| 1. |
- Chen, Delong, et al.
(author)
-
Laser-based gas absorption spectroscopy in decaying hip bone : water vapor as a predictor of osteonecrosis
- 2019
-
In: Journal of Biomedical Optics. - 1083-3668. ; 24:6, s. 1-6
-
Journal article (peer-reviewed)abstract
- Affluent blood flow through a complicated net of vessels supplies skeletal bone tissue with oxygen and nutrients. Due to accidental events or physiological processes, the blood supply might be deficient or even disrupted, and the healthy bone decays in a process that, for the hip location, is denoted as osteonecrosis of the femoral head (ONFH) or avascular femoral head necrosis. Early diagnosis is important for the prognosis. X-ray-based imaging, such as CT or MRI, is not of much value for the early detection. As the decay theoretically is associated with the development of gas-filled pores, gas analysis should have diagnostic value. We have introduced gas in scattering media absorption spectroscopy, as a complementary modality. Eighteen extracted femoral joint heads, diseased as well as normal, were investigated. Diseased samples are associated with clear signals due to water vapor, whereas the normal ones largely lack such features. The results suggest that free water vapor could serve as an early indicator of pore development and thus as a promising predictor of ONFH pathological changes, once the technique has been fully refined.
|
|
| 2. |
- Chen, Peng, et al.
(author)
-
Assessment of Free Gas in the Tibial Condyle Bone of the Human Knee by Diode Laser Spectroscopy with Possible Application to Arthrosis Diagnostics
- 2019
-
In: IEEE Journal of Selected Topics in Quantum Electronics. - 0792-1233. ; 25:1
-
Journal article (peer-reviewed)abstract
- The gas in scattering media absorption spectroscopy (GASMAS) technique was used to investigate the possible presence of free gas pores in human condyle bones, extracted from the tibia in knee revision surgical procedures in response to arthrosis development. Following earlier studies showing free gas presence in femoral head bones, decaying because of inadequate blood flow, we investigated condyle bone, where the arthrosis degeneration process, affecting the cartilage cup, is of different origin. Only a minor gas presence was observed in affected condyle samples, in accordance with our finding for non-arthrosis samples. Further, studies of fresh or initially frozen samples showed very similar signals, suggesting that the handling procedure has only a minor importance in these studies. In contrast to the situation for femoral heads, the monitoring of a gas presence would add only little in assessing the arthrosis status in the view of elective surgical procedures.
|
|
| 3. |
- Hu, Lingna, et al.
(author)
-
Optical detection of otitis media using modified spectroscopic otoscope
- 2018
-
In: 2018 Asia Communications and Photonics Conference, ACP 2018. - 9781538661581 ; 2018-October
-
Conference paper (peer-reviewed)abstract
- Otitis media is a common infectious disease in early childhood. We use an optical diagnostic system combining otoscopy and spectroscopy to improve the accuracy of diagnosis of otitis media.
|
|
| 4. |
- Hu, Lingna, et al.
(author)
-
Towards an optical diagnostic system for otitis media using a combination of otoscopy and spectroscopy
- 2019
-
In: Journal of Biophotonics. - : Wiley. - 1864-063X .- 1864-0648. ; 12:6
-
Journal article (peer-reviewed)abstract
- An improved method, where conventional otoscope investigation of human suspicious otitis media is combined with diffuse reflectance spectroscopy and gas in scattering media absorption spectroscopy (GASMAS) is being developed. Otitis media is one of the most common infectious diseases in children, whose Eustachian tube connecting the middle ear with the nasal cavity is more horizontal than for adults, which leads to impaired fluid drainage. At present, the use of an otoscope to visually observe possible changes in the tympanic membrane appearance is the main diagnostics method for otitis media. Inaccurate diagnosis related to similar symptoms, and the difficulty for small children to describe the condition experienced, frequently leads to over-prescription of antibiotics and alarming increase in bacterial resistance development. More accurate diagnostic methods are highly desirable. Diffuse reflectance spectroscopy is a non-invasive quantitative spectroscopic technique that enables to objectively quantify changes in the hemoglobin content of the tympanic membrane related to inflammation. If an infection is present, the ventilatory function of the Eustachian tube is frequently impaired and the middle-ear cavity will be filled with fluid. GASMAS, a non-invasive detection method, can non-invasively determine if gas is replaced by fluid in the middle-ear cavity.
|
|
| 5. |
- Huang, Jing, et al.
(author)
-
Assessment of human sinus cavity air volume using tunable diode laser spectroscopy, with application to sinusitis diagnostics.
