Working knowledge.

• Autores: Mark Fischetti
• Localización: Scientific American, ISSN 0036-8733, Vol. 291, Nº. 2, 2004, págs. 92-93
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • The article looks at medical imaging systems. Medical imaging helps doctors see injuries and disease directly, so they do not have to rely on external exams or exploratory surgeries. Several tomography techniques have spread widely. Computed tomography (CT), which creates images with x-rays, is good at showing sharp contrasts in bone and tissue density, indicating broken bones, blood clots and kidney stones. If machine cost and speed improve only a bit further, CT could also take over most standard x-ray procedures, says C. Carl Jaffe, professor of internal medicine at Yale University. In positron emission tomography, a patient is injected with a radioactive element that produces photons. Because the element binds to molecules such as glucose, the emissions reveal the relative rates at which cells consume these molecules, a marker of cell metabolism. Unusual activity can indicate cancer cells, neurological diseases such as Alzheimer's, the malignancy of tumors, and brain activity during mental processes. Magnetic resonance imaging detects subtle fluctuations in the magnetic properties of hydrogen nuclei.