Comparison of fluorescence detection capability.

<p>The concentration of ICG solution are 0.0001, 0.0005, 0.001, 0.002, 0.003, 0.004, 0.006, 0.008, 0.01, 0.02, 0.03, 0.08, 0.1 mg/ml respectively. The black line is the detection results by IVIS Lumina III and the red line is by the NIR Camera in our projective surgical navigation system.</p

The relationship between projection bias and height difference.

<p>(a) Schematic diagram of the projection bias induced by height variation after registration, plane α is the registration plane and there is a bias l on the observation plane β; (b) The triangle caused deviation in (a).</p

Benchtop and Animal Validation of a Projective Imaging System for Potential Use in Intraoperative Surgical Guidance

<div><p>We propose a projective navigation system for fluorescence imaging and image display in a natural mode of visual perception. The system consists of an excitation light source, a monochromatic charge coupled device (CCD) camera, a host computer, a projector, a proximity sensor and a Complementary metal–oxide–semiconductor (CMOS) camera. With perspective transformation and calibration, our surgical navigation system is able to achieve an overall imaging speed higher than 60 frames per second, with a latency of 330 ms, a spatial sensitivity better than 0.5 mm in both vertical and horizontal directions, and a projection bias less than 1 mm. The technical feasibility of image-guided surgery is demonstrated in both agar-agar gel phantoms and an ex vivo chicken breast model embedding Indocyanine Green (ICG). The biological utility of the system is demonstrated in vivo in a classic model of ICG hepatic metabolism. Our benchtop, ex vivo and in vivo experiments demonstrate the clinical potential for intraoperative delineation of disease margin and image-guided resection surgery.</p></div

Fluorescence imaging projective surgical navigation system.

<p>(a) Schematic diagram of the projective surgical navigation system; (b) Projective surgical navigation system in working mode.</p

In vivo, ICG concentration–time course in mouse liver following ICG injection.

<p>(a) The nude mouse before dissection at 3 hours after ICG tail intravenous injection; (b) After the mouse is sacrificed by cervical vertebra dislocation, we dissect its abdomen and observe the anatomy map. (c) The fluorescence image captured by NIR camera. The area into the white frame is used to calculate fluorescence intensity. (d)The image of nude mouse under projective navigation system captured by nude eye. (e) Corresponding fluorescence intensity basis time courses.</p

Experimental results that simulate the effect of the surgical scene motion on the imaging lag of the projective navigation system.

<p>(a-f) show the projected pattern (gray dot) and the actual object (black dot) at the following moving speeds: 1, 2, 3, 4, 5 and 6 m/min, respectively.</p

Phantom study to show the projective accuracy as the function of the height difference between the projection plane and the reference plane.

<p>(a)—(e): As the projection plane moves from 40 mm above to 40 mm below the registered reference plane, the projected image is biased from left to the right of the actual phantom. (c): If the projection plane is identical to the reference plane, the projected image and the actual phantom are co-registered without bias. (f) Linear relationship is observed between the projection bias and the height difference without height correction, while the projection bias is controlled within 1 mm for all the height differences after the height correction algorithm is applied.</p

Demonstration of the image-guided tumor resection procedure using an ex-vivo tumor simulating tissue model.

<p>(a) Tissue model observed by the projective navigation system before resection. (b) Model observed by the IVIS small animal imaging system before resection. (c) Model observed by the projective navigation system after resection. Arrows correspond to the identified residual lesions. (d) The IVIS system also captures two residual lesions (black arrows).</p

Comparison of the projective system with other NIFR systems.

<p>Comparison of the projective system with other NIFR systems.</p

The achievable spatial resolutions of the projective navigation system.

<p>(a) The test pattern is 71 mm×36 mm, consisting of horizontal and vertical stripes with thicknesses from 0.5 to 4 mm and the separation distances from 0.5 to 4 mm. (b) The projected image overlaid with the printed test pattern. (c) Side by side comparison between the test pattern and the projected image.</p