distance between the LG and the targeted lesion in millimeters (mm). Once the LG reaches the desired target location, the EWC is xed at the proximal end of the biopsy channel of the bronchoscope by a special locking mechanism and the LG is withdrawn. Bronchoscopic biopsy tools such as biopsy forceps, transbronchial aspiration needle and endobronchial brush can be inserted via the EWC to obtain a tissue specimen. The bronchoscopists may then biopsy at this location. However, there is no further guidance from the navigation system once LG is withdrawn. In addition, the biopsy tools may miss the target due to catheter-to-nodule defection as EWC curve returns after removal of LG [17]. To compensate with this shortcoming, other imaging modalities are useful to guide the biopsy tools to maintain a precision during the biopsy.

Fluoroscopy can be performed to con rm the biopsy tools in the desired location before performing biopsy. Cone-beam CT (CBCT) is another novel tool to be used to con rm the location of biopsy tool. The fuoroscopy unit uses a fexible C-arm, which is lower in power and radiation exposure to the bronchoscopists and the patients. CBCT scans images in a cone shape rather than fan shape as in traditional CT [18]. Lastly, an rp-EBUS probe can also be inserted for additional location con rmation. Rp-EBUS is a thin, fexible catheter with a rotating ultrasound transducer that creates a 360-degree “radial” image. This device allows for a real-time localization of lesions that are located distally to the tip of the bronchoscope.

SPiN System Veran Medical Technologies (EMN-VM)

The SPiN System uses an always-on tipped track technology. The sensor tracking is built into the biopsy instruments allowing for real time navigation of the biopsy tools (Fig. 24.8). There are two additional features of the SPiNView system: (1) it incorporates a transthoracic needle system to biopsy lesions similar to CT-guided transthoracic needle aspiration (TTNA); (2) The SPiNView offers the respiratory tracking technology that monitors patient respiration during the procedure. Respiratory motion can be a problem dur-

Fig. 24.8  The main processor of the SPiN System® Veran Medical Technologies

ing TBBx because an average motion of pulmonary lesions has shown to be approximately 17.6 mm. With this much respiratory motion it may affect the diagnostic yield of EMN-guided TBBX or any other lung biopsy procedures [19]. Therefore, SPiN system develops pre-procedural virtual maps built off a CT closer to physiological lung volumes based on both inspiration and expiration CT scan (Fig. 24.9). During the airway inspection, SPiN system tracks the sensor probe to collect 3D points that are reconstructed into the lumen registration map. It predicts SPN location on a virtual inspiration and expiration map which is compared with lumen registration. A study found that predicted SPN location with expiration CT scan is signi cantly closer to actual nodule location (4.5 mm for expiration vs. 14.9 mm for inspiration) [20].