The authors would like to thank all the bronchoscopists at the Department of Respiratory Medicine, Odense University Hospital, for providing images for the article.

The protocol in this article describes standard clinical practice. No permission from the ethical&#160;committee was needed. Images in the protocol contain no information which can be used to&#160;indentify patients.
1. Radial endobronchial ultrasound
<ol>
	<li>Preparing for the procedure
	<ol>
		<li>Examine the CT scan to check for bronchus signs and the location of the lesion before the procedure.</li>
		<li>Calibrate the ultrasound probe, guide sheath, and biopsy tools of...

This article presents a practical approach for performing rEBUS and ENB with fluoroscopy. The following discussion is the opinion of the authors and is based on practical clinical experience from two centers.
Tips and tricks 
rEBUS 
Before the procedures the Chest CT sectional walker app can be used to check in which segment the lesion is located14. However, since the anatomy of patients differs, the lesion may be located in a...

Lung cancer is one of the most common cancer types worldwide and the leading cause of cancer-related deaths1. Screening for lung cancer with low-dose computed tomography (CT) has therefore been suggested to diagnose patients before symptoms occur2. Low stages are often detected as small lung lesions or nodules. From one of the largest screening studies conducted in the Netherlands, we know that these lesions are often located in the outer 2/3 of the lung parenchyma and are thereby defined as peripheral lung cancers3,4. To determine whether a lesion is malignant, a tissue sample is required. This can be obtained in several different ways such as surgical excision biopsy, trans-thoracic needle biopsy, or endoscopic with a bronchoscope5,6, the latter having a lower risk of complications compared to surgery and the trans-thoracic approach and a preferable method for diagnosing an increasing elderly population with considerable comorbidities. The diagnostic yield, however, is still lower than the other modalities5.
The bronchoscope allows for visual inspection of the trachea and the main bronchi, but when the bronchi branch into segments and subsegments, locating one small lesion is comparable to finding a needle in a haystack. Therefore, several additional modalities have been developed to guide the bronchoscope to the lesion and confirm the location of a tumor before tissue sampling7. The purpose of these modalities is to increase the diagnostic yield of endoscopic tissue sampling and expand the reach of the bronchoscope towards the pleura, where trans-thoracic needle biopsies are otherwise performed8,9.
Fluoroscopy using a C-arm provides a 2D X-ray image of the thorax during bronchoscopy. It can be used to visualize the position of the bronchoscope and the forceps for trans-bronchial biopsies (TBB) to avoid sampling the pleura and the vascular structures of the intermediate 1/3 of the lung parenchyma when performing random TBBs. When diagnosing lung cancer, fluoroscopy can be used to guide the scope to an &#34;approximate&#34; location of the lesion. Lesions are usually visible on fluoroscopy when the diameter is around 2-2.5 cm or above10. The drawback of fluoroscopy is the 2D image properties, which makes it impossible to know whether the scope is in front, behind, or the center of the lesion11. However, fluoroscopy is also used to confirm that the biopsy tools are in the desired location during sampling if the presence of a tumor has been confirmed with radial endobronchial ultrasound (rEBUS)12.
rEBUS was first described in 1992 by H&#252;rter et al. and is increasingly used in diagnostic workup of peripheral lung lesions13. This modality utilizes the fact that the air-filled lung tissue does not conduct ultrasound waves, whereas denser tissue will appear as a consolidation when scanned using an ultrasound probe. rEBUS is comprised of a circular and rotating ultrasound probe, an ultrasound driving unit, and a guide sheath used to protect the probe while ensuring the correct position of the biopsy tools14. rEBUS can be used on its own or together with other modalities such as electromagnetic navigation bronchoscopy (ENB)15,16,17.
ENB is used to locate a peripheral lung lesion18. The system uses a software program and a CT scan from the patient. A virtual model of the patient&#180;s airways is generated from the CT scan and the operator designs a route from the trachea to the lesion. An electromagnetic field is then created around the patient&#180;s chest and the software synchronizes this field with the virtual field generated from the CT scan, thus assisting the operator to follow the preplanned route during the bronchoscopy, similar to Global Positioning System technology. ENB does not provide real-time confirmation of tumor location. ENB can be combined with fluoroscopy and rEBUS19,20. Virtual Navigation Bronchoscopy (VBN) is the predecessor to ENB and consists of software for creating the virtual model of the bronchial tree along with a route to the lesion. The system does not include real-time navigation, but the route can be displayed during the bronchoscopy21,22. New systems incorporate VBN with fluoroscopy but the use of VBN will not be described in the following protocol23.
ENB systems 
Currently, two companies produce systems for ENB, the SPiN&#160;system from Olympus and the superDimension system and the ILLUMISITE both sold by Medtronic. The protocol will describe a procedure using the superDimension system, which currently has the most publications. However many steps of the procedure are interchangeable.
The following protocol will describe how to perform rEBUS under fluoroscopy and ENB + rEBUS under fluoroscopy in a clinical setting. The procedures can easily be performed under conscious sedation and general anesthesia. The protocol will not describe any methods for sedation. In the discussion section, the pros and cons of each procedure will be presented.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bronchoschope</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Edge Extended working channel</td>
			<td>Medtronic&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Edge locatable guide</td>
			<td>Medtronic&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Guide sheath kit</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>OEC fluorostar</td>
			<td>GE healthcare</td>
			<td></td>
			<td>C-arm for fluoroscopy&#160;</td>
		</tr>
		<tr>
			<td>Probe Driving Unit&#160;</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Radial EBUS probes</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>superDimension</td>
			<td>Medtronic&#160;</td>
			<td></td>
			<td>Navigation system</td>
		</tr>
	</tbody>
</table>

