Flexible BronchoscopeFlexible BronchoscopeMedical Engineering, Faculty of Engineering,

The University of Hong Kong, HKSAR

Joanna Cheung Pui Ying 2004193805

Christine Ho Ka Man 2004032647

Veron Leung Ka Pik 2004125573

Eric Li Chun Hei 2004156871

Eyepiece

Control knob

Working channel

Video connection

Biopsy port with cap

Suction port

Insertion tube

Light source and camera

Light transmitting glass fiber bundle

Viewing glass fiber bundle

Fig. 1 Different parts of flexible bronchoscope [1]

There are two types of flexible bronchoscope: There are two types of flexible bronchoscope: fiberoptic bronchoscope and videobronchoscope. fiberoptic bronchoscope and videobronchoscope. The former one was firstly introduced in 1960’s The former one was firstly introduced in 1960’s and the latter one was developed in 1990’s.and the latter one was developed in 1990’s.

The exit angle will The exit angle will then approach then approach 90° for some 90° for some critical incident critical incident angle angle θθc, and for c, and for incident angles incident angles greater than the greater than the critical angle critical angle there will there will be total internal be total internal reflectionreflection[2][2] (see (see fig. 3).fig. 3).In flexible bronchoscope, light is delivered In flexible bronchoscope, light is delivered distally by total internal reflection. (see fig. 4)distally by total internal reflection. (see fig. 4)

For fiberoptic bronchoscope, images are For fiberoptic bronchoscope, images are brought back to eyepiece using this principle, brought back to eyepiece using this principle, too.too.

For videobronchoscope, images are brought For videobronchoscope, images are brought back by a small charge-coupled device (CCD) back by a small charge-coupled device (CCD) sensor in the tip part. Better image resolution sensor in the tip part. Better image resolution can be obtainedcan be obtained[3][3]..

Introduction to Flexible Introduction to Flexible BronchoscopeBronchoscope

In the diagnosis of pulmonary diseases, In the diagnosis of pulmonary diseases, radiography is usually used to identify the radiography is usually used to identify the problems. However, sometimes there maybe problems. However, sometimes there maybe cases that chest x-ray or thoracic CT scan give cases that chest x-ray or thoracic CT scan give us unclear or wrong information. In order to us unclear or wrong information. In order to improve the accuracy of diagnosis, bronchoscopy improve the accuracy of diagnosis, bronchoscopy is applied to identify the diseases and flexible is applied to identify the diseases and flexible bronchoscope is commonly used (see fig. 1). bronchoscope is commonly used (see fig. 1).

Working principle of bronchoscope Working principle of bronchoscope

Transmission of light in bronchoscope is based on Transmission of light in bronchoscope is based on total internal reflection.total internal reflection. When light is incident When light is incident

upon a medium of lesser upon a medium of lesser index of refraction (ni>nt), index of refraction (ni>nt), thethe ray is bent away from ray is bent away from the normal such reflectionthe normal such reflection

is commonly called "internal reflection"is commonly called "internal reflection" (see fig. 2) (see fig. 2)..

Fig. 3 Total internal reflection[2]

Fig. 5 A flexible bronchoscope is used to view the airway of the patient[4]

Application of flexible Application of flexible bronchoscopebronchoscope

For diagnostic purpose:For diagnostic purpose:1.1. To visualize and to observe the lesions of To visualize and to observe the lesions of

the tracheobronchial treethe tracheobronchial tree2.2. To collect specimen for biopsy and culture To collect specimen for biopsy and culture

(e.g. by curettage or brushing) (see fig. 6)(e.g. by curettage or brushing) (see fig. 6)

For therapeutic purpose:For therapeutic purpose:

1.1. To remove foreign body in the To remove foreign body in the tracheobronchial tree by forceps or baskets tracheobronchial tree by forceps or baskets (see fig. 7)(see fig. 7)

2.2. To remove malignant tumors by laserTo remove malignant tumors by laser (e.g. laser photoresection) (e.g. laser photoresection)

