Data compression of x-ray images

Radiological imaging generates large volumes of data which have to be stored for diagnosing and archiving. To reduce this amount of data technical recommendations are needed to specify under which conditions and to what extent digital image data may be compressed. For this reason, a consensus conference of the German Roentgen Society (Deutsche Röntgengesellschaft – DRG) dealt with the topic of data compression for medical DICOM images.
SSK recommends not to exceed the compression factors published by the consensus conference when compressing DICOM images in order to maintain the full diagnostic image quality. The compression factors published refer to the compression algorithms JPEG and JPEG2000. Physicians with the necessary expertise in radiological protection have to assure that the selected compression method and the archiving system maintains the necessary diagnostic image quality.
Following these recommended maximum compression factors guarantees for diagnostic as well as archiving purposes – according to current knowledge – compliance with both the medical and radiological protection requirements of the German national regulations (Röntgenverordnung – RöV), in particular Article 28 (5) sentence 2 RöV “X-ray images may be compressed for archiving on electronic storage media if it can be guaranteed that their diagnostic validity is preserved”.
After five years at the latest the recommendation for the compression of radiological image data should be re-evaluated as to whether it still complies with any new knowledge available by then.

The provisions of the RöV (2003), which expired on December 31, 2018, have been transferred to a revised StrlSchV, which came into force on December 31, 2018. Section 28 (5) Sentence 2 RöV (2003) has been replaced by Section 127 (3) Sentence 2 StrlSchV (2018), "Data can be compressed if it is ensured that the diagnostic information is retained."

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