Interactive seminar on the development of an EMP textbook

J. Patrick Barron
International Medical Communications Center
Tokyo Medical University

19 May 2004

We are currently developing texts for teaching medical school students and beginning translators. We have made a sample text on endoscopy (pasted below) and would like your comments as follows.

  1. Do you find it useful for a translator as a background to endoscopy?

  2. What vocabulary should be given in Japanese in a glossary?

  3. What points should be added?

  4. What points should be eliminated?

  5. What kind of questions would be suitable to test understanding? (Please think of 5, in either language.)

Endoscopy: From the outside, looking in

As the etymology of the word 'endoscopy' suggests, it is the study, or viewing, of the inside of the human body. Endoscopy is a very common medical examination procedure and many of us do not think of it as anything special, but endoscopy today involves a wide range of extremely highly developed technology that permit visualization of the internal aspects of many organs of the body, and even within blood vessels. It is therefore important to realize how the endoscope was developed and to have an understanding of the extremely varied range of both diagnostic and therapeutic usage of the technology. Originally, the majority of endoscopy techniques were for visual observation and simple biopsies, that is the collection of tissue for examination under a microscope. However it has other uses for diagnostic and therapeutic application not only in cases of inflammation, ulcers etc. but also cancer, and it can also enable highly sophisticated surgical techniques that minimize the amount of surgical invasion into the human body.

There are reports of instruments discovered in Pompeii that indicate that perhaps Roman doctors might have used tubes to look into the throats of some patients. The first historically recorded endoscope was developed 200 years ago, in 1804, by a German called Bozzini. The only light source available at that time was a candle, so he devised a tube at the aperture of which there was a metal plate dividing the area looked through by the examining doctor or endoscopist, and on the other side of the plate was the candle with a mirror placed behind it to try to double the illumination. He used this to examine the rectum, urethra and vagina. When he developed this two centuries ago, there were many problems caused by the heat generated by the candle and some patients suffered burns. (Fig. 1)

A little more than half a century later, the development of the incandescent lamp by Edison immediately suggested to many people the possibilities of the application of this invention for medical applications. Very soon a miniaturized version of Edison's incandescent lamp was used to try to develop an instrument that could be used to look inside the human throat and esophagus. In 1918, an arthroscope, that is an endoscope that could be used to examine large joints, such as the hip, was developed by Dr. Watanabe in Japan, and this was used to view large joints such as the hip. Various developments in optical engineering made it possible for images to be reflected through articulated endoscopes (rigid, jointed) and this led to the so-called 'semi-flexible gastroscope' in Germany in 1932 made by Dr. Schindler.

However the modern era of endoscopy is really most closely related to fiberoptic endoscopy, and the first step towards that was the gastrocamera which was developed in 1952 by Olympus in Japan, followed by the fiberoptic flexible gastroscope in the U.S. in 1957. Since the semi-flexible rigid gastroscope had restrictions in terms of the range of view within the esophagus and stomach, the gastrocamera was developed in order to overcome those restrictions. It was basically a small camera at the end of a flexible tube that could be turned around under x-ray observation to make it point at what the operator thought was the main target area. With this system, the internal area of the stomach was photographed while controlling the direction of the camera under x-ray guidance. Of course it was only possible to find out the appearance of the photographed areas later after the camera was removed and the film was developed, therefore real-time examination was not possible. This was a huge development in terms of being able to photograph the area of interest to the gastroenterologist. However sometimes it was found that the camera had not been pointed at the target area at all, and the procedure had to be repeated.