3.3. To frozen surface skin lesionsTo frozen surface skin lesions (e.g. (e.g. cryotherapy)cryotherapy)

4.4. To destroy malignant tumors by radiation To destroy malignant tumors by radiation (e.g. brachytherapy), by electricity (e.g. (e.g. brachytherapy), by electricity (e.g. electrocautery) or by chemicals (e.g. electrocautery) or by chemicals (e.g. photodynamic therapy)photodynamic therapy)[3][3]

Fig. 6a Brush used for collecting cells from tracheobronchial tree Fig. 6b Collecting cells by brushing[5]

6a 6b

Fig. 7 Forceps for removing foreign body in the bronchus[6]

Procedure of BronchoscopyProcedure of Bronchoscopy

1.1. Anesthetize the patient. Anesthetize the patient.

2.2. Inject a small amount of saline. Inject a small amount of saline.

3.3. Insert the bronchoscope through the nasal Insert the bronchoscope through the nasal cavity (see fig. 5).cavity (see fig. 5).

Fig. 4 Transmission of light within a optical fibre[2]

Fig. 2 Internal reflection[2]

Analysis of flexible Analysis of flexible bronchoscopebronchoscope

Fig.8 The turning degree of a bronchoscope[8]

Fig.9 The large set of monitor[10]

Overall, flexible bronchoscope is useful despite the disadvantages it has. It helps the doctors in Overall, flexible bronchoscope is useful despite the disadvantages it has. It helps the doctors in visualizing the tracheobronchial tree and this allows a better diagnosis for pulmonary diseases. In visualizing the tracheobronchial tree and this allows a better diagnosis for pulmonary diseases. In addition, operations can be carried out through flexible bronchoscopyaddition, operations can be carried out through flexible bronchoscopy . .

Further development of flexible Further development of flexible bronchoscopebronchoscope

1.1. Internal recording deviceInternal recording device

• Allow the bronchoscopist to check the Allow the bronchoscopist to check the previous findings and operations.previous findings and operations.• Enhance patient management.Enhance patient management.

2.2. More portable systemMore portable system• Install more portable components, say a Install more portable components, say a smaller LCD monitor and a smaller image smaller LCD monitor and a smaller image processing machine. (see fig. 10)processing machine. (see fig. 10)

Fig. 10 A smaller LCD monitor is more portable and convenient.[11]

3.3. Autofluorescence bronchoscopyAutofluorescence bronchoscopy

• Make use of the characteristics of Make use of the characteristics of autofluorescence on tumor to observe autofluorescence on tumor to observe carcinoma or dysplasia using special light carcinoma or dysplasia using special light source and equipmentsource and equipment[12][12] (see fig. 11). (see fig. 11).

11a 11b

Fig. 11a White light image. No abnormal area visible. Fig. 11b Autofluorescence image. Suspicious lung tissue with significantly reduced fluorescence.[13]

AcknowledgementAcknowledgementss

We thank Dr. Ian Gibson and Dr. Nelson Yung for giving the engineering information and Ms. Miranda Legg for the audio assistance. Special thanks to Dr. David Chong for showing us the demonstration of using flexible bronchoscope.

