Fundamentals and Applications Third[ Enlarged Edition

Biological and medical physics, biomedical engineering biological and medical physics, biomedical engineering The fields of biological and medical physics and biomedical engineering are broad, multidisciplinary and dynamic. They lie at the crossroads of frontier research in physics, biology, chemistry, and medicine. The Biological and Medical Physics, Biomedical Engineering Series is intended to be comprehensive, covering a broad range of topics important to the study of the physical, chemical...

Lasers in Ophthalmology

Lasers Ophthalmology

In ophthalmology, various types of lasers are being applied today for either diagnostic or therapeutic purposes. In diagnostics, lasers are advantageous if conventional incoherent light sources fail. One major diagnostic tool is confocal laser microscopy which allows the detection of early stages of retinal alterations. By this means, retinal detachment and also glaucoma1 can be recognized in time to increase the probability of successful treatment. In this book, however, our interest focuses...

Lasers in Dermatology

Image Skin Cross Section Colour

In dermatology, thermal effects of laser radiation are commonly used, especially coagulation and vaporization. Since the optical parameters of skin, i.e. absorption and scattering, are strongly wavelength-dependent, various kinds of tissue reaction can be evoked by different laser systems. In clinical practice, mainly five types of lasers are currently being used argon ion lasers, dye lasers, CO2 lasers, Nd YAG lasers, and ruby lasers. A schematic cross-section of the human skin is given in...

Energy density jcm2

Co2 Laser Gain Curve

Fig. 4.64. a Ablation curves of fresh and dried bone obtained with a CO2 laser pulse duration 250 s, wavelength 10.6 m . Due to its higher water content, fresh bone is ablated more efficiently. Data according to Forrer et al. 1993 . b Ablation curve of bone obtained with an Er YAG laser pulse duration 180 s, wavelength 2.94 m . Data according to Scholz and Grothves-Spork 1992 Fig. 4.64. a Ablation curves of fresh and dried bone obtained with a CO2 laser pulse duration 250 s, wavelength 10.6 m ....

Analysis of Plasma Parameters

The interaction type of plasma-induced ablation can be used for diagnostic purposes, as well. By means of a spectroscopic analysis of the induced plasma spark, the free electron density and the temperature of the plasma can be evaluated. Moreover, detailed information on the chemical consistency of the target can be obtained, thereby allowing certain conclusions to be drawn regarding the state of health of the investigated tissue volume. One example for the analysis of laser-induced plasmas is...

Cell layer

Chorioidea Tumor

Nerve fiber layer Internal limiting membrane Vitreous body Fig. 4.2. Cross-section of a human retina Fig. 4.2. Cross-section of a human retina The pigment epithelium is strongly attached to the chorioidea. The receptor layer consists of two types of cells - rods and cones. Rods are used in dim light and are primarily located around the macula. Cones are recepting colors in good light and are found especially in the fovea. Obviously, light has to pass through virtually the whole retina beyond...

Bone

Cross-section of a human tooth The enamel is the hardest substance of the human body. It is made of approximately 95 by weight hydroxyapatite, 4 water, and 1 organic matter. Hydroxyapatite is a mineralized compound with the chemical formula Ca10 PO4 6 OH 2. Its substructure consists of tiny crystallites which form so-called enamel prisms with diameters ranging from 4 im to 6 im. The crystal lattice itself is intruded by several impurities, especially Cl-, F-, Na , K , and Mg2 . The...