DICOM PS3.17 2024a - Explanatory Information

AAAAA.3 Acquisition Examples

Three common acquisition examples illustrate the breadth of Photoacoustic Image applications:

  1. Photoacoustic Standalone Image - a study with multiple optical wavelength images acquired over time. No complementary modality images are acquired.

    1. Photoacoustic Single Wavelength Standalone Image - a study with multiple images of one optical wavelength scanned repeatedly across the target over different time points (microscopy use case).

  2. Photoacoustic/Ultrasound Coupled Acquisition - a study with multiple optical wavelength images and ultrasound images acquired over time.

  3. Stationary tomographic 3D Photoacoustic/Ultrasound Coupled Acquisition - a study with multiple optical wavelength images and ultrasound images acquired over time where the transducer is mounted on a tomographic frame.

As illustrated in Section AAAAA.3.1, Section AAAAA.3.2 and Section AAAAA.3.3, the acquisition examples focus on the application of the Dimension Index.

AAAAA.3.1 Example 1: Photoacoustic Standalone Image

The following is a non-comprehensive illustration of an encoding of Photoacoustic data captured without a conventional ultrasound system in either handheld or stationary acquisition mode.

At each of M Temporal Positions, N optical excitation wavelengths are applied in rapid succession and images acquired for each wavelength (in this example, N=2). Although the images at each Temporal Position are separated by some milliseconds, they are nominally at the same temporal position.

Photoacoustic (PA) Standalone Example

Figure AAAAA.3.1-1. Photoacoustic (PA) Standalone Example


AAAAA.3.1.1 Photoacoustic Single Wavelength Standalone Image

A Photoacoustic single wavelength standalone image would be a sub-case of Example 1 (Figure AAAAA.3.1.1-1). In a Photoacoustic Microscopy example, Photoacoustic Image frames are produced by raster-scanning an object at one Temporal Position. One complete acquisition sequence produces a single 2D or 3D image. A repetition of the bespoke scanning sequence in stationary mode capturing a new time point of the same imaged object will increment the Temporal Position Time Offset only.

Example 1 Subcase: Photoacoustic (PA) Single Wavelength Standalone Acquisition

Figure AAAAA.3.1.1-1. Example 1 Subcase: Photoacoustic (PA) Single Wavelength Standalone Acquisition


AAAAA.3.1.2 Photoacoustic Dimension Index Sequence For Examples

The encoding examples in Section AAAAA.3.1, Section AAAAA.3.2 and Section AAAAA.3.3 follow the same Dimension Index Sequence structures. For brevity, the generic structure is illustrated in this section to be applied in each example. The Dimension Index Sequence for all Photoacoustic files in the examples is described in Table AAAAA.3.1.2-1.

Table AAAAA.3.1.2-1. Photoacoustic Example Dimension Index Sequence

Attribute

Tag

Value

Comments

Dimension Index Sequence

(0020,9222)

%item

>Dimension Organization UID

(0020,9164)

1.2.3.4

UID for the Photoacoustic Image Object.

>Dimension Index Pointer

(0020,9165)

(0020,930D)

Temporal Position Time Offset

>Functional Group Pointer

(0020,9167)

(0020,9310)

Temporal Position Sequence

%enditem

%item

>Dimension Organization UID

(0020,9164)

1.2.3.4

UID for the Photoacoustic Image Object.

>Dimension Index Pointer

(0020,9165)

(0020,9301)

Image Position (Volume)

>Functional Group Pointer

(0020,9167)

(0020,930E)

Plane Position (Volume) Sequence

%enditem

%item

>Dimension Organization UID

(0020,9164)

1.2.3.4

UID for the Photoacoustic Image Object.

>Dimension Index Pointer

(0020,9165)

(0018,9825)

Excitation Wavelength Sequence

%enditem

%item

>Dimension Organization UID

(0020,9164)

1.2.3.4

UID for the Photoacoustic Image Object.

