Photoacoustic Hemoglobin Contrast
Unmix two-wavelength photoacoustic signals into hemoglobin contributions and saturation.
Description
Two-wavelength photoacoustic unmixing solves for two hemoglobin contributions using supplied spectral coefficients.
Two-wavelength photoacoustic unmixing solves for two hemoglobin contributions using supplied spectral coefficients. Saturation is their normalized oxyhemoglobin share.1
Unmix two-wavelength photoacoustic signals into hemoglobin contributions and saturation.
When to use Photoacoustic Hemoglobin Contrast
Use this tool to unmix two-wavelength photoacoustic signals into hemoglobin contributions and saturation.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Photoacoustic Hemoglobin Contrast and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter firstSignal, secondSignal, oxyCoefficientFirst, deoxyCoefficientFirst, oxyCoefficientSecond, deoxyCoefficientSecond using the field table and calculation rules, then run the tool.
- Read oxyhemoglobin, deoxyhemoglobin, oxygenSaturation. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| firstSignal | First-wavelength photoacoustic signal | number | Required |
| secondSignal | Second-wavelength photoacoustic signal | number | Required |
| oxyCoefficientFirst | Oxyhemoglobin coefficient at first wavelength | number | Required |
| deoxyCoefficientFirst | Deoxyhemoglobin coefficient at first wavelength | number | Required |
| oxyCoefficientSecond | Oxyhemoglobin coefficient at second wavelength | number | Required |
| deoxyCoefficientSecond | Deoxyhemoglobin coefficient at second wavelength | number | Required |
Enter finite signed signals and coefficients. Reject exactly zero determinant or solved total; invert the 2×2 system and return both components and saturation.
[oxy,deoxy]=A⁻¹[firstSignal,secondSignal]; saturation=oxy/(oxy+deoxy) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| oxyhemoglobin | Solved oxyhemoglobin contribution | number |
| deoxyhemoglobin | Solved deoxyhemoglobin contribution | number |
| oxygenSaturation | Oxygen saturation fraction | number |
{
"input": {
"firstSignal": 5,
"secondSignal": 4,
"oxyCoefficientFirst": 1,
"deoxyCoefficientFirst": 2,
"oxyCoefficientSecond": 2,
"deoxyCoefficientSecond": 1
},
"output": {
"oxyhemoglobin": 1,
"deoxyhemoglobin": 2,
"oxygenSaturation": 0.3333333333333333
}
}Limitations and assumptions
Negative components and saturation outside 0–1 are accepted. No fluence correction, spectral calibration or clinical oxygenation assessment is supplied.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Isotope Abundance Correction: Invert a two-isotopologue natural-abundance correction matrix. For a complementary task, use SHG Polarization Anisotropy: Calculate parallel/perpendicular SHG ratio and polarization anisotropy.
References
-
Photoacoustic Hemoglobin Contrast — tool.io
Similar or alternative tools
- Isotope Abundance Correction
Invert a two-isotopologue natural-abundance correction matrix.
- SHG Polarization Anisotropy
Calculate parallel/perpendicular SHG ratio and polarization anisotropy.