Table 4.

The specific advantages and disadvantages of the four imaging modalities.

	NIR-II FI	OCT	PAI	DOT
Common Advantages	1.Non-invasive 2.High biocompatibility 3.No radiation 4.High resolution 5.No barriers to multimodal treatment combination 6.Accurate characterization and localization
Common Disadvantages	1.Relatively poor depth compared to PET, MRI, or X-ray based techniques 2.Unstable image quality due to optical limitations and thyroid gland structure near the trachea
Unique Advantages	1.Flexible modifiability for targeted imaging 2.Precise data for clinical staging 3.Real-time feedback for surgical navigation	1.Convenient, short imaging time 2.Real-time feedback for surgical navigation	1.Detects small vessels that are not detected by color Doppler ultrasound 2.Displays key functional data (e.g., oxygen saturation)	1.Three-dimensional imaging 2.Imaging of thick tissue bodies
Unique Disadvantages	1.Strong background signal of tumor tissue with increased vascularity may interfere with the imaging of FI 2.Two-dimensional imaging	1.OCT has the most limited penetration depth (1–2 ​mm) and intraoperative thyroid imaging is limited to the exposed surface and superficial tissues to be performed.	1.Susceptible to motion artifacts and difficult to control image quality	1.Long imaging time
Penetration Depth	Near NIR-II laser depth up to 5–20 ​mm	500 μm-2 mm	Penetration depth and resolution are inversely proportional to the frequency of the ultrasound detector used (center frequency of 4–6 ​MHz and a bandwidth of 0.1–10 ​MHz for an imaging depth of 2–4 ​cm)	1–1.5 ​cm