Misuse or new use of radiation Essay Example | Topics and Well Written Essays - 500 words

Misuse or new use of radiation - Essay Example Earlier, good results were obtained with radiation therapy using grenz rays or superficial x-rays but since such machines are not commonly available now, this modality of treatment is no longer used. This study describes the use of megavoltage radiation with good results. The study involved treatment of nine patients with chronic vesicular dermatitis on their hands, feet, or both, with megavoltage radiation. All patients were refractory to conventional treatments. Six of the nine patients had both their hands and feet treated, while two patients had their hands treated, and one patient had the feet treated. For treatment of the hands, the patients stood at the side of a linear accelerator couch and placed their prone palms on a one centimeter of bolus on the couch. Another one centimeter of bolus was placed on top of the hands. An isocentric anterior-posterior and posterior-anterior technique with 6 MV photons, with field size ranging from 19 Ãâ€" 23 cm to 38 Ãâ€" 24.5 cm was used. The center of midplane between the two pieces of bolus received the radiation dose, with radiation dose prescription depths ranging from 1.0 to 2.5 cm from the patients skin surface (2.0 to 3.5 cm from the bolus). For treatment of feet, the patients lay supine on a linear accelerator couch and reverse on the table. With the knees bent, the feet were placed in a water bath having a one-centimeter bolus. An isocentric right and left lateral technique with 6 MV photons, with field size ranging from 14 Ãâ€" 28 cm to 24 Ãâ€" 34 cm was used. The radiation dose was prescribed to the isocenter with the radiation dose prescription depths ranging from 10.5 to 12.5 cm. The radiation dose given was 1,200 cGy in 8 fractions for 8 patients and 900 cGy in 6 fractions for one patient. Treatments were given twice per week, either on Monday and Thursday or on Tuesday and Friday. An improvement was seen in all patients during

What is Biology Essay Example | Topics and Well Written Essays - 500 words

What is Biology - Essay Example Later, I learned that although this definition is sound, it is not detailed or acceptable. After joining the biology class, I realized that there have been numerous debates and definitions of the subject biology. Indeed, scientists especially biologists have conducted various studies on the subject with an aim of coming up with a universal, acceptable, detailed, and scientific definition and meaning of biology. As a result, scientific research has derived the acceptable definition of biology. The definition entails all aspects of living things. Scientists derived the word biology from Greek words bios, which means life, and the word logos that means study (Norwegian University of Science and Technology, 2015). As such, research defines biology as the study of the science of life and living organisms that relates to the structure, function, growth, origin, evolution, and distribution of living organisms (Bagley, 2014). Indeed, research establishes various fields of biology that include biochemistry, cellular biology, botany, ecology, genetics, evolutionary biology, molecul ar biology, zoology, and physiology (Bagley, 2014). The history of biology dates back to the ancient times when human beings had to study the animals they hunted and plants they gathered (Bagley, 2014). Aristotle is the first person to practice zoology where he performed detailed investigations of marine life and plants (Bagley, 2014). Theophrastus derived the first botanical terms in 300 B.C with respect to the nature and life cycle of plants. Moreover, German botanist Leonhard Fuchs wrote the first biology book in 1542 while Carolus Linnaeus inaugurated the initial Binomial classification in 1735 (Bagley, 2014). The discovery of microscopes allowed Robert Hooke to examine plant tissue in 1665 and derived the term cells. In the 19th century, botanists and entomologists discovered and described various species (Bagley, 2014). Indeed, Charles