- 2015
-
In: Journal of Biophotonics. - : Wiley. - 1864-063X. ; 8:11-12, s. 985-992
-
Journal article (peer-reviewed)abstract
- Sinusitis is a very common disease and improved diagnostic tools are desirable also in view of reducing over-prescription of antibiotics. A non-intrusive optical technique called GASMAS (GAs in Scattering Media Absorption Spectroscopy), which has a true potential of being developed into an important complement to other means of detection, was utilized in this work. Water vapor in the frontal sinuses, related to the free gas volume, was studied at around 937 nm in healthy volunteers. The results show a good stability of the GASMAS signals over extended times for the frontal sinuses for all volunteers, showing promising applicability to detect anomalies due to sinusitis. Measurements were also performed following the application of a decongestion spray. No noticeable signal change was observed, which is consistent with the fact that the water vapor concentration is given by the temperature only, and is not influenced by changes in cavity ventilation. Evaluated GASMAS data recorded on 6 consecutive days show signal stability for the left and right frontal sinus in one of the test volonteers.
|
|
| 6. |
- Huang, Jing, et al.
(author)
-
Gas exchange in fruits related to skin condition and fruit ripening studied with diode laser spectroscopy
- 2016
-
In: Journal of Biomedical Optics. - 1083-3668. ; 21:12
-
Journal article (peer-reviewed)abstract
- The concentration of the biologically active molecular oxygen gas is of crucial importance for fruits in the metabolic respiration, maturation, and ripening processes. In our study, oxygen content and oxygen transport in fruits, exemplified by apples and guavas, were studied noninvasively by gas in scattering media absorption spectroscopy. The technique is based on the fact that free gases typically have 10,000 times narrower absorption features than the bulk material. The technique was demonstrated in studies of the influence of the fruit skin in regulating the internal oxygen balance, by observing the signal response of the internal oxygen gas to a transient change in the ambient gas concentration on peeled and unpeeled fruits. In addition, the gas exchange rate at different ripening stages was also studied in intact guavas.
|
|
| 7. |
- Li, Tianqi, et al.
(author)
-
Application of Tunable Diode Laser Spectroscopy for the Assessment of Food Quality
- 2017
-
In: Applied Spectroscopy. - : SAGE Publications. - 0003-7028 .- 1943-3530. ; 71:5, s. 929-938
-
Journal article (peer-reviewed)abstract
- Adequate food packaging is important to ensure food quality and prolong the shelf life of food. Frequently, the method of modified atmosphere packaging (MAP) is used. We used a tunable diode laser spectroscopy technique to detect the oxygen content in food packages, e.g., in packaged milk and bread. Different detection geometries were adopted to be able to collect scattering light that had passed through the gas volume in the packages, and to avoid the disturbance of ambient air. Furthermore, studies of the bread-baking process have been performed by measuring the water vapor signals in a fermenting dough. The results demonstrate that the technique has a great potential for nonintrusive assessment of food quality and the bread-baking process.
|
|
| 8. |
- Li, Wansha, et al.
(author)
-
Detection of free oxygen and water vapor in fertilized and unfertilized eggs by diode laser spectroscopy-Exploration of diagnostics possibilities
- 2018
-
In: Journal of Biophotonics. - : Wiley. - 1864-063X. ; 11:3
-
Journal article (peer-reviewed)abstract
- Nonintrusive methods for characterizing food products are of increasing interest related to the greater awareness of food safety issues. Hen eggs are an important part in food consumption in most parts of the world. We have investigated an optical method utilizing tunable diode lasers for monitoring free gas in eggs. We show that oxygen signals, recorded around 760nm, increase steadily as eggs become older. Further, we investigated fertilized eggs, which show a quite different temporal behavior during the hatching time. The oxygen signal decreases here with time, while water vapor, recorded around 937nm, shows a steady increase. Conclusions regarding the size of the air cell and the oxygen availability in fertilized eggs are drawn. The technique might be developed for automatic control of egg freshness, as well as for assessing if eggs are fertilized or not.
|
|
| 9. |
- Lin, Huiying, et al.
(author)
-
Diagnostics of femoral head status in humans using high-resolution laser spectroscopy : In vitro studies
- 2017
-
In: CLEO: Applications and Technology, CLEO_AT 2017. - 9781943580279 ; Part F43-CLEO_AT 2017
-
Conference paper (peer-reviewed)abstract
- Osteonecrosis of the femoral head is caused by inadequate blood supply to the affected bone. The bone decay process due to lacking blood supply would be likely to be accompanied by the formation of gas-filled pores. We have introduced diode laser absorption spectroscopy to successfully detect water vapor signals from pores in the femoral heads retrieved from hip replacement operations in 19 patients. The Gas in Scattering Media Absorption Spectroscopy (GASMAS) variety of tunable laser spectroscopy was employed. The results open up for the possibility of improved diagnostics for a very common disease.
|
|
| 10. |
|
|
