**1. Introduction**

Capsule endoscopy was independently invented in the last decade of the 20th century by Ga‐ briel Iddan and Paul Swain. They both were committed to develop a wireless camera that would transmit images for the insides of the digestive tract to an extracorporeal receiver. They faced many significant challenges. The last hurdle to be taken was made possible by the miniaturization of the photosensitive chip (CMOS). This device transmits images in digi‐ tal format and is very economical with modest energy consumption. In this capsule the fol‐ lowing elements were implanted: a light source (LED), a lens, the photosensitive chip, a power source (batteries) and a transmitter with and antenna (see Figure 1).

In the year1996 the stomach of a pig was visualized by this method. The importance of this discovery remained as yet elusive to the medical community at large. Yet Paul Swain and Gabriel Iddan pursued their invention. Internal Review Board approval was obtained and the first human ingestion of a wireless capsule endoscope was performed by Paul Swain in Israel on October 17th 1999. In the year 2000 the scientific journal Nature realized that some‐ thing of importance was taking place and devoted an article to wireless capsule endos‐ copy[1]. The question had to be addressed whether capsule endoscopy was a cute high tech toy or whether this device had clinical importance for the medical community. The results of a double blind controlled study comparing capsule endoscopy to push enteroscopy (the best available method at that time) in patients with occult gastrointestinal bleeding were present‐ ed at the Digestive Disease Week meeting in Atlanta in the year 2001. Capsule endoscopy was superior to push enteroscopy at a rate of two to one[2]. A few months later the US Food and Drug Administration approved the use of capsule endoscopy. From there on capsule endoscopy has captured the field of small bowel endoscopy. Capsule endoscopy of the small bowel was superior to conventional methods in diagnosing NSAID induced enterop‐ athy, Crohn's disease of the small bowel, tumors of the small bowel and other diseases. Di‐ rect visualization of the gastrointestinal mucosa was superior to barium studies. For this

© 2013 N. Adler and Hassan; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

reason the gastroscope had replaced upper gastrointestinal series, the colonoscope had re‐ placed barium enemas and it was now the capsule endoscopy's turn to replace the small bowel follow through examinations.

bowel mucosa either in forward view if the capsule enters the small bowel with the camera end first or in backward view if the capsule enters with the transmitter end first. This is not true for the colon. In the large bowel with its wide diameter the capsule can tumble around its axis. A capsule with a single camera would screen certain areas twice and other areas not

Colon Capsule Endoscopy: Quo Vadis? http://dx.doi.org/10.5772/53055 245

The engineers solved this challenge by offering a colon capsule that has two cameras, one camera at each end. The colonic mucosa is visualized from both directions simultaneously.

The capsule transit time to reach the end of the colon is significantly longer than the time required for the capsule to reach the cecum and the colon capsule consumes more energy than the small bowel capsule since it transmits images from two cameras. Yet the energy

To reduce energy requirements the colon capsule was put to sleep for an hour and a half, five minutes after ingestion. This hour and a half of transmit time became now available for

The third hurdle is bowel cleansing. In standard colonoscopy some minimal amount of liq‐ uid debris can be aspirated, yet minimal amount of debris may compromise the capsule's

A more vigorous bowel preparation had to be offered to patients to assure proper cleansing

The first colon capsule was tested in the year 2005 and 2006[3]. The results of three studies were encouraging. Firstly the bowels could be adequately cleansed in 72 to 84% of patients. Secondly the capsule passed through the entire gastrointestinal tract while transmitting im‐ ages from the entire colon in 81% of patients within 8 hours. Finally the capsule did indenti‐ fy pathologies such as polyps, tumors, colitis, diverticulosis and internal hemorrhoids. Proof of principle had been obtained. However the sensitivity of 58 to 64% to identify patients with polyps equal to or larger than 6 mm as compared to standard colonoscopy was subop‐

The shortcomings of this first colon capsule were analyzed and the capsule underwent a thorough overhaul. The second generation colon capsule has the following improvements.

This guarantees complete visual coverage of the entire colonic surface.

at all. Solution:

**2.** Problem:

Solution:

**3.** Problem:

Solution:

supply is limited to two watch batteries.

ability to identify pathological findings.

timal and fell short of expectations [4].

**3. New features of colon capsule 2**

for colon capsule examinations.

transmission from the colon.

