DICOM Enhanced Imaging Objects
History The legacy CT object was standardised back in 1993 by the DICOM committee. In 2003 the DICOM WG 21 has decided that it is necessary to create a new CT object to meet the needs of modern CT technology that had evolved substantially.
Furthermore, new applications such as cardiac CT, gated studies, perfusion CT, CT fluoroscopy, contrast tracking and post-processing are not supported by the current standard at that time.
To create a DICOM Image Histogram Module, users of DicomObjects can use the DicomImage.Histogram method, which returns an array containing the distribution of the raw pixel values.
Hounsfield Units (HU) are used in CT images it is a measure of radio-density, calibrated to distilled water and free air.
HUs can be calculated from the pixel data with a Dicom Image via two methods.
The first (and harder) method involves using the Slope and Intercept value from the Dicom image and applying it to a target pixel.
HU=m\*P+b where: m is the Dicom attribute (0028,1053) “Rescale slope” b is the Dicom attribute (0028,1052) “Rescale intercept” P is the value of that particular pixel in the pixels array.