Medical Capsule Sensor Calibration for Biliverdin Interference
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Solution Overview
Problem
Existing medical sensors struggle to reliably differentiate between blood and bile containing Biliverdin, particularly in patients with liver conditions, leading to false positive readings due to similar optical properties of Biliverdin and blood, which can mimic the presence of blood and delay critical diagnosis.
Innovation Solution
A medical capsule equipped with a sensor device that emits monochromatic light of different wavelengths, including violet, green, and red, and calculates a quotient of red to green light intensity to distinguish between blood and bile containing Biliverdin, using a correction factor or suppression parameter to adjust measurements and prevent false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor uses violet and red light wavelengths to detect blood based on optical absorption properties, then blood detection capability is improved, but false positive readings occur when Biliverdin is present in bile
Solution Approach 1:
The patent introduces a third wavelength parameter (green light at 530-580nm) to the existing two-wavelength system. By measuring light absorption at three distinct wavelengths and analyzing the spectral pattern, the sensor can differentiate between blood and Biliverdin based on their unique absorption signatures across the spectrum, rather than relying on a single ratio that could be ambiguous
Solution Approach 2:
The green wavelength measurement acts as an intermediary parameter that provides additional information to disambiguate between blood and Biliverdin. The green absorption measurement serves as a mediator that, when combined with violet and red measurements, creates a more reliable diagnostic signature for distinguishing these two substances with similar optical properties
2Adaptability or versatility
If the sensor measures light transmission at multiple wavelengths to differentiate substances, then differentiation capability is improved, but device complexity increases
Solution Approach 1:
The patent divides the detection function into three separate wavelength channels (violet, green, red), each with its own LED and photodetector pair. This segmentation allows independent optimization of each wavelength measurement while maintaining a modular structure that processes each channel separately before combining the results for final analysis
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively differentiates between blood and bile containing Biliverdin, reducing the risk of false positive readings and enhancing the reliability of blood detection, especially in conditions where Biliverdin concentrations are high.
Implementation Method 1
The at least one light emitting element, preferably at least one LED, alternatively emits (preferably monochromatic) violet light of a wavelength of about 380-450nm, green light of a wavelength of about 530-580nm, and red light of a wavelength of about 620-750nm
Implementation Method 2
the at least one light detecting element generates a separate sensor signal associated with measured light intensities Iviolet, Igreen, and Ired of at least each of the wavelength ranges of the light from the light emitting element
Implementation Method 3
Biliverdin exhibits a higher absorption of violet light with a wavelength of around 415nm than Bilirubin (however still less than Haem), resulting in a lower transmission intensity of violet light
Data Source
Figure 1~2
Figure 3~4
AI summary
A medical capsule (1) with a sensor device (6) comprising a light emitting element (8) and a light detecting element (9) with the sensor device (6) being adapted to detect the presence or non-presence of blood and / or Biliverdin based on the light absorption properties of blood and Biliverdin. The medical capsule (1) is provided with a casing (2) forming a gap (5) at its outer surface. The light emitting element (8) alternatively emits violet light of a wavelength of about 380-450nm, green light of a wavelength of about 530-580nm, and red light of a wavelength of about 620-750nm, whereas the light detecting element (9) generates a separate sensor signal associated with measured light intensities Iviolet, Igreen, and Ired of at least each of the wavelength ranges of the light from the light emitting element (8). By evaluating a quotient Ired/Igreen, a false-positive detection of blood can be avoided. The present disclosure also relates to a calibration method for said medical capsule (1).