ReferencesReferences

[1] Emidicine consumer health website. Available at: http://www.emedicinehealth.com/. Accessed February 28, 2005.[1] Emidicine consumer health website. Available at: http://www.emedicinehealth.com/. Accessed February 28, 2005.[2] HyperPhysics Concepts website. Available at: http://hyperphysics.phy-astr.gsu.edu/. Accessed March 1, 2005. [2] HyperPhysics Concepts website. Available at: http://hyperphysics.phy-astr.gsu.edu/. Accessed March 1, 2005. [3] Bolliger C.T., Mathur P.N., ed. Interventional Bronchoscopy. Basel: Karger; 2000.[3] Bolliger C.T., Mathur P.N., ed. Interventional Bronchoscopy. Basel: Karger; 2000.[4] Your Medical Source website. Available at: http://yourmedicalsource.com/. Accessed February 28, 2005.[4] Your Medical Source website. Available at: http://yourmedicalsource.com/. Accessed February 28, 2005.[5] Tobacco Facts website. Available at: http://www.tobacco-facts.info/. Accessed March 1, 2005.[5] Tobacco Facts website. Available at: http://www.tobacco-facts.info/. Accessed March 1, 2005.[6] Untitled. Available at: http://www.hyunjoo.co.kr/. Accessed February 28, 2005.[6] Untitled. Available at: http://www.hyunjoo.co.kr/. Accessed February 28, 2005.[7] Beamis J. F. Jr., Mathur P.N.. Interventional Pulmonology. The United States of America, the McGraw-Hill Companies, [7] Beamis J. F. Jr., Mathur P.N.. Interventional Pulmonology. The United States of America, the McGraw-Hill Companies, Inc.; 1999.Inc.; 1999.[8] Karl Storz Veterinary Endoscopy America Inc. website. Available at: http://www.karlstorz.com/. Accessed March 1, 2005.[8] Karl Storz Veterinary Endoscopy America Inc. website. Available at: http://www.karlstorz.com/. Accessed March 1, 2005.[9] Cladonia Resources website. Available at: http://www.cladonia.co.uk/. Accessed March 2, 2005.[9] Cladonia Resources website. Available at: http://www.cladonia.co.uk/. Accessed March 2, 2005.[10] Beth Israel Deaconess Medical Center. Available at: http://bidmc.harvard.edu/. Accessed February 28, 2005. [10] Beth Israel Deaconess Medical Center. Available at: http://bidmc.harvard.edu/. Accessed February 28, 2005. [11] LUXMA Manufacturer of Mobile Accessories website. Available at: http://www.luxmt.com/. Accessed March 1, 2005.[11] LUXMA Manufacturer of Mobile Accessories website. Available at: http://www.luxmt.com/. Accessed March 1, 2005.[12] J.A. Nakhosteen, B. Khanavkar. Autofluorescence Bronchoscopy: The Laser Imaging Fluorescence Endoscope. In: [12] J.A. Nakhosteen, B. Khanavkar. Autofluorescence Bronchoscopy: The Laser Imaging Fluorescence Endoscope. In: Bolliger C.T., Mathur P.N., ed. Interventional Bronchoscopy. Basel: Karger; 2000:236-242.Bolliger C.T., Mathur P.N., ed. Interventional Bronchoscopy. Basel: Karger; 2000:236-242.[13] American College of Chest Physicians website. Available at: http://www.chestnet.org/. Accessed February 28, 2005.[13] American College of Chest Physicians website. Available at: http://www.chestnet.org/. Accessed February 28, 2005.

Pros of flexible bronchoscopePros of flexible bronchoscope Cons of flexible bronchoscopeCons of flexible bronchoscope Small and maneuverableSmall and maneuverable[7][7]

- Easier to insert to the distal airway - Easier to insert to the distal airway - More comfortable for the patient- More comfortable for the patient (see fig. 8)(see fig. 8) Distal biopsy is easyDistal biopsy is easy Provide a better diagnosis than CT scan and X-Provide a better diagnosis than CT scan and X- rayray Many doctors can see the screen at the same Many doctors can see the screen at the same timetime

Difficult to keep the lens visualizingDifficult to keep the lens visualizing [7][7]

Glass fiber is prone to damageGlass fiber is prone to damage[9][9]

No internal recording system is availableNo internal recording system is available Need anestheticNeed anesthetic

- May lead to allergy - May lead to allergy Nose bleedingNose bleeding The surgeon cannot look at the patient and the The surgeon cannot look at the patient and the screen at the same timescreen at the same time Link to a large set of monitor Link to a large set of monitor (see fig. 9)(see fig. 9) Maintenance is expensiveMaintenance is expensive