DICOM Letter Ballot: Supplement 229

DICOM Letter Ballot Supplement 229

Hello All,

Please review the following letter ballot and advise by March 8th, 2023 if you have any comments or concerns.

Letter Ballot for Proposed DICOM Supplement 229
Photoacoustic Imaging

Issued: 2023-02-02
Ballot closes: 2023-03-09

The following is a Letter Ballot seeking DICOM Standard Committee (DSC) approval of the Proposed Supplement 229: Photoacoustic Imaging. Only the officially designated voting representatives (or alternates) of the Members of the DICOM Standards Committee are invited and entitled to cast a ballot. Others on the Committee receive a copy of this ballot as a courtesy so that all will be apprised of anticipated revisions or extensions to the DICOM Standard.
Scope and Field of Application

This Supplement to the DICOM Standard introduces a new IOD and a new storage SOP Class for encoding and storing photoacoustic images.
Photoacoustic (PA) imaging is an imaging modality that enables imaging optical absorption in biological tissues with acoustic resolution. Contrast is generated through absorption by chromophores that range from intrinsic absorbers such as hemoglobin and melanin to extrinsic agents such as indocyanine green (ICG) or diverse types of nano-particles. In principle, excitation at multiple wavelengths allows the modality to discriminate individual chromophores. Prospective applications in the space of clinical imaging range from classification of breast cancer lesions through screening of sentinel lymph nodes to assessment of inflammation. Photoacoustic Imaging is in widespread use in preclinical research labs and is currently being translated to clinical applications in first commercial implementations.

Many (but not all) PA implementations integrate active pulse/echo ultrasound in a hybrid imaging system to capitalize on well-established contrast for anatomical information. The scope of this IOD is the Photoacoustic (PA) image. Complementary images such as pulse/echo ultrasound are represented by their native DICOM IODs. Albeit fusing PA images with US images for display is the presently most common scenario, the particulars of the fusion are beyond the scope of this IOD but examples are provided. PA images represent image output generated by the input of one or more optical excitation wavelengths.
The following items are considered out of scope:

● Photoacoustic specific SR file implementation is reserved for a later supplement.
● If a PA device produces an image with no PA optical image, the SOP class of the structural image (e.g. ultrasound) will be used
● If a PA device creates a single image component by fusing the structural image to the PA image for display as a single image (burned in), it will use the SOP class of the structural image.
● A closely related imaging modality is Thermoacoustic imaging (TAI) which uses microwave radiation to excite the tissue (in contrast to light pulses). The specific characteristics of TAI were not addressed in this supplement and focus was given to photoacoustic imaging as defined herein, where excitation is limited to pulsed light. Hence, this modality is excluded in this supplement to limit the scope of the present supplement.

Supplement 229 can be accessed on the FTP:

Word Document format:
ftp://medical.nema.org/medical/dicom/Supps/LB/sup229_lb_photoacoustic.docx

PDF format:
ftp://medical.nema.org/medical/dicom/Supps/LB/sup229_lb_photoacoustic.pdf

PowerPoint Overview:
ftp://medical.nema.org/medical/dicom/Supps/LB/sup229_lb_photoacoustic.pptx