radial endobronchial ultrasound and electromagnetic navigation bronchoscopy with fluoroscopy for the diagnosis of peripheral lung lesions

Diagnosing lung cancer using a flexible bronchoscope is a safe procedure with a very low risk of complications. Bronchoscopy has high diagnostic accuracy for endobronchial lesions, but it falls short when sampling peripheral lesions. Therefore, several modalities have been invented to guide the bronchoscope to the lesion and confirm the location of the tumor before tissue sampling. 
Fluoroscopy is used during bronchoscopy to provide a 2D X-ray image of the thorax during the procedure. The bronchoscope and tools will be visible, as well as lesions if larger than 2.0-2.5 cm. Radial endobronchial ultrasound (rEBUS) consists of an ultrasound probe, small enough to be inserted into the working channel of the bronchoscope. The ultrasound probe is used to differentiate between consolidated tissue, such as tumor tissue, and normal air-filled lung parenchyma. Electromagnetic navigation bronchoscopy (ENB) creates a 3D model of the bronchial tree from computed tomography (CT) scans of the patient. Prior to the bronchoscopy, a route from the trachea to the lesion is planned, to create real-time guidance of the bronchoscope to the lesion during the procedure, similar to the Global Positioning System. The aim of this article is to describe a stepwise approach to performing bronchoscopy with rEBUS and fluoroscopy, bronchoscopy with ENB, rEBUS, and fluoroscopy. In the discussion section, the pros and cons of each modality will be discussed.

The described technique facilitates the sampling of peripheral lung lesions. Radial EBUS and fluoroscopy will aid the bronchoscopist in confirming the presence of a lesion before sampling the tumor (see Figure 1 and Figure 2). By adding ENB, the bronchoscopist is guided to the correct spot instead of searching for the lesion. The planning phase provides the bronchoscopist with a route to the lesion, real-time guidance to the lesion with the navigation system, co...

Read this Scientific Article Protocol about Radial Endobronchial Ultrasound and Electromagnetic Navigation Bronchoscopy with Fluoroscopy for the Diagnosis of Peripheral Lung Lesions at JoVE.com

Radial Endobronchial Ultrasound and Electromagnetic Navigation Bronchoscopy with Fluoroscopy for the Diagnosis of Peripheral Lung Lesions

Diagnosing small lung tumors is quite difficult using a bronchoscope alone. Electromagnetic navigation bronchoscopy is used to locate the lesion, similar to the Global Positioning System. Radial endobronchial ultrasound and fluoroscopy confirm the correct location and monitor the sampling.

Diagnosing lung cancer using a flexible bronchoscope is a safe procedure with a very low risk of complications. Bronchoscopy has high diagnostic accuracy ...