Towards a single shot holographic diagnosis of Schistosomiasis haematobium
Derk van Grootheest (TU Delft - Applied Sciences)
Gleb Vdovin – Mentor (TU Delft - Mechanical Engineering)
Tope Agbana – Mentor (TU Delft - Mechanical Engineering)
Nandini Bhattacharya – Graduation committee member (TU Delft - ImPhys/Medical Imaging)
Jeroen Kalkman – Graduation committee member (TU Delft - ImPhys/Computational Imaging)
Jan-Carel Diehl – Graduation committee member (TU Delft - Industrial Design Engineering)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Large scale, highly sensitive and specific diagnostic tools are needed to eliminate the transmission of schistosomiasis. This report expands upon the novel approach from M. Hoeboer and P.M. Nijman. Their Smart Optical Diagnostic Of Schistosomiasis device (SODOS), combining the principles of flow cytometry and digital holography, was able to detect schistosomiasis haematobium eggs in a 10 ml urine sample. However the mechanical complexity made it difficult to control the flow and more than 650 frames needed to be processed for each sample. The reason for this was the small flow cell volume examined within each frame. This report shows it is possible to increase the volume while maintaining the required resolution for accurate diagnosis. The size of the volume is limited by the sensor’s pixel pitch, the sensor area, the shutter time of the sensor, the thickness of the volume, the density of particles and to a lesser extent the distance of the volume to the sensor and the wavelength of the source. The density of particles in combination with the thickness of the volume proved to be
the main limiting factors. With to many particles the scattered light causes a cloudy, speckle pattern on the sensor, which does not give the desired resolution upon reconstruction. By using a 24MP APSC CMOS colour sensor, present in the Canon EOS M50 camera, in combination with a larger volume it was possible to reconstruct eggs throughout 1.5 ml of urine using a single frame, decreasing the total required number of frames to 7. The volume thickness was 5 mm. Increasing the thickness to analyse the required 10 ml of urine in a single frame was not feasible due to scattering. However when
immersing the eggs in a Phosphatebuffered saline solution a 14 ml volume, with a thickness of 43 mm, could be analysed successfully, showing the possibilities of implementing the technique in other fields as well. The Fraunhofer particle field holography theory proved to be a valid model when making predictions regarding the resolution throughout the volume as well as providing information on the axial position of the particles.