Non-contact heat transfer models identification for laser hyperthermia of semi-transparent materials

The identification of mathematical models of heat transfer traditionally involves the installation of temperature sensors inside the sample under study and registration of the response to external thermal effects. In cases where the use of contact methods for measuring temperature is impossible, it is necessary to develop new approaches to determining the unknown thermophysical and radiation-optical characteristics. Laser hyperthermia of superficial tissues is one such case. The paper proposes a method for identifying a model of one-dimensional unsteady heating of a semitransparent sample using non-contact thermometry. A feature of the physical process under consideration is the possibility of its discretization. Due to this, a two-stage iterative procedure for solving the inverse heat transfer problem was formulated. The implementation of the proposed algorithm using software made it possible to carry out a computational experiment. The results showed the effectiveness of this approach. The presented method can be used in the development of means for monitoring and regulating the laser hyperthermia procedure.

The impact of laser-induced thermocoagulation effects on the optical spectra of brain tissues

In this work, the results of spectral and optical studies of the grey matter tissues of the brain by a laser hyperthermia action are presented. The coefficients of optical absorption and transport scattering in the spectral range of 250-1500 nm are determined, and the features of the spatial distribution of the laser radiation intensity in the studied objects are identified. It is shown that the coagulation effects lead to compaction and an increase in the concentration of endogenous chromophores and structural elements, which is reflected in the optical properties of biological objects.

Treatment of small and medium retinoblastoma tumors with Iris diode laser

Purpose: Differing techniques have been reported for focal laser therapy for patients with small and medium retinoblastoma. We report the technique used at our center; and report the functional and anatomical outcomes for small and medium retinoblastomas treated with focal laser therapy with or without systemic chemotherapy. Methods: A retrospective case study was conducted including pediatric patients with macular retinoblastoma treated with systemic chemotherapy and laser ablation from July 1990 to July 2015 at Washington University School of Medicine/Saint Louis Children’s Hospital. Results: Fourteen eyes (11 patients) with small and medium retinoblastoma tumors were treated with repetitive indirect laser hyperthermia and seven of those patients were treated with systemic chemotherapy as well. Using the International Retinoblastoma classification, one eye was stage A, 10 eyes were stage B, and three eyes were stage C. The mean follow-up time was 7.7 years. There were no recurrences of tumor in the patients. Final visual acuity outcomes were 20/20 to 20/50 in four eyes, 20/60 to 20/200 in four eyes, and 20/400 or less in six eyes. None of the patients developed metastatic disease. Conclusions: The evidence for systemic chemotherapy and diode laser therapy is limited to case series and retrospective reviews, but evidence suggests that it is an effective treatment for small and medium sized retinoblastoma tumors involving the macula with the potential for good visual outcomes.

Numerical Analysis of Breast Cancer Cell with Gold Nanoparticles Necrosis by Laser Hyperthermia

Laser hyperthermia treatment of cancer tissue is widely used in cancer treatment to destroy cancer cells. This study focus on the mechanisms of heat transfer in biological tissues to minimize damage to the tissues resulting from extra heat applied. The important feature of this method is heating of specific region to raise its temperature to a threshold temperature and destroying cancer cells without to destroy surrounding tissue. In this study, we have used the combinations of laser light and gold nanoparticles to investigate the influence of nanoparticles on the spatial distribution of temperature in the tumor and healthy tissues. Accurate simulations and solving Penne’s bio-heat transfer equation were used to solve and model the thermal tumor breast cancer in the presence of gold. Nanoparticles of some particular sizes and concentrations were selected. We would like here to stress that our attempt was a theoretical and computer model with some real and hypothesized parameters and homogeneous target. The results of this study help the doctors in the study for results of hyperthermia treatment before using it on the vivo by known the properties of the laser used and the properties of the breast tumor trying to reduce the damage of the treatment.

BIOMECHANICS OF SUPERPARAMAGNETIC NANOPARTICLES FOR LASER HYPERTHERMIA

Nanoparticle hyperthermia treatment is progressing with the passage of time, and with the development in the field of hybrid nanoparticles synthesis. The transient heat transfer in magnetite–graphene nanocomposite in three dimension under conduction is studied during this research. The proposed model is simulated in finite element solver framework. Novel hybrid nanoparticles were synthesized. Their chemical properties and their heat transfer properties were examined. By mathematical modeling results, the effective hybrid nanoparticle is chosen that can be used as a drug in hyperthermia process. Current developments in nanotechnology have improved the ability to precisely modify the features and properties of MNPs for these biomedical applications. The accurate control on the magnetic properties of the particle is the key in hyperthermia applications. By these magnetic particles, wished temperature can be achieved for laser hyperthermia. In this paper, study is done for understanding the properties and novelty of the new nanoparticles. The merits and demerits of synthesized hybrid nanoparticles are also discussed either the composites can used as a drug or not.

Preparation of photothermal-chemotherapy nanohybrids by complexation of gold nanorods with polyamidoamine dendrimers having poly(ethylene glycol) and hydrophobic chains

Functional dendrimer-gold nanorod hybrid for combination of anticancer drugs and laser hyperthermia towards efficient cancer treatment with less-adverse effects.

Controllable Fabrication and Characterization of Gold Nanoparticles: Enhanced Therapeutic Approaches in Cancer

Energy trans-ducting gold nano-particles, with well-being physical, chemical and optical properties for utilization in different types of cancer therapy can be prepared through chemical seed growth reduction method. Gold nano particle is a umbrella term have a variety of size and shape. More regular gold nano-particles can be obtained by reduction of HAuCl4, selection of chemicals and parameters of growth medium are set in accordance with the required category of nano-particles. Nano-particles have longest dimension of 100 nm. Therapeutic treatments like photo-imaging, gene delivery, drug delivery, cell labeling and photo thermal therapy can be done by gold nano particles. They reduce the side effects of conventional therapy due to high target specificity and absorb and scatter specific wavelength of laser. Hyperthermia in cancerous cells is generated without damaging surrounding healthy tissues, cause the cell death by necrosis and apoptosis. The overall morphology of gold nano particles can be characterized by SEM and TEM.