Optical properties of native and coagulated porcine liver tissue between 400 and 2400 nm

Ritz, J.‐P.; Roggan, A.; Isbert, C.; Müller, G.; Buhr, H. J.; Germer, C.-T.

doi:10.1002/lsm.1134

Cited by 218 publications

(159 citation statements)

References 31 publications

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“…Scattering data for muscle tissue was retrieved from Simpson, Kohl et al (1998), using an αλ -β (λ, wavelength) extrapolation for the shorter wavelengths, with a g = 0.90 assumption. The OP:s of liver was compiled from Ritz, Roggan et al (2001) while the OP:s of gray and white matter were retrieved from Yaroslavsky, Schulze et al (2002). We assumed a blood oxygen saturation of 80 % and a blood volume concentration of 1.0 % in muscle (van der Zee 1992), 20 % in liver (Taniguchi, Koyama et al 1995), 4.5 % in gray matter, and 2.5 % in white matter (Hamberg, Hunter et al 1996).…”

Section: Tissue Modelsmentioning

confidence: 99%

Measurement depth and volume in laser Doppler flowmetry

Fredriksson

Larsson

Strömberg

2009

Microvascular Research

138

128

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Abstract:A new method for estimating the measurement depth and volume in laser Doppler flowmetry (LDF) is presented. The method is based on Monte Carlo simulations of light propagation in tissue. The contribution from each individual Doppler shift is calculated and thereby multiple Doppler shifts are handled correctly. Different LDF setups for both probe based (0.0, 0.25, 0.5, and 1.2 mm source-detector separation) and imaging systems (0.5 and 2.0 mm beam diameter) are considered, at the wavelengths 453 nm, 633 nm, and 780 nm. Non-linear speckle pattern effects are accounted for in the imaging system setups. The effects of tissue optical properties, blood concentration, and blood oxygen saturation are evaluated using both homogeneous tissue models and a layered skin model. The results show that the effect on the measurement depth of changing tissue properties is comparable to the effect of changing the system setup, e.g. sourcedetector separation and wavelength. Skin pigmentation was found to have a negligible effect on the measurement depth. Examples of measurement depths are (values are given for a probe based system with 0.25 mm source-detector separation and an imaging system with a 0.5 mm beam diameter, respectively, both operating at 780 nm): muscle -0.55/0.79 mm; liver -0.40/0.53 mm; gray matter -0.48/0.68 mm; white matter -0.20/0.20 mm; index finger pulp -0.41/0.53 mm; forearm skin -0.53/0.56 mm; heat provoked forearm skin -0.66/0.67 mm.

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Section: Tissue Modelsmentioning

confidence: 99%

Measurement depth and volume in laser Doppler flowmetry

Fredriksson

Larsson

Strömberg

2009

Microvascular Research

138

128

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“…Based on values of R and T as well as thickness of the samples, the optical properties of sample were calculated using the inverse adding-doubling (IAD, Scott Prahl, 2007) program. In addition, the penetration depth before and after glycerol treatment were also calculated as following equation [21].…”

Section: Experimental Instrumentsmentioning

confidence: 99%

Enhancement of skin optical clearing efficacy using photo‐irradiation

Liu¹,

Zhi²,

Tuchin³

et al. 2010

Lasers Surg Med

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Background and Objectives: Tissue optical clearing technique based on immersion of tissues into optical clearing agents (OCAs) can reduce the scattering and enhance the penetration of light in tissue. However, the barrier function of epidermis limits the penetration of OCAs, and hence is responsible for the poor optical clearing efficacy of skin by topical action. In this study, a variety of light irradiation was applied to increase permeability of agents in skin and improve the optical clearing efficacy. Study Design/Materials and Methods: Different light sources with different dose, i.e, CO 2 laser, Nd:YAG laser (532 and 1,064 nm) with different pulse modes and Intense Pulsed Light (IPL) (400-700 and 560-950 nm) were used to irradiate rat skin in vivo, and then glycerol was applied onto the irradiated zone. VIS-NIR spectrometer was utilized to monitor the changes of reflectance. In vitro skin samples were also irradiated by Q-switched Nd:YAG laser (1,064 nm) and then treated by glycerol for 10-60 minutes. Based on the measurement of the reflectance and transmittance of the samples, the optical properties of skin and penetration depth of light were calculated. Results: Results show that photo-irradiation with appropriate dose combining with the following glycerol treatment is able to reduce in vivo skin reflectance. Compared with the control group, the maximal changes in reflectance are ninefold at 575 nm and eightfold at 615 nm, respectively, which were caused by Q-switched 1,064-nm Nd:YAG laser irradiation and following glycerol treatment. The results for in vitro skin demonstrate that the joint action can significantly increase the optical penetration depth in samples. Conclusions: The combination of Q-switched Nd:YAG (1,064 nm) laser and glycerol could enhance optical skin clearing efficacy significantly. This study provides a noninvasive way to improve the optical clearing of skin, which will benefit the skin optical therapy.

