five patients with documented breast cancer. Three of the patients underwent imaging before chemotherapy was initiated and two at the conclusion of their primary chemotherapy. In the former three patients, thermoacoustic CT demonstrated contrast enhancement in the region of the tumor. In the latter two patients, no contrast enhancement was seen, and pathologic examination after surgical resection of the area of original tumor confirmed complete remission of disease.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Acústica , Adulto , Idoso , Neoplasias da Mama/tratamento farmacológico , Estudos de Viabilidade , Feminino , Humanos , Mamografia , Pessoa de Meia-Idade , Ondas de Rádio , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
The authors evaluated images obtained with a prototypic thermoacoustic computed tomographic (CT) scanner constructed for use at 434 MHz, a promising radio frequency for detecting breast cancer. In one excised porcine kidney, acoustic energy emanating from the kidney was detected with transducers. The resultant electric signals were used to create a three-dimensional data set. Two-dimensional images reconstructed in multiple planes were compared with state-of-the-art T1- and T2-weighted magnetic resonance images. The renal outline, parenchyma, and collecting system were clearly delineated on the thermoacoustic CT images.