关于DICOM属性(0018,9346)中"1)"标识含义的技术咨询

Hey there, let's unpack what that recurring "1)" means in the CTDI Phantom Type Code Sequence (0018,9346) field you've spotted across 2000 DICOM images.

First, a quick primer: this DICOM tag is part of the CT Image module, and it's used to specify the type of phantom (a standardized test object) used to calculate the CT Dose Index (CTDI) for that scan.

Here's the breakdown of the "1)" you're seeing:

• The "1)" is a formatted display of the Code Value (0008,0100) sub-element within this code sequence. The raw code value here is 1.
• Per DICOM standard definitions, a Code Value of 1 in this sequence corresponds to the Head Phantom — the standard-sized phantom used to calibrate and measure CT dose for head scans.
• Some imaging device manufacturers append the parenthesis formatting (like "1)") when outputting this field, but the core meaning ties directly to the head-specific dose measurement phantom. For context, a "2)" in this field would typically map to the Body Phantom for torso scans.

To confirm this, you can inspect the full structure of the 0018,9346 sequence: it should include three key sub-elements:

• Code Value (0008,0100): Will show the raw numeric value 1
• Coding Scheme Designator (0008,0102): Usually set to DCM (DICOM Standard Coding Scheme)
• Code Meaning (0008,0104): Will explicitly state "Head Phantom"

内容的提问来源于stack exchange，提问作者user4420255