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“…Tumor imaging was successfully demonstrated in a canine prostate cancer model [24] using this system. In the context of thermal therapy, the tissue optical scattering typically increases by 2-to 5-fold upon coagulation due to changes in tissue cell density and protein denaturation, as shown in several studies [26][27][28][29][30]. Hence, direct monitoring of the photocoagulation front is proposed using TRDOT [31].…”

Section: Introductionmentioning

confidence: 99%

Diffuse optical tomography to monitor the photocoagulation front during interstitial photothermal therapy: Numerical simulations and measurements in tissue-simulating phantoms

Wilson

Piao

et al. 2014

Photonics &Amp; Lasers in Medicine

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Near-infrared interstitial photothermal therapy (PTT) is currently undergoing clinical trials as an alternative to watchful waiting or radical treatments in patients with low/intermediate-risk focal prostate cancer. Currently, magnetic resonance imaging (MRI)-based thermography is used to monitor thermal energy delivery and determine indirectly the completeness of the target tumor destruction while avoiding damage to adjacent normal tissues, particularly the rectal wall. As an alternative, transrectal diffuse optical tomography (TRDOT) is being developed to image directly the photocoagulation boundary based on the changes in tissue optical properties, particularly scattering. An established diffusion-theory finite-element software platform was used to perform forward simulations to determine the sensitivity of changes in the optical signal resulting from a growing coagulated lesion with optical scattering contrast, for varying light source-detector separations in both longitudinal and transverse imaging geometries. The simulations were validated experimentally in tissue-simulating phantoms using an existing continuous-wave TRDOT system, in a configuration that is representative of one potential intended clinical use. This provides critical guidance for the optimum design of the transrectal applicator probe, in terms of achieving maximum sensitivity to the presence of the coagulation boundary and, consequently, the highest accuracy in determining the boundary location relative to the rectal wall.Keywords: focal prostate cancer; interstitial photothermal therapy; diffuse optical tomography Zusammenfassung: Die interstitielle photothermische Therapie im Nahinfrarotbereich wird derzeit in klinischen Studien als Alternative zum ‚Watchful Waiting' (beobachtendes Abwarten) bzw. zur radikalen Behandlung von Patienten mit Prostatakrebs der Niedrig-und Mittelrisikogruppe untersucht. Derzeit wird die MR-Thermografie eingesetzt, um die Deposition der thermischen Energie zu überwachen und indirekt die vollständige Tumorzerstö-rung bei gleichzeitiger Vermeidung einer Schädigung des angrenzenden gesunden Gewebes, insbesondere der Rektumwand, zu überprüfen. Als Alternative wurde das Verfahren der transrektalen diffusen optischen Tomographie (TRDOT) entwickelt, mit dem Ziel, die Grenzen der Photokoagulation direkt anhand der Veränderungen in den optischen Gewebeeigenschaften, insbesondere der Streuung, darzustellen. Eine etablierte Software-Plattform auf Basis der Diffusionstheorie und Finite-Elemente-Methode wurde zur Durchführung von Vorwärtssimulationen verwendet, um die Empfindlichkeit der Änderungen des optischen Signals in einer wachsenden Koagulationszone mit optischem Streukontrast zu bestimmen -sowohl für unterschiedliche Lichtquelle/Detektor-Abstände als auch in Längs-und Querausrichtung. Die Simulationen wurden mit einem vorhandenen kontinuierlich abstrahlenden TRDOT-System experimentell in Gewebephantomen validiert -und zwar in einer Konfiguration, die repräsentativ für eine potentielle klinische Anwendung ...

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Optical properties of native and coagulated porcine liver tissue between 400 and 2400 nm

Cited by 218 publications

References 31 publications

Measurement depth and volume in laser Doppler flowmetry

Measurement depth and volume in laser Doppler flowmetry

Enhancement of skin optical clearing efficacy using photo‐irradiation

Diffuse optical tomography to monitor the photocoagulation front during interstitial photothermal therapy: Numerical simulations and measurements in tissue-simulating phantoms

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