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 ....

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...

Absorption

Haemoglobin Absorbance 540

During absorption, the intensity of an incident electromagnetic wave is attenuated in passing through a medium. The absorbance of a medium is defined as the ratio of absorbed and incident intensities. Absorption is due to a partial conversion of light energy into heat motion or certain vibrations of molecules of the absorbing material. A perfectly transparent medium permits the passage of light without any absorption, i.e. the total radiant energy entering into and emerging from such a medium...