The major event after the miniaturization of the Edison light bulb and the camera was the development of flexible fiberoptic fibers, which made it possible to not only deliver light to the target area but also to deliver the illuminated image back to the eye or the camera of the examiner. The development of the fiberoptic light and image transmission meant that there was no need for a light bulb at the tip of the endoscope: the light could be projected through the light guiding fibers of the endoscope. This was supplied by what is called a cold light supply. In other words the heat from the light was removed before transmission through the fiberoptic bundles. Then a cable of fiberoptic bundles was used to transmit the light from the light source through the fiberscope through its tip. This is called a light guide. The development of this technology meant that there was no danger of burns caused by heat from the light bulb because there was no heat from the cold light and there were also no problems with the light bulb ceasing to function in the middle of procedures and requiring immediate replacement. (Fig. 2)

The image guide is a bundle of fiberoptic fibers that joins the lens at the tip of the fiberscope and the lens in the handheld control set used by the endoscopist. The image seen at the tip of the fiberscope is transmitted through these fibers, which is why it is called the image guide. The thickness of each fiber bundle is extremely small, about one tenth of the thickness of a human hair. The handheld control unit has either levers or rotatable knobs which are connected through the inside of the instrument to the tip by wires. Their manipulation controls the direction in which the tip points. In addition, many endoscopes have an empty channel that allows the passage of various instruments to either collect materials for diagnosis or to perform treatment procedures. This channel is known as the working channel or the biopsy channel or the instrumentation channel.

It is now possible for endoscopes to be inserted into almost all hollow organs such as the trachea and bronchi, the esophagus, stomach, duodenum, rectum, large intestine, small intestine, cecum, etc. and now there are some ultrathin fiberscopes that allow passage to very peripheral areas of the tracheobronchial tree in the lungs and even to be passed through blood vessels to examine any obstruction or blockage.

About 20 years ago, in the early 1980's, the fiberoptic bronchoscope was significantly affected by the emergence of the video technology that made electronic videoendoscopes possible. This instrument, instead of passing an image along the body of the endoscope had a tiny videocamera located at the tip of the endoscope which converted the image from an optical image into a transmitted electronic signal. While originally monochrome components (charge-coupled devices, CCDs) were used because of a larger CCD was necessary for color, at present almost all electronic videoendoscopes are color instruments. The image is separated into red, blue, green sequences by means of a rotating filter and same sequences is maintained in the acquisition of the image by the CCD. Image reconstruction and analysis is performed by video processor, which then electronically passes the image onto the monitor. (Fig. 3)

The CCD chip technology in the electronic videoendoscope avoids having to pass the image through a fiber medium and therefore provides an extremely clear, high-resolution image. Its ability to process images digitally opens up new doors in the world of endoscopic examinations and digital storage of information. Concerning the digital storage of information, the electronic signal of the electronic videoendoscope can be stored on not only optical memory devices such as laser disks and 35 mm film, as well as hardcopy, but also floppy disks, videotapes, magneto optical disks, clip drives etc. (Fig. 4)

One other feature distinguishing the electronic videoendoscope from the preceding fiberoptic endoscope is that the screen on the monitor of the electronic endoscope usually consists of a main image and a smaller subscreen in the corner of the main image screen. This means that the endoscopists can freeze an image if they want to look at it in closer detail. When this happens, the main screen shows the frozen image while the subscreen shows the continuing real-time endoscopic findings. If the endoscopist wants to record the frozen image or the moving image, that is easily accomplished by pressing the control unit button. Comments made by the endoscopists can also be combined with the image to facilitate later discussions among staff or even in making explanations to patients about their condition.

The increased flexibility of the fiberoptic endoscope and later the electronic video endoscope compared to previous semi-rigid or rigid instruments meant that, especially as the range of accessory equipment to be used with the endoscope became increasingly versatile, endoscopy moved slowly from being a primarily diagnostic procedure to diagnosis plus treatment.

One of the earliest forms of treatment using endoscopes was the removal of foreign bodies. In the airways, especially children around the age of 2 are liable to put things in their mouth and can aspirate them by accident. In such cases, endoscopy can allow rapid removal and almost instantaneous relief. For this purpose, the range of forceps to grasp various kinds of material aspirated by patients from peanuts to coins to pen caps, even to false teeth were developed. (Fig. 5)

