A comparison of analogue and digital techniques in upper gastrointestinal examinations: absorbed dose and diagnostic quality of the images.

This study was performed to investigate whether patient exposure and diagnostic quality of the image is significantly influenced by the introduction of digital image acquisition techniques. Evaluation was performed for three different techniques (analogue, analogue fluoro + digital radiography, digital) in examination of the upper gastrointestinal tract. The evaluation was done from data acquired in three different departments. Patient exposure was recorded as KERMA-area product (KAP) and the individual patient readings were normalised to a standard size patient. Image quality was assessed using visual grading with a reference image. The recorded KAP values were significantly higher (22.3 Gycm2) for the fully digital technique compared to the others (analogue 6.8 Gycm2, analogue + digital 3.6 Gycm2). This was due mostly to an increased number of exposures. The diagnostic quality of the image was, however, also regarded to be slightly lower for the technique giving the lowest patient dose with the smallest number of exposures (analogue + digital). The digital examination technique, as used in this study, thus resulted in significantly higher patient dose without any significant gain in diagnostic quality of the image.

Inter- and intraspecific variation of the nucleotide sequence of the cytochrome b gene in Cory's (Calonectris diomedea), Manx Shearwater (Puffinus puffinus) and the Fulmar (Fulmarus glacialis).

The cytochrome b gene of three European taxa of the family of Procellariidae was amplified from total DNA and sequenced. The sequence comparison shows that the Fulmar (Fulmarus glacialis) is significantly distinct from shearwaters, whereas Cory's (Calonectris diomedea) and Manx Shearwater (Puffinus puffinus) are closely related. Although the populations of C. diomedea can be distinguished morphologically, the sequences of cyt b differ only slightly between the Atlantic and Mediterranean subspecies (i.e. C. d. borealis versus C. d. diomedea) and do not reveal other population differences within subspecies.