## 5 Cart-Based SCISCCO Prototype System for Lab and Hospital Use  
For use in laboratory and hospital settings at remote locations, a cart-based SCISCCO prototype system has been developed that integrates the hardware and software into a single, portable assembly. The ruggedness of the system was also tested for transporting to remote locations and operation within typical laboratory and hospital settings and being transportable within a hospital to various locations such operating rooms, the ICU, or the emergency department. High-level system schematics of the cart-based SCISCCO prototype are shown in Figure 21. The various components of the system (SC laser, optical system, electronics, and laptop for processing, as shown on the left side of Figure 21) are integrated into a cart system that can be rolled through standard hallways and doorways (right side of Figure 21). The rolling cart system has three levels: the top level comprises the super-continuum laser and laptop for processing, the middle level comprises the optical system hardware, and the bottom level comprises the electronics and lock-in amplifiers. Photographs of the assembled SCISCCO prototype are provided in Figure 22. In particular, Figure 22 illustrates (a) an isometric view of the SCISCCO prototype, (b) a front view (left), and (c) a side view of the prototype. Figure 21: High-level system schematic of cart-based SCISCCO prototype. Figure 22: Pictures of SCISCCO prototype: (**a**) isometric, (**b**) front, and (**c**) side views. A detailed block diagram of the optical system and hardware layout (i.e., the middle level of the cart) is provided in Figure 23. The output from the SC laser is coupled via a fiber into the NanoMax beam launcher. A turning mirror is used to direct the NanoMax output into an Acton 2150 spectrometer. The spectrometer output is then passed through a polarizer, and a wedged window is used to split the beam after the polarizer into a reference arm and a sample arm. The sample arm is coupled to a fiber to deliver to the target, and the return light is then collected and coupled through another fiber to the detector. The fibers in the reference arm to and from the target are 10 m in length and 2.5 mm in diameter. Figure 24 summarizes the measured performance metrics for the cart-based SCISSCO prototype. The SC laser was adjusted to a pulse repetition rate of 1 MHz, and the output pulse width was approximately 1.67 ns. The SC time-averaged laser output power was 5.15 W, and the back-reflection into the laser was measured to be 410 microwatts. The output from the fiber probe delivered to the target was 1.9 mW at a 900-nm wavelength and 0.44 W at a 800-nm wavelength. The SCISCCO system was tuned through the spectrometer between 780 nm and 900 nm, thus enabling the CCO and hemodynamic response measurements. All of the components in the SCISCCO prototype were mechanically secured to enable the cart unit to move in a lab or hospital setting as well as be transportable via a vehicle from one location to another. For example, the SCISCCO prototype was transported from the University of Michigan in Ann Arbor to Northwestern University Medical Center in Chicago for the animal testing (described further in the next section). To verify the stability of the SCISCCO system, we first rolled the cart system across brick hallways indoors and  
Figure 23: Detailed optical block diagram of optical system hardware (cart middle layer). Figure 24: Measured system performance parameters for cart-based SCISCCO prototype. measured the spectrum and SNR before and after the movement. For instance, Figure 25 illustrates the spectrum of the sample and reference arm (from Figure 24) before and after the shaking movement, where a polystyrene scattering medium was used in the sample arm for testing. In addition, the SNR of the sample arm, the reference arm, and the sample divided by the reference (the \"after cancellation\") are shown in Figure 26 before and after the movement.