[Comparison of the image quality of a storage phospor system and a flat-panel detector in feline thoracic radiography].
OBJECTIVE
The aim of the study was to compare the image quality of radiographs obtained with a storage phosphor (SP) system and a flat-panel detector (FD). Furthermore, the influence of different exposure settings was investigated.


METHODS
In a prospective study a series of lateral thoracic radiographs of 45 normal cats were acquired by use of a standard SP-system and an opto-direct FD. From each animal four radiographs were taken with exposure settings adjusted to achieve sensitivity (S)-values of the system-specific dose indicator of S180 and S360. In a blind study, five observers rated the presentation of anatomical structures (trachea, cranial lung field, sternum, cardiac silhouette, caudal thoracic field) by use of a four-point scale (1 - excellent; 4 - insufficient).


RESULTS
Independent of the detector-type and the exposure level applied the mean values of the ratings of the respective image criteria ranged from 1.14 to 1.67. In both systems higher doses related to better rating results. While comparing the detectors on the basis of identical exposure settings the FD demonstrated superior performance.


CONCLUSIONS
At the dose levels investigated both detectors reveal an image quality sufficient for the depiction of subtle, low-contrast thoracic structures in cats. Therefore, the detectors can be recommended for practical use in small animal radiology. In both systems a dose reduction of 50% in comparison to the original level (S180) is possible without a substantial loss of information. Because of the superior quantum efficiency the dose saving potential of the FD might be even higher. Alternatively, the higher dose efficiency can be utilised to improve image quality in comparison to the SP-system with identical exposure settings.
Dr. med. vet. Eberhard Ludewig (Dipl ECVDI; FTA für Radiologie; FTA für Kleintiere), Klinik für Kleintiere, Veterinärmedizinische Fakultät der Universität Leipzig, An den Tierkliniken 23, 04103 Leipzig, E-Mail: ludewig@kleintierklinik.uni-leipzig.de.
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Ludewig
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Werrmann
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Gosch
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Oechtering