DOI 10.1007/s11082-005-9224-9
The concept and prototype system of medicine-jet
capsule endoscope
c h i n g - l o n g c h i u∗ a n d c h i n - t a i c h e n
Opto-Electronics Research & Service Center, Industrial Technology Research Institute South, No. 8, Gongyan Road, Liujia Shiang, Tainan County, Taiwna 73445, R.O.C.
(∗author for correspondence: E-mail: [email protected])
Received 1 February 2005; accepted 15 September 2005
Abstract. The wireless capsule is felt more comfortable for the patients than the traditional endoscope or enterscope. The wireless capsules, such as Heidelberg capsule, pH capsule or M2A capsule, have been successfully used as diagnostic tools for many years. This present paper proposes a new prototype system of the functional capsule endoscope that can bring and jet medicine to the nidus. The prototype system is comprised of an image sensor, illumination sources, microlenses, a two-way wireless module, medicine-jet subsystem and so on.
Key words: Capsule Endoscope, Medicine-jet, inkjet
1. Introduction
In the medical field, several types of miniaturized wireless capsules have been successfully developed for many years. For example, M2A capsule en-doscopes can take pH, temperature, motility and pressure measurement in the intestine and send biomedical video signal or measured data from inside the human body (Park et al. 2002). The capsule with size of 11 mm in diameter and 30 mm in longitude (i.e., about the size of a pill) provides an
in vivo images inside human body at a rate of two frames per second. These
video images are transmitted by using UHF-band to eliminate the problems related to fiber-optical endoscopes. Miniaturized capsule eliminates patient discomfort and the limitations into the small bowel. However, the M2A capsule only uses as the image sensor to search for the nidus, and sends the wireless image data to the recorder outside the body. If the capsule can further carry the drugs to the intestine and jet to the nidus, it is promoted to own medicine treatment.
2. The description and test of the system
There are five parts in the present system, which includes an imager, a wire-less module, a post-processor, a medicine-jet module and a supply module.
1448 C.-L. CHIU AND C.-T. CHEN 2.1. imager and wireless module
The video imager is mainly comprised of light sources, microlenses, an image sensor, an encoder and a receiver. Its basic goal is to take the contin-uous images from the image sensor. The light source could supply the light to illuminate the inner surface of the digestive tract and the microlens then focuses the reflected light onto the image sensor. Since the image signal from image sensor would be received in a large bitmaps format, the encod-ing procedure could be necessary. The schematic diagram of the imager and wireless module, is shown in Fig. 1. The proposed schematic diagram is composed of a CMOS image sensor, FPGA, wireless transceiver mod-ule, and a PC with DIO card. An in vivo imager may capture images of a body lumen and transmit the images to an external receiving module. In the present work, a CMOS image sensor (ElecVision 2003) from ElecVi-sion is selected. The control circuit includes the timing and logic circuitry. The FPGA may include a timing block for communicating with the image sensor, encoder, decoder and control block for controlling the medicine-jet. Signal can be received from the pixel array. The timing diagram for pixel data readout is presented in Fig. 2. The readout of individual pixels typi-cally begins from the dark period and follows with an exposure period.
The task of the wireless module is to transmit and receive the image data through the human body. The body is largely composed of water, which absorbs electromagnetic waves (Ahmadian et al. 2003). The absorp-tion is higher when the carrier frequency is higher. However, the lower frequency has slower data rate, the transceiver module (RFWaves 2003) of RFwaves is selected to ensure higher data transfer rate. The transceiver
Fig. 2. Schematic diagram of timing signal for pixel data readout.
vides data rate transfer of up to 1 Mb/s and modulation scheme is 100% Amplitude Shift Keying (ASK). The transceiver is intended for use in the world wide unlicensed industrial scientific and medical (ISM) band of 2400– 2483.5 MHz.
The Manchester Encoding technique is adapted for the image data communication. The advantage of this method is a simple clock extraction circuit that can be optimized for synchronous system (Popescu et al. 1995). The penalty is an increase in bandwidth required and additional power dissipation required for encoding and decoding. In Fig. 3, two rules were carried out. In the first rule, the start byte is set to all zero for frame sync. In the second one, a bit 0 is inserted to the start position of every byte. Alternately, every pixel data has nine bits. Figure 4 shows the prototype device of the imager and wireless subsystem.
2.2. medicine-jet subsystem
The advantage of the ink-jet technology is jet liquid to the target quantita-tively and accurately. There are ink-jet type micro actuator, medicine tank, and control circuit in the subsystem. The micro actuator can jet medicine droplets by the droplet-on-demand. The droplet volume could be a few pico-liters. Due to the characteristic of the ink-jet technology, the medicine
1450 C.-L. CHIU AND C.-T. CHEN
Fig. 4. The prototype device of the imager and wireless subsystem.
could be put in the medicine tank of the capsule, brought and jetted to the nidus. The procedure could eliminate discomfort and side effect. Figure 5 shows the subsystem that includes ink-jet type module and medicine tank. The advantage of the ink-jet type is the accurate droplet volume that ranges from a few pico-liters to several hundred of pico-liters.
2.3. post-processor subsystem
The program of image processing is written using National Instruments LabVIEW and runs in personal computer as a controller. The program automatically captures an image using wireless receiving module, which decodes the RF data and extracts the interest zone from the image. For example, if the interested color is red, then the program will depict the ROI (region of interest) contours in the image window. The computer
structure of the collagen jetted from cartridge has not been destroyed and the activity still keeps the same as before.
3. Conclusion
Since the wireless capsule endoscope with medicine-jet could significantly eliminate the pain of patients and side effect of medicines, the concept and prototype is successfully developed in the study. The experiments show that the elementary working functions of the prototype system works well. The miniaturization of the full system would be necessary for future work for practical use of human body.
References
Ahmadian, M., B.W. Flynn, A.F. Murray and D.R.S. Cumming. Proc. 25th Ann. Int. Conf. IEEE 3028, 2003.
ElecVision. Data Sheet of EVS100k—ARAMIS EVS100k COLOR IMAGE SENSOR. ElecVision Inc, 2003.
RFWaves. RFW112 ISM Transceiver Chipset Preliminary Datasheet. RFWaves Ltd. 2003.
Park, H.J., H.W. Nam, B.S. Song, J.L. Choi, H.C. Choi, J.C. Park, M.N. Kim, J.T. Lee and J.H. Cho.
Microtechnologies in Medicine & Biology 2nd Annual International IEEE-EMB Special Topic Confer-ence on, 2–4 May 2002, 273, 2002.
