Development of a 3‐dimensional tissue lung phantom of a preterm infant for optical measurements of oxygen—Laser‐detector position considerations

Abstract

There is a need to further improve the clinical care of our most vulnerable patients-preterm infants. Novel diagnostic and treatment tools facilitate such advances. Here, we evaluate a potential percutaneous optical monitoring tool to assess the oxygen and water vapor content in the lungs of preterm babies. The aim is to prepare for further clinical studies by gaining a detailed understanding of how the measured light intensity and gas absorption signal behave for different possible geometries of light delivery and receiver. Such an experimental evaluation is conducted for the first time utilizing a specially developed 3-dimensional-printed optical phantom based on a geometry model obtained from computer tomography images of the thorax (chest) of a 1700-g premature infant. The measurements yield reliable signals for source-detector distances up to about 50 mm, with stronger gas absorption signals at long separations and positions related to the lower part of the lung, consistent with a larger relative volume of this. The limitations of this study include the omission of scattering tissue within the lungs and that similar optical properties are used for the wavelengths employed for the 2 gases, yielding no indication on the optimal wavelength pair to use.

Solid phantom recipe for diffuse optics in biophotonics applications: a step towards anatomically correct 3D tissue phantoms

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Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes

“…The 3D printing of lung and thorax phantoms has been described before. 2,[14][15][16][17] Jung et al created lung subvolumes with a cylindrical shape to fit into a commercial phantom. 2 They used polylactic acid (PLA, density 1.25 g/cm³) to print lung tissue and the volume that is presumably air inside the lung was filled with 0.3 mm strips as a supporting structure.…”

Computer simulation analysis of source‐detector position for percutaneously measured O2‐gas signal in a three‐dimensional preterm infant lung

“…The signal amplitude at different source‐detector distances must be considered. Experimentally we have found that GASMAS measurement have reached the signal‐to‐noise limit at a signal amplitude at a level of about 10 −6 of the injected light power) . The precise threshold in the detected signal amplitude would obviously depend on the performance of the detection system, for example, the utilized components and the resulting optical noise of the actual GASMAS measurements.…”

“…To do this, computed tomography (CT) images of premature infants have been used to construct three‐dimensional (3D) computer models of the thorax of these infants. Such a computer model was employed to create a 3D printed physical phantom, on which possible geometries for GASMAS measurements of lung oxygen concentration were experimentally investigated, as described in a recent paper by our group . In the present work a simulation based light transport model is instead developed.…”