DCMTK

Currently, the dcm2json tool supports a non-standard extension, enabled by the --encode-extended command line option, that encodes binary floating point numbers that are either "not a number" or infinity as 'nan' and 'inf', respectively:

  "00720076": {
    "vr": "FL",
    "Value": [
      -inf,
      0,
      inf,
      nan
    ]
  }

DICOM CP 2275 (which is currently a working draft) will introduce official values for infinity and nan, and these will probably be different from the values currently written by dcm2json, i.e. "Infinity" and "NaN" (with quotes, i.e. encoded as JSON string). Once the CP has been finalized, dcm2json should be adapted accordingly, and the extended encoding mode should then be made the default.

Thanks to Mathieu Malaterre <mathieu.malaterre@gmail.com> for pointing this out.