Photoacoustic section imaging with integrating detectors

Photoacoustic  section  imaging  is  a  method  for visualizing  structures  with  optical contrast  in selected  layers  of  an  extended  object.  In  order  to avoid  resolution limitations  that  are  due  to commonly used ultrasound detectors of finite size, we propose  the  use  of  extended,  integrating cylindrical  elements  for  focusing  the acoustic detection  into  the  selected  section.  Two  imaging methods  based  on piezoelectric  and  optical detection  are  presented.  Resolution  limits  and results on zebra fish are demonstrated

Thermography and thermoregulation of the face

BACKGROUND: Although clinical diagnosis of thermoregulation is gaining in importance there is no consistent evidence on the value of thermography of the facial region. In particular there are no reference values established with standardised methods. METHODS: Skin temperatures were measured in the facial area at 32 fixed measuring sites in 26 health subjects (7–72 years) with the aid of a contact thermograph (Eidatherm). A total of 6 measurements were performed separately for the two sides of the face at intervals of equal lengths (4 hours) over a period of 24 hours. Thermoregulation was triggered by application of a cold stimulus in the region of the ipsilateral ear lobe. RESULTS: Comparison of the sides revealed significant asymmetry of face temperature. The left side of the face showed a temperature that was on the average 0.1°C lower than on the right. No increase in temperature was found following application of the cold stimulus. However, a significant circadian rhythm with mean temperature differences of 0.7°C was observed. CONCLUSION: The results obtained should be seen as an initial basis for compiling an exact thermoprofile of the surface temperature of the facial region that takes into account the circadian rhythm, thus closing gaps in studies on physiological changes in the temperature of the skin of the face