Table 1 Performance specifications of existing FGS systems and FAR-Pi.

From: Frugal engineering-inspired wearable augmented reality goggle system enables fluorescence-guided cancer surgery

 

Existing Systems

FAR-Pi

 

Overhead and handheld cameras connected to displays and controller carts

Augmented reality NIR FGS implementations

Compatible with augmented reality or handheld implementation

Devices

SPY Elite, SPY Phi, PerkinsElmer Solaris, Fluobeam 800, Curadel FLARE, Quest Spectrum, PDE neo i and ii, VisionSense Iridium, SurgVision Explorer Air, Vitom ICG17,18,22

1) Single NIR channel system by Lee et al.33

2) Stereo dual white light and NIR system by Mela et al.27,29

3) Previous dual white light and NIR Cancer Vision Goggles (CVG) from our lab26,51

FAR-Pi

Resolution

100 μm for Solaris

50–300 μm for Fluobeam

50–500 μm for FLARE

Otherwise NR

NR Lee et al.

NR Mela et al.

320 μm @ 50 cm CVG

138–227 μm at distances between 35–65 cm

Depth of field

2 cm for Solaris,

2–3 cm for Fluobeam

Otherwise NR****

NR Lee et al.

NR Mela et al.

~ 2–3 cm for CVG,

20 cm

Irradiance

PDE neo 4 mW/cm2

Fluobeam 5 mW/cm2

SPY Elite ranges from 4 mW/cm2 to 31 mW/cm2

Otherwise NR

0–5 mW/cm2 Lee et al.

1–2 mW/cm2 in Mela et al.

5 mW/cm2 for CVG

Peak 22.5 mW/cm2 when surgeon 50 cm away

Field of view (FOV)*

Fluobeam 2.2 × 1.5–20 × 14 cm

PDE 5 × 5–10 × 6.7

Spy PHI 7.6 × 5.0–19 × 13

Spy Elite 19 × 14 cm

VisionSense 19 × 14 cm

NR for Lee et al.

Camera FOV 30 × 20 cm for Mela et al., illumination area NR

Illumination 20 cm2 > 4mW/cm2 for CVG

Camera FOV 50 × 40 cm

Illumination area 25–35 cm2 > 4 mW/cm2

Compatibility with OR lights

Not compatible - Fluobeam, PDE neo, SPY Elite, Iridium

Compatible - SPY PHI, Solaris, Spectrum, SurgVision

Not compatible***

Compatible

Fluorescence Sensitivity

50 pM VisionSense

1 nM Solaris

5 nM for Fluobeam and SPY Elite

10 nM for Spectrum

15 nM for PDE

NR for Lee et al.

40–60 nM for Mela et al.

1 nM for CVG (threshold SBR 1.2)

1 nM SBR > 1.2

5 nM SBR > 2

250 pM with 99 ms exposure at 22.5 mW/cm2 irradiance

Working Distance

Solaris: 75 cm

Fluobeam: 25–50 cm

SPY/Quest/PDE neo/Iridium: 30 cm

Spectrum: 5 cm

50 cm for Lee et al.

30 ± 10 cm for Mela et al.,

50 cm for CVG

50 cm

Latency

NR, external monitor display**

NR for CVG or Lee et al.,

< 100 ms for Mela et al.

~ 50 ms

Other

Wall-powered

Wall-powered

Battery-powered

  1. NR – not reported.
  2. *The field of view is reported in the literature but the specified field of illumination is not, we assume that in existing system illumination is provided over the entire field of view but in practice it may be a smaller area.
  3. ** Latency is not reported for external monitor displays, when using an external monitor display the latency has in general been estimated to be 50 ms53 for medical devices.
  4. *** Ambient light subtraction described in Mela 2021 et al. AR system23, but this was not an NIR system.
  5. **** Adjustable focus wheal for PDE neo ii allowing 5–30 cm focus76 but depth of focus not reported at fixed focus position.
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