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IIB 2000

The Technics of the Whole-Body-Photon-Counting Systems

Martin Markert

International Institute of Biophysics

Ehemalige Raketenstation

Kapellener Straße

D-41472 Neuss, Germany

Abstract

At present, only the entire biophoton emission of a sample, or the local emission of selected points on a sample surface, e.g. human skin, can be measured. However, by use of a photon-detector with a computer-controlled scan-movement, the two-dimensional distribution of the biophoton emission from samples or human bodies can be obtained. In this paper, examples of scan-measurement of leaves and measurement of different points on human skin are presented.

Introduction

Light emission from biological systems is a phenomenon that has been confirmed by numerous experiments with plants, animals and human beings. Due to their low intensity, biophotons have to be measured in a totally lightproof room. Because of this stringent requirement, biophotonic measurements are normally limited to small objects like seeds, parts of plants, animal tissues, etc. However, in order to achieve a better understanding of biological systems it is desirable to detect the biophotonic emission of an entire organism. This paper will describe an attempt in this direction.

Existing measuring systems are either transportable detectors limited to samples of the size of an apple or detectors in darkrooms to measure local areas of human skin. Our aim is to scan the whole surface of an object, e.g. a human body, with a photomultiplier. In this way a two-dimensional image of the local spontaneous photon emission or the local delayed luminescence after light excitation with an optical fiber can be made. The pixel-size can be freely selected between 10^-5 and 10^-2m².

The scanning time is dependent on several factors: the time for the localization of the photon-detector, measuring time, excitation time in the situation of delayed luminescence and the number of scanning points. High resolution requires a large number of scanning points. On the other hand, long measuring times are necessary because of the low intensity of biophoton emission; since human skin emits low intensity of biophotons, long measuring times are needed. In practice this is difficult because one person cannot maintain the same posture over a period of several hours. Therefore, a compromise must be found between the measuring time and the scan resolution. The largest scanning area is 2m x 1m. The measuring time can be adjusted between 10^-3 and 10² s. The time for positioning the detector is approximately 1 s.

Method

In this system, there are two possible measurement methods: spontaneous emission and delayed luminescence.

Spontaneous emission has a low intensity ranging from several counts per second to several hundred counts per second and requires long measuring times in order to get images with an acceptable resolution.

Delayed luminescence is the phenomenon of photon emission after a short excitation with an external light source, e.g. white light, monochromatic light from a thermal light source (Xenon- and halogen-lamp) or laser. The excitation time is adjustable from 10^-1 to 10² s by using the thermal light source with shutter. By using the short pulse-laser the excitation time is only 10^-9 s. Furthermore, it is not necessary to use the shutter during excitation and, therefore, it is possible to observe the complete bioluminescence peak. The maximal intensity of delayed luminescence is in a range of 10² to 10⁴ counts per second.

Experimental Setup

The photon-detector is a photomultiplier from Thorn-Emi (type 9558QA), which is cooled down to –30 °C with a Peltier-element. Signals from the photomultiplier are amplified in a fast preamplifier and filtrated in a discriminator. A counter-card in a PC registers the signal pulses. The integration time of the counter is the measuring time for each pixel. The distance between the photomultiplier and the sample can be determined using an ultrasonic sensor. The thermal light source is a Xenon-lamp with a spectrum of 250 nm to 900 nm. The laser has a wavelength of 337 nm. The photon-detector is moved along three dimensions by means of a stepper-motor.

Result

Measurement methods are selected according to the biophoton emission intensity characteristic of different cell types.

Plant cells have strong spontaneous emission and can, therefore, be scanned at high resolution within a short amount of time. In this case, a high contrast image is observed despite short measuring times.

Since the spontaneous emission intensity of human skin is low and ranges from only 5 to 30 counts per second, this method is not suitable for biophoton emission. Another reason is that there is little difference between local skin areas. Therefore, delayed luminescence is a better choice for biophoton measurements of human skin.

These two methods can be combined and the resulting biophoton emission measurements can be statistically evaluated to yield useful information. For example, by Fourier analysis and cross correlation, information concerning biorhythms can be extracted that indicate levels of the health state of biological organisms. Spontaneous bioemission and delayed luminescence measurements may or may not be correlated for emissions from different parts like, for example, measurements indicate a strong correlation for biophoton emission and delayed luminescence between the left and right hand of a human being. However, biophoton emission measurements and delayed luminescence are not distinctly correlated. Also biophoton emission measurements between different parts, for example, between the forehead and hands are also not correlated. This indicates the complexity of this measuring technique. Further research is clearly needed to further explore these phenomena. One thing is clear in that using this method, useful information can be obtained within a short period of time which can be used to identify not only the state of health of the human being, but could in the near future be developed into a sensor that indicates the effectiveness of a certain therapy.

4. Outlook

Two-dimensional biophoton mapping can be applied in non-invasive medical diagnostics. The symmetry of biophoton emission between left and right body parts may indicate the health state of human beings. For example, one could observe whether the symmetric grade of human body biophoton emission increases or decreases during a certain therapy. This information could then be used to evaluate different therapies. Clearly, further research is needed.

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