>Dimension Index Pointer

(0020,9165)

(0018,9807)

Image Data Type Sequence

%enditem


AAAAA.3.1.3 Photoacoustic Standalone Image Per-Frame Example

In this encoding of the example shown in Figure AAAAA.3.1-1, the first frame of the image is shown for two optical wavelength images (Table AAAAA.3.1.3-1 and Table AAAAA.3.1.3-2). For brevity, examples of Photoacoustic attributes are provided in Section AAAAA.3.4.

Table AAAAA.3.1.3-1. Photoacoustic Standalone Example, Wavelength 1, Frame 1

Attribute

Tag

Value

Comments

Coding Scheme Identification Sequence

(0008,0110)

>Coding Scheme Designator

(0008,0102)

99ACME

In the Image Data Type Sequence (0018,9807), Blood Oxygenation XYZ Level is not defined by CID 7180; a private extension is being used.

...

Excitation Wavelength Sequence

(0018,9825)

>Excitation Wavelength

(0018,9826)

800

Optical wavelength 1 (𛌠1) is 800nm.

...

Shared Functional Groups Sequence

(5200,9229)

...

>Image Data Type Sequence

(0018,9807)

>>Image Data Type Code Sequence

(0018,9836)

>>>Code Value

(0008,0100)

445566

>>>Coding Scheme Designator

(0008,0102)

99ACME

>>>Code Meaning

(0008,0104)

Blood Oxygenation XYZ Level

>>>Context Group Extension Flag

(0008,010B)

Y

>>>Context Group Local Version

(0008,0107)

20230323

>>Context Group Extension Creator UID

(0008,010D)

1.3.4.34

...

>Reconstruction Algorithm Sequence

(0018,993D)

>>Algorithm Name

(0066,0036)

WL-800

A manufacturer-specific algorithm for images as applied to the excitation wavelength of 800nm.

...

Per-Frame Functional Groups Sequence

(5200,9230)

%item

...

>Frame Content Sequence

(0020,9111)

>>Dimension Index Value

(0020,9157)

1\1\1

...

>Plane Position (Volume) Sequence

(0020,930E)

>>Image Position (Volume)

(0020,9301)

0\0\0

...

>Temporal Position Sequence

(0020,9310)

>>Temporal Position Time Offset

(0020,930D)

0

...

>Photoacoustic Excitation Characteristics Sequence

(0018,9821)

>>Excitation Wavelength

(0018,9826)

800

nm

>>Excitation Energy

(0018,9823)

11

mJ

>>Excitation Pulse Duration

(0018,9824)

8

ns

...


Table AAAAA.3.1.3-2. Photoacoustic Standalone Example, Wavelength 2, Frame 1

Attribute

Tag

Value

Comments

...

Excitation Wavelength Sequence

(0018,9825)

>Excitation Wavelength

(0018,9826)

1064

Optical wavelength 2 (𛌠2) is 1064nm.

...

Shared Functional Groups Sequence

(5200,9229)

...

>Image Data Type Sequence

(0018,9807)

>>Image Data Type Code Sequence

(0018,9836)

>>>Code Value

(0008,0100)

110819

>>>Coding Scheme Designator

(0008,0102)

DCM

>>>Code Meaning

(0008,0104)

Blood Oxygenation Level

...

>Reconstruction Algorithm Sequence

(0018,993D)

>>Algorithm Name

(0066,0036)

RC_Long

A manufacturer-specific algorithm for images as applied to the excitation wavelength of 1064nm.

...

Per-Frame Functional Groups Sequence

(5200,9230)

%item

...

>Frame Content Sequence

(0020,9111)

>>Dimension Index Value

(0020,9157)

1\1\2

...

>Plane Position (Volume) Sequence

(0020,930E)

>>Image Position (Volume)

(0020,9301)

0\0\0

...

>Temporal Position Sequence

(0020,9310)

>>Temporal Position Time Offset

(0020,930D)

0

...

>Photoacoustic Excitation Characteristics Sequence

(0018,9821)

>>Excitation Wavelength

(0018,9826)

1064

nm

>>Excitation Energy

(0018,9823)

43

mJ

>>Excitation Pulse Duration

(0018,9824)

8

ns

...


DICOM PS3.17 2024a - Explanatory Information