**Figure 1.** Optical dome, 2 Lens holder, 3. Lens, 4.Illuminating LEDs (light emitting diodes), 5. CMOS (Complementary Metal Oxide Semiconductor) image, 6. Battery, 7.ASIC (Application Specific Integrated Circuit) transmitter, 8. Antenna

Once capsule endoscopy had proven itself as a very useful and important diagnostic tool in the work up of small bowel disease, the concept of non invasive endoscopy sought expan‐ sion to other areas of the gastrointestinal tract as well. This chapter deals with capsule en‐ doscopy of the colon.

### **2. History of capsule endoscopy of the colon**

In contrast to capsule endoscopy of the small bowel, capsule endoscopy of the colon faces serious challenges for the following reasons.

#### **1.** Problem:

The small bowel is narrow (hence its name). As the capsule camera enters the small bowel it remains by and large fixed in its orientation and facing the same direction, either camera first or transmitter first. The capsule as a rule does not flip around its own axis. The capsule travels along its journey through the small bowel in the same orientation as it enters the small bowel. For this reason the single camera of the capsule will screen the entire small bowel mucosa either in forward view if the capsule enters the small bowel with the camera end first or in backward view if the capsule enters with the transmitter end first. This is not true for the colon. In the large bowel with its wide diameter the capsule can tumble around its axis. A capsule with a single camera would screen certain areas twice and other areas not at all.

#### Solution:

reason the gastroscope had replaced upper gastrointestinal series, the colonoscope had re‐ placed barium enemas and it was now the capsule endoscopy's turn to replace the small

**Figure 1.** Optical dome, 2 Lens holder, 3. Lens, 4.Illuminating LEDs (light emitting diodes), 5. CMOS (Complementary Metal Oxide Semiconductor) image, 6. Battery, 7.ASIC (Application Specific Integrated Circuit) transmitter, 8. Antenna

Once capsule endoscopy had proven itself as a very useful and important diagnostic tool in the work up of small bowel disease, the concept of non invasive endoscopy sought expan‐ sion to other areas of the gastrointestinal tract as well. This chapter deals with capsule en‐

In contrast to capsule endoscopy of the small bowel, capsule endoscopy of the colon faces

The small bowel is narrow (hence its name). As the capsule camera enters the small bowel it remains by and large fixed in its orientation and facing the same direction, either camera first or transmitter first. The capsule as a rule does not flip around its own axis. The capsule travels along its journey through the small bowel in the same orientation as it enters the small bowel. For this reason the single camera of the capsule will screen the entire small

bowel follow through examinations.

244 Colonoscopy and Colorectal Cancer Screening - Future Directions

doscopy of the colon.

**1.** Problem:

**2. History of capsule endoscopy of the colon**

serious challenges for the following reasons.

The engineers solved this challenge by offering a colon capsule that has two cameras, one camera at each end. The colonic mucosa is visualized from both directions simultaneously. This guarantees complete visual coverage of the entire colonic surface.

### **2.** Problem:

The capsule transit time to reach the end of the colon is significantly longer than the time required for the capsule to reach the cecum and the colon capsule consumes more energy than the small bowel capsule since it transmits images from two cameras. Yet the energy supply is limited to two watch batteries.

#### Solution:

To reduce energy requirements the colon capsule was put to sleep for an hour and a half, five minutes after ingestion. This hour and a half of transmit time became now available for transmission from the colon.

#### **3.** Problem:

The third hurdle is bowel cleansing. In standard colonoscopy some minimal amount of liq‐ uid debris can be aspirated, yet minimal amount of debris may compromise the capsule's ability to identify pathological findings.

#### Solution:

A more vigorous bowel preparation had to be offered to patients to assure proper cleansing for colon capsule examinations.

The first colon capsule was tested in the year 2005 and 2006[3]. The results of three studies were encouraging. Firstly the bowels could be adequately cleansed in 72 to 84% of patients. Secondly the capsule passed through the entire gastrointestinal tract while transmitting im‐ ages from the entire colon in 81% of patients within 8 hours. Finally the capsule did indenti‐ fy pathologies such as polyps, tumors, colitis, diverticulosis and internal hemorrhoids. Proof of principle had been obtained. However the sensitivity of 58 to 64% to identify patients with polyps equal to or larger than 6 mm as compared to standard colonoscopy was subop‐ timal and fell short of expectations [4].
