ABSTRACT
We developed a multimodal imaging system, combining noncontact photoacoustic imaging and optical coherence tomography (OCT). Photoacoustic signals are recorded without contact to the specimens' surface by using an interferometric technique. The interferometer is realized within a fiber-optic network using a fiber laser at 1550 nm as source. The fiber-optic network allows the integration of a fiber-based OCT system operating at a wavelength region around 1310 nm. Light from the fiber laser and the OCT source are multiplexed into one fiber using wavelength-division multiplexing. The same focusing optics is used for both modalities. Back-reflected light from the sample is demultiplexed and guided to the respective imaging systems. As the same optical components are used for OCT and photoacoustic imaging, the obtained images are co-registered intrinsically in lateral direction. Three-dimensional imaging is implemented by hybrid galvanometer and mechanical scanning. To allow fast B-scan measurements, scanning of the interrogation beam along one dimension is executed by a galvanometer scanner. Slow-axis scanning, perpendicular to the fast axis, is performed utilizing a linear translational stage. We demonstrate two-dimensional and three-dimensional imaging on agarose phantoms.
Subject(s)
Multimodal Imaging/methods , Photoacoustic Techniques/methods , Tomography, Optical Coherence/methods , Equipment Design , Fiber Optic Technology , Humans , Imaging, Three-Dimensional/methods , Phantoms, Imaging , Spectrum AnalysisABSTRACT
In a cross-sectional study dating from april 94 to march 96 we have investigated length and weight of 2610 girls and 2865 boys (age 4-18 years) at nursery schools and schools in Saarland. Thus we could provide first normative data for this region of Germany. Compared with data that have been collected between 1968 and 1989 at Dortmund, Bonn, Hamm and Jena, we found an increase in height of 2 cm for girls and boys aged 15-18 years. Apart from this finding, no further differences have been observed. Compared with international data, 18-year-old females and males in Saarland show large body heights: their average heights were 169 and 182 cm, respectively. Unfortunately, body weight of children of the Saarland is high, too. Children in Saarland were on average 1.5-6.6 kg heavier than those of the Dortmund study or other international studies. Studies have revealed that, according to the ECOG criteria, people of the Saarland are more obese than in other European countries. As a consequence of our study we request an institution for auxology to be founded which enables immediate reaction. This not only implies medical view points but also practical aspects of daily life (e.g. height of chairs or tables at schools). It is important to note that no changes have been made so far. Standards for height and weight should be updated every ten years. This should be a collaborative task between public health services and pediatric endocrinologists.