In the 1970's one of the first accessory instruments developed not only for diagnostic but also therapeutic means was the retractable needle developed at Tokyo Medical University Department of Surgery. The needle was at the tip of a long thin tube. First of all the needle was retracted inside the tube to avoid any damage to the walls of the endoscope, then the thin tube was inserted through the endoscope, still keeping the needle tip retracted. After the thin tube containing the needle is passed through the working channel of the endoscope and emerges from the tip into the visual field of the lens at the tip of the scope, the site for insertion of the needle is selected and then the tip of the needle is projected from the covering of the thin tube. (Fig. 6) This retractable needle has several uses. It can be used to inject anticancer agents directly into tumors, or, it can be used to puncture beyond the wall of the bronchus to suction material such as cells from lymph nodes that cannot be obtained directly by biopsy in order to determine whether a cancer has spread to that lesion or not. Whether there is spread of cancer cells to lymph nodes or not can significantly affect the type of treatment that is most appropriate for that patient. Therefore it is essential to obtain materials that can be directly visualized such as cells or tissue rather than relying purely on diagnostic imaging such as x-ray films and CT images etc.

Yet another application of the retractable needle is to inject materials that cause cancer, carcinogenic substances, into the bronchial walls of animals with large airways, in order to see how repeated injections of cancer causing substances affect the bronchial wall and how cancer slowly develops. While there are many kinds of experiments to produce cancer in smaller animals such as mice or rats, the advantage of using larger animals is that the airways are large enough to permit endoscopic observation of any changes at the injection site.

As mentioned earlier, a wide range of instruments has been developed to be used with endoscopes. These include forceps to grasp foreign bodies or remove tissue for diagnosis, a stapler that can be used to stop bleeding, sutures that can be used to cut through surgically placed sutures and then remove them, fibers that can pass laser beams of varying strengths and wavelengths depending on the purpose and a probe that can send a powerful electrohydrolic shockwave to explode stones located in the ureters, the passages between the kidneys and the bladder. There are also many instruments that can be used with electrical power for electrosurgery. These include a wire snare, which is like a loop of wire which is placed around a polyp. The loop is then gradually tightened and finally electrical power is passed through, using alternating blood coagulating and tissue-cutting current so that, as the tissue is cut, bleeding is also halted. (Fig. 7)

Among the lasers mentioned above the neddymouth, yttrium, aluminum garnet (NdYAG) lasers can be used at various power levels to either induce tissue regeneration or to cut through tissue depending on the wavelength and other laser beams can be used at low power but with a specific wavelength to trigger activity by a drug that has been previously injected into the body of a cancer patient. This drug is then taken up by the cancer lesion but is not retained by normal tissue. The triggering effect of the laser passed through a fiber inside the working channel of the endoscope can then stimulate the drug to produce singlet oxygen, causing the cancer cells in which the drug is taken up to die. This so-called photodynamic therapy has been used with endoscopes increasingly in the last 20 years, ever since its first application through an endoscope at Tokyo Medical University.

In the photodynamic therapy (PDT) procedure the drug is given 24 to 72 hours before the endoscopy. By that time most of the drug has drained from normal tissue but is retained in the active growing tissues such as the tumor, and the low-level power light from the laser at a specific wave length of 630 nm stimulates the drug, causing the above mentioned cell-killing effect.

Endoscopy is also being used with other techniques such as ultrasonography. In this method there is a small ultrasonographic equipment is embedded in the tip of the fiberscope so that the operator can see not only the surface findings of the mucosa of, for example the esophagus, but also with the ultrasound image, is able to understand the situation beyond the visibly recognizable wall of the esophagus up to a depth of about 1 cm. These images also provide information about the conditions and size and of lymph nodes.

Recently there have been articles in various journals and newspapers about capsules endoscopes. These are capsules containing the endoscope which are swallowed and passed through the gastrointestinal system which the direction of the capsule is controlled by magnets placed outside the body and the capsule either takes photographs or relays the visual information to the monitor outside the body.

With recent tremendous advances in the field of robotics, it would not be very farfetched to imagine the next step in endoscopy, that of robotic endoscopy. Whatever the future of endoscopy may hold, it is certain to be very exciting and very useful for the prevention, diagnosis and treatment of a wide range of diseases.

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