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Investigative Duties on Scene
Published in Kevin L. Erskine, Erica J. Armstrong, Water-Related Death Investigation, 2021
Everything on the earth gives off thermal energy, even ice. The hotter something is the more thermal energy it emits. Temperature also affects wavelength and frequency. Objects at room temperature radiate energy as infrared waves. Energy radiating from objects is a range of wavelengths. As an object temperature increases, the wavelength decreases. Hot objects emit shorter wavelengths and higher frequency radiation. Thermal camera specifications list technical details as Noise Equivalent Temperature Differences (NETD), which is a measure for how well a thermal camera can detect thermal differences. NETD are typically expressed in milli-Kelvin or mk. The scientific details of thermal imaging can be very complex, yet the equipment is very easy to use with little training, and the color-coded images are easy to understand and interpret.
Pre-, intra-, and post-treatment use of duplex ultrasound (thermal and non-thermal)
Published in Joseph A. Zygmunt, Venous Ultrasound, 2020
Duplex is also helpful in observation of the vein during therapy. The “action” that occurs near the tip provides evidence that the thermal generator, either RF or laser, is working properly and producing heat. Furthermore, observation of the location of the heating element can be followed. If the patient has an aneurysmal segment, extra thermal energy may be applied to that segment when it is reached. This is also true for large side branches or perforators which can dump blood into the area and cause cooling. If duplex monitoring is not taking place, this could result in suboptimal treatment and potential early failure of one of these areas.
Lasers in Medicine: Healing with Light
Published in Suzanne Amador Kane, Boris A. Gelman, Introduction to Physics in Modern Medicine, 2020
Suzanne Amador Kane, Boris A. Gelman
The light employed in laser surgery does damage because it transfers energy by absorption or scattering to human tissues. Each photon carries energy that can be converted into other forms of energy, such as chemical bond energy. Although energy can be transformed between different types (kinetic energy – energy of motion – chemical bond energy, light energy, etc.), energy cannot be destroyed or created from nothing, a fundamental principle referred to as the conservation of energy. The most common energy transformation in laser surgery involves heating tissue through the absorption of photon energy. Atoms are in constant random motion in gaseous and liquid materials, and they are vibrating around their equilibrium positions in solids. The temperature of the material characterizes the average energy of this motion, and the total energy due to this motion is called the material's thermal energy. The energy carried by light is most often converted into thermal energy of the molecules of the tissue being illuminated; this energy input thus raises the material's temperature. Energy transfers that change the thermal energy of a material are called heat. Thus, the transfer of energy from photons of light can also result in the heating of tissue. For example, heat lamps work by providing infrared radiation that is efficiently absorbed by our tissue as heat. On a clear day this effect is quite evident in the heat we feel from sunlight.
Efficacy of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids: an observational single-center study
Published in International Journal of Hyperthermia, 2021
Milka Marinova, Shiwa Ghaei, Florian Recker, Tolga Tonguc, Olga Kaverina, Oleksandr Savchenko, Dmitrij Kravchenko, Marcus Thudium, Claus C. Pieper, Eva K. Egger, Alexander Mustea, Ulrike Attenberger, Rupert Conrad, Dariusch R. Hadizadeh, Holger Strunk
It can be postulated that the major factor influencing technical success of HIFU is the deposited total energy or energy efficiency factor. As already mentioned, this is dependent on the fibroid composition, blood supply/enhancement type, location, distance from the fibroid ventral side to the skin, and possibly body habitus (abdominal wall thickness, BMI, presence of abdominal wall scars). For example, in patients with a thicker abdominal wall, more energy is absorbed in fatty tissue and consequently less energy can be deposited inside the fibroid [31]. Previous studies showed that US energy is converted into thermal energy, with the highest efficiency at the fat/muscle interface and that fatty tissue easily absorbs thermal energy [32]. However, one pilot study using a portable device (n = 36 patients) found no correlation between the NPVR and the abdominal wall thickness (rectus muscle thickness and subcutaneous fat thickness), original tumor volume or treatment time [33]. Our study was in line with these findings.
Fractional radiofrequency in the treatment of skin aging: an evidence-based treatment protocol
Published in Journal of Cosmetic and Laser Therapy, 2020
Ileana Afroditi Kleidona, Dimitrios Karypidis, Nicholas Lowe, Simon Myers, Ali Ghanem
Radiofrequency (RF) devices use electromagnetic radiation to conduct alternating electric current to biologic tissues, causing motion of charged particles against the tissue’s resistance (impedance). This kinetic energy is converted to thermal energy (12). The heat causes initial collagen contraction and subsequent new collagen synthesis through long-term repair processes, resulting in dermal remodeling and skin tightening. It is hypothesized that since RF is not selectively absorbed by chromophores is safe in darker skin (13). More recently, fractional radiofrequency (FRF) has gained traction as the last generation stratagem combining efficacy and safety in skin rejuvenation. This technique uses minimally invasive microneedles or electrode pins to achieve targeted dermal injury with minimal superficial involvement. The thermal injury results in denaturated fibrils of collagen and initiates a wound healing response (14).
Study of enhanced radiofrequency heating by pre-freezing tissue
Published in International Journal of Hyperthermia, 2018
Kangwei Zhang, Jincheng Zou, Kun He, Lichao Xu, Ping Liu, Wentao Li, Aili Zhang, Lisa X. Xu
In our previous studies, pre-freezing at the temperature of −20 °C for 5 min followed by rapid RF heating at the temperature of 50 °C for 10 min achieved a good prognosis in animal tumor models [12–14]. Considering the patient’s tolerance, a rapid heating can ensure sufficient thermal dose for tumor cell killing within the same operating time. Under the condition of a constant power input, more RF energy could be focused into the targeted region given less heat dissipation in the pre-freezing tissue and a larger ablation volume created within the same duration. This clearly indicates that the combined therapy effectively overcomes the heat sink effect of the blood flow and greatly improves the RFA range. Currently in clinic application, the lethal temperatures for thermal ablation of tumor cells are below –40 °C for cryosurgery and above 60 °C for the RF heating [3]. It is clear that the combined treatment of RF heating with pre-freezing studied here utilizes more a moderate temperature range to ablate tumors more effectively and to protect the surrounding tissue structures, especially in sensitive locations. The clinical application could be achieved through precise control of dynamic thermal energy deposition (dose) via a novel thermal treatment system under development in our laboratory.