Optical properties of native and coagulated human liver tissue and liver metastases in the near infrared range

Germer, Christoph‐Thomas; Roggan, A.; Ritz, J.‐P.; Isbert, C.; Albrecht, Dirk; Müller, G.; Buhr, H. J.

doi:10.1002/(sici)1096-9101(1998)23:4<194::aid-lsm2>3.0.co;2-6

Cited by 142 publications

(66 citation statements)

References 36 publications

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“…A decrease in the absorption coe±cient ( a ) and anisotropy factor (g) and an increase in the scattering coe±cient ( s ) occurred during the heating procedure, which were due to the protein denaturation. [13][14][15][16] Dynamic changes of°uorescence and re°ectance spectrum have also been reported to correlate with thermal damage in liver tissue and results from radio frequency ablation demonstrated that spectroscopy method is promising for evaluation of thermal ablation e±cacy. [17][18][19] However, such studies on MWA are sparse and no evaluation factors or standards are available.…”

Section: Introductionsupporting

confidence: 84%

Real-Time Assessment of Microwave Ablation Efficacy by Nir Spectroscopic Technique

Zhao

Qian

Liu

et al. 2014

J. Innov. Opt. Health Sci.

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Microwave ablation (MWA) status monitoring in real time plays a key role in assessment of therapeutic e®ectiveness. As a novel real-time assessment method, near infrared spectroscopy (NIRs) was used to evaluate the ablation e±cacy. MWA experiments were carried out on in vitro porcine livers. An optical measurement system for biological tissue is developed by our lab to monitor reduced scattering coe±cient ( 0 s ) at 690 nm of the coagulation zones. It is noted that 0 s of liver tissue, which increases as the liver tissue being ablated, is clearly related with the coagulation status. 0 s of normal tissue and coagulated tissue is 3-5 and 17-19 cm À1 , respectively. Continuous changes of 0 s demonstrate that optical parameter can be used as an e±cacy evaluation factor because it essentially indicates the degree of thermal damage. Compared with temperature, optical parameter is more sensitive and accurate, which is promising for real-time therapeutic e±cacy assessment in MWA.

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Section: Introductionsupporting

confidence: 84%

Real-Time Assessment of Microwave Ablation Efficacy by Nir Spectroscopic Technique

Zhao

Qian

Liu

et al. 2014

J. Innov. Opt. Health Sci.

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“…The works of Ritz et al 21 and others 10,11,[22][23][24][25][26] provide a solid basis for understanding the changes in the optical properties of biological tissues under the effect of heating to increasing temperatures. Formation of metHb following heat exposure has been reported by several authors.…”

Section: Discussionmentioning

confidence: 99%

Monitoring of tumor radio frequency ablation using derivative spectroscopy

et al. 2014

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Abstract. Despite the widespread use of radio frequency (RF) ablation, an effective way to assess thermal tissue damage during and after the procedure is still lacking. We present a method for monitoring RF ablation efficacy based on thermally induced methemoglobin as a marker for full tissue ablation. Diffuse reflectance (DR) spectra were measured from human blood samples during gradual heating of the samples from 37 to 60, 70, and 85°C. Additionally, reflectance spectra were recorded real-time during RF ablation of human liver tissue ex vivo and in vivo. Specific spectral characteristics of methemoglobin were extracted from the spectral slopes using a custom optical ablation ratio. Thermal coagulation of blood caused significant changes in the spectral slopes, which is thought to be caused by the formation of methemoglobin. The time course of these changes was clearly dependent on the heating temperature. RF ablation of liver tissue essentially led to similar spectral alterations. In vivo DR measurements confirmed that the method could be used to assess the degree of thermal damage during RF ablation and long after the tissue cooled.

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“…Temperatures above 100°C will cause vaporization from evaporation of tissue water, and above 300°C, tissue carbonization occurs. Overheating is thus best avoided as carbonization decreases optical penetration and heat conduction and limits the size of lesions produced [33]. …”

Section: General Principles and Techniquesmentioning

confidence: 99%

“…A high optical penetration depth reduces the temperature gradient between the laser fiber and tissue and lessens the risk of overheating which prevents carbonization and vaporization of tissue [33]. The optical penetration depth is greater in metastatic tissue than in normal liver, being 4.2 and 3.0 mm, respectively, at the 1064 wavelength.…”

Section: General Principles and Techniquesmentioning

confidence: 99%

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Laser Ablation for Small Hepatocellular Carcinoma

Pacella

Francica²,

Costanzo

2011

Radiology Research and Practice

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Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and is increasingly detected at small size (<5 cm) owing to surveillance programmes in high-risk patients. For these cases, curative therapies such as resection, liver transplantation, or percutaneous ablation have been proposed. When surgical options are precluded, image-guided tumor ablation is recommended as the most appropriate therapeutic choice in terms of tumor local control, safety, and improvement in survival. Laser ablation (LA) represents one of currently available loco-ablative techniques: light is delivered via flexible quartz fibers of diameter from 300 to 600 μm inserted into tumor lesion through either fine needles (21g Chiba needles) or large-bore catheters. The thermal destruction of tissue is achieved through conversion of absorbed light (usually infrared) into heat. A range of different imaging modalities have been used to guide percutaneous laser ablation, but ultrasound and magnetic resonance imaging are most widely employed, according to local experience and resource availability. Available clinical data suggest that LA is highly effective in terms of tumoricidal capability with an excellent safety profile; the best results in terms of long-term survival are obtained in early HCC so that LA can be proposed not only in unresectable cases but, not differently from radiofrequency ablation, also as the first-line treatment.

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Optical properties of native and coagulated human liver tissue and liver metastases in the near infrared range

Cited by 142 publications

References 36 publications

Real-Time Assessment of Microwave Ablation Efficacy by Nir Spectroscopic Technique

Real-Time Assessment of Microwave Ablation Efficacy by Nir Spectroscopic Technique

Monitoring of tumor radio frequency ablation using derivative spectroscopy

Laser Ablation for Small Hepatocellular Carcinoma

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