Pulse Oxigraphy: And other new in-depth perspectives through the near infrared window

The aim of this thesis was to investigate the feasability of contactless imaging pulse oximetry (proposed term: pulse oxigraphy). The patent disclosed in chapter 2 claims that such pulse oxigraphy can be achieved with camera-derived photoplethysmographic pulse waves at three wavelengths, preferably being 660, 810 and 940nm. From the absorption curves of hemoglobin and oxyhemoglobin it can be easily derived that two of these wavelengths (660 and 940nm) contain oxygenation-related information, and they have proven to be useful for conventional pulse oximetry (in transmission- mode as well as in reflectance-mode). The additional third wavelength (810nm) lies at a so-called isobestic point where the absorption curves of hemoglobin and oxyhemoglobin intersect. Thus, images and/or plethysmographic pulse waves recorded at 810nm do not contain oxygenation-related information, which is useful for reference purposes when dealing with shadows, reflections, movement artifacts and variations in geometry. With regard to pulse oxigraphy the following results were obtained: In chapter 3 we proved that it is possible to derive photoplethysmographic pulse waves containing the heart rythm of a living person at all three required wavelengths from camera recordings collected at a distance of 72 cm. To investigate and validate the capabilities for pulse oxigraphy with this set up, direct measurements on volunteers were sub optimal, because of: Signal-to-noise issues, sequentially recorded heartbeats for oxygen saturation calculations, and lack of a method to induce prolonged stable and adjustable oxygen saturation levels

Technical Note: Are Currently Used Measurements of Fluorescence Intensity in Near Infrared Fluorescence Imaging During Laparoscopic Cholecystectomy Comparable?

Aims: To investigate whether different calculation methods to express fluorescence intensity (FI) as target-to-background (BG) ratio are comparable and which method(s) match with human perception. Materials and Methods: Comparison of three calculation methods from current literature (OsiriX (R), ImageJ (R), and Photoshop (R)) to objectify FI during laparoscopic cholecystectomy measured at the exact same locations within recorded images of two categories: ex vivo and in vivo. Currently applied formulas to present FI in relation to the BG signal are compared with the subjective assessment by the human observers. These three formulas are Signal contrast = (FI in fluorescence regions-FI in BG)/255; Target-to-background ratio = (FI of target-FI of BG)/FI of BG; Signal-to-background ratio = FI of cystic duct/FI of liver and Target-to-background ratio = (FI of target-noise)/(FI of BG-noise). Results: In our evaluation OsiriX and ImageJ provided similar results, whereas OsiriX values were structurally slightly lower compared with ImageJ. Values obtained through Photoshop were less evidently related to those obtained with OsiriX and ImageJ. The formula Target-to-background ratio = (FI of target-noise)/(FI of BG-noise) was less corresponding with human perception compared with the other used formulas. Conclusions: FI results based on measurements using the programs OsiriX and ImageJ are similar, allowing for comparison of results between these programs. Results using Photoshop differ significantly, making direct comparison impossible. This is an important finding when interpreting study results. We propose to report both target and BG FI in articles, so that proper interpretation between articles can be made

Pulse Oxigraphy and other new in-depty perspectives through the near infrared window.

PZ, TiZ

Reiniging, sterilisatie en opslag

Arts en patiënt moeten er zeker van kunnen zijn dat endoscopen en andere medische instrumenten schoon en veilig zijn aan het begin van elke operatie. Prionen, virussen, bacteriën maar ook restanten van reinigingsmiddelen en desinfectantia kunnen nare ontstekingen en zelfs levensgevaarlijke infecties opleveren. De vaststelling van contaminatie kan leiden tot het terugroepen van patiënten. Dit is voor hen zeer stressvol en voor het ziekenhuis duur en pijnlijk. Het risico van slechte reiniging en sterilisatie is dus groot

Innovaties in 3D-beeldtechniek : Driedimensionaal meekijken met de chirurg

Met de intrede van minimaal invasieve chirurgie werd 3D-zicht minder vanzelfsprekend. Daar komt steeds meer verandering in. In de console van de Da Vinci-robot beschikt de chirurg inmiddels over 3D-zicht, maar de operatieassistenten moeten het nog met tweedimensionaal beeld doen. TNO werkt samen met urologen aan beeldtechnologie waarmee de operatieassistenten óók 3D-beeld hebben en waarmee het hele operatiegebied in 3D vastgelegd kan worden, bijvoorbeeld voor opleidingsdoeleinde

Bioclimatic in medische omgeving. TNO Onderzoek met innovatievoucher SenterNovem

De viertraps-luchtbehandelingstechniek van Bioclimatic is speciaal ontworpen om de lucht te zuiveren van allerlei zwevende deeltjes en micro-organismen. Met een innovatievoucher van SenterNovem heeft het bedrijf een oriënterend onderzoek laten uitvoeren door TNO naar eventuele medische toepassingen. Hierbij werden onder andere ook ozonconcentratiemetingen verricht in een klimaatkame