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Radiation Safety
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Debbie Peet, Elizabeth Davies, Richard Raynor, Alimul Chowdhury
Some senior Scientists working in either non-ionising or in Radiation Safety become experts in the use and control of lasers in hospitals and gain certification as a Laser Protection Adviser (LPA). Clinical Scientists might provide advice on the choice of room and room layout and minimisation of hazards, as well as carrying out measurements of the laser beam, risk assessments and safety audits. The LPA may hold a senior role within an organisation and sit on safety committees.
Principles of Pathophysiology of Infertility Assessment and Treatment*
Published in Asim Kurjak, Ultrasound and Infertility, 2020
Joseph G. Schenker, Aby Lewin, Menashe Ben-David
Recently, some centers acquired experience with the use of a laser beam for microsurgery. This method offers the operator a well-controlled incision instrument with high maneuverability and precision and a bloodless operating field as the beam seals the blood vessels along its tract. The latter effect, on the other hand, also may be considered a disadvantage because of the thermal damage to the adjacent tissue. For this reason, some operators suggest the use of a laser for salpingostomy, adhesiolysis, and endometriosis, but not for tubal anastomosis.
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
In OCT a laser light is used to produce a stable interference pattern, which can be turned into an image of the near-surface anatomical structure of a tissue. A device used in OCT to produce and record an interference pattern is called an interferometer, schematically shown in Figure 3.37. A laser beam is split into two perpendicular beams by a beam splitter (a glass prism or a partial mirror). One of the beams is then reflected from a mirror, and the other is directed inside a tissue being imaged. A part of the light incident on the tissue is reflected (the other parts are absorbed and refracted). The two beams then recombine inside the beam splitter and produce an interference, which is captured in a light detector. The interference pattern is characteristic of an anatomical structure of the tissue spot irradiated by the laser, in the same way that the interference pattern in thin films depends on their thickness and refractive indices.
Polymer type effect on PLGA-based microparticles preparation by solvent evaporation method with single emulsion system using focussed beam reflectance measurement
Published in Journal of Microencapsulation, 2022
Muhaimin Muhaimin, Anis Yohana Chaerunisaa, Roland Bodmeier
The chord counts of PLGA RG503H microparticles was lower than others. It is due to production of microparticles with the largest size. The square weighted mean chord length of PLGA RG752H were smaller than others, so the chord counts was highest, it is due to PLGA RG752H gave the smallest square weighted mean chord length. This result can be attributed to the particle properties. PLGA RG503H produces slightly opaque microparticles compared to other polymers (Figure 2(a1)). If the laser beam hits a more opaque microparticle, the signal will be scattered to detector. The opaque microparticles were measured with FBRM will give higher scattering value than translucent and transparent one. Due to the absorbance of the opaque microparticles, the backscattered signal is very high intensity, which results in a high degree of chord lenght. This is in agreement with Greaves et al. and was also found by Sparks and Dobbs, who concluded that only droplets or microparticles which are opaque and highly reflective (with microstructure on the surface) give reproducible and accurate results (Sparks and Dobbs 1993, Ruf et al.2000, Wu et al.2011, Greaves et al. 2008, Scheler 2013, Sankaranarayanan et al. 2019).
Efficacy of fractional carbon dioxide laser therapy for burn scars: a meta-analysis
Published in Journal of Dermatological Treatment, 2021
Cong Zhang, Kai Yin, Yu-ming Shen
With the introduction of fractional photothermolysis, laser technology has advanced rapidly to perform fractional resurfacing in traumatic scars and is found to be associated with substantial functional and cosmetic benefits (11–14). Lasers emit a beam of photons from a medium (carbon dioxide (CO2) in case of CO2 laser) which is capable of emitting energy at 10,600 nm. If appropriately used, the CO2 laser offers a very large range of dermatological indications, with great precision for procedures involving incision, excision, vaporization and coagulation. The residual thermal damage caused by the CO2 laser beam helps to ensure a dry field, limits blood loss and swiftly induces the wound healing and tissue remodeling process. Fractionation of the beam of energy into a number of microbeams, the fractional CO2 laser has potential for a range of ablative and non-ablative skin rejuvenation processes (15).
Clinical treatment of intra-epithelia cervical neoplasia with photodynamic therapy
Published in International Journal of Hyperthermia, 2020
Antonio Carlos Figueiredo Vendette, Henrique Luis Piva, Luis Alexandre Muehlmann, Delfrank Ananias de Souza, Antonio Claudio Tedesco, Ricardo Bentes Azevedo
Lesions classified as CIN1 have a low aggression condition and can either regress spontaneously over time or progress slowly toward CIN2 and CIN3. In clinical practice, patients with CIN1 only receive therapeutic intervention if there is a progression. CIN2 and CIN3 lesions present a risk of progressing more rapidly toward invasive lesions, but in the absence of local extension and lymphatic dissemination, they are treated using local therapeutic approaches such as High-Frequency Surgery (CAF), laser ablation, cryotherapy, or hysterectomy. Hysterectomy is considered a radical treatment for early cervical cancer, whereas the cervix and uterus are usually removed (simple hysterectomy). Laser ablation is a technique that uses a laser beam applied to the area to be treated to destroys the altered cells. Cryotherapy is a procedure that uses a cold chemical (liquid nitrogen) to destroy the wanted cells. High-Frequency Surgery uses electric energy (in high voltage) that is transformed into heat and can cut the desired tissue, avoiding at the same time bleeding. All these modalities have similar curative efficacy and must be chosen depending on the risk to the woman [13]. It is worth noting that the structural damage of the cervix, caused by abrasive or invasive techniques, can compromise patients’ reproductive capacity. In this sense, Photodynamic Therapy (PDT), in cervical neoplasia, is known to preserve cervical competence, favoring the uterus' physiological preservation [14].