History of the X-Ray

History of the X-Ray All light and radio waves belong to the electromagnetic spectrum and are all considered different types of electromagnetic waves, including: microwaves and infrared bands whose waves are longer than those of visible light (between radio and the visible)and UV, EUV, X-rays, and g-rays (gamma rays) with shorter wavelengths. The electromagnetic nature of x-rays became evident when it was found that crystals bent their path in the same way as gratings bent visible light: the orderly rows of atoms in the crystal acted like the grooves of a grating. Medical X-rays X-rays are capable of penetrating some thickness of matter. Medical x-rays are produced by letting a stream of fast electrons come to a sudden stop at a metal plate; it is believed that X-rays emitted by the Sun or stars also come from fast electrons. The images produced by X-rays are due to the different absorption rates of different tissues. Calcium in bones absorbs X-rays the most, so bones look white on a film recording of the X-ray image, called a radiograph. Fat and other soft tissues absorb less and look gray. Air absorbs the least, so lungs look black on a radiograph. Wilhelm Conrad Rà ¶ntgen - First X-ray On 8 Nov 1895, Wilhelm Conrad Rà ¶ntgen (accidentally) discovered an image cast from his cathode ray generator, projected far beyond the possible range of the cathode rays (now known as an electron beam). Further investigation showed that the rays were generated at the point of contact of the cathode ray beam on the interior of the vacuum tube, that they were not deflected by magnetic fields, and they penetrated many kinds of matter. A week after his discovery, Rontgen took an X-ray photograph of his wifes hand which clearly revealed her wedding ring and her bones. The photograph electrified the general public and aroused great scientific interest in the new form of radiation. Rà ¶ntgen named the new form of radiation X-radiation (X standing for Unknown). Hence the term X-rays (also referred as Rà ¶ntgen rays, though this term is unusual outside of Germany). William Coolidge X-Ray Tube William Coolidge invented the X-ray tube popularly called the Coolidge tube. His invention revolutionized the generation of X-rays and is the model upon which all X-ray tubes for medical applications are based. Other inventions of Coolidge: invention of ductile tungsten A breakthrough in tungsten applications was made by W. D. Coolidge in 1903. Coolidge succeeded in preparing a ductile tungsten wire by doping tungsten oxide before reduction. The resulting metal powder was pressed, sintered and forged to thin rods. A Very thin wire was then drawn from these rods. This was the beginning of tungsten powder metallurgy, which was instrumental in the rapid development of the lamp industry - International Tungsten Industry Association (ITIA) A computed tomography scan or CAT-scan uses  X-rays  to create images of the body.  However, a radiograph (x-ray) and a  CAT-scan  show different types of information. An x-ray is a two-dimensional picture and a CAT-scan is three-dimensional. By imaging and looking at several three-dimensional slices of a body (like slices of bread) a doctor could not only tell if a tumor is  present but roughly how deep it is in the body. These slices are no less than 3-5 mm apart. The newer spiral (also called helical) CAT-scan takes continuous pictures of the body in a spiral  motion so that there are no gaps in the pictures collected. A CAT-scan can be three dimensional because the information about how much of the X-rays are passing through a body is collected not just on a flat piece of film, but on a computer. The data from a CAT-scan can then be computer-enhanced to be more sensitive than a plain radiograph. Inventor of the Cat-scan Robert Ledley was the inventor of CAT-Scans a diagnostic x-Ray system. Robert Ledley was granted patent #3,922,552 on November 25th in 1975 for a diagnostic X-ray systems also known as CAT-Scans.

Learn 7 Facts About the Sistine Chapel

Learn 7 Facts About the Sistine Chapel Michelangelos Sistine Chapel ceiling is one of the most influential artworks of all time and a foundational work of Renaissance Art. Painted directly on the ceiling of the Sistine Chapel in the Vatican, the masterpiece depicts key scenes from the Book of Genesis. The complex narratives and skillfully painted human figures stunned viewers when the painting was first unveiled to the public in 1512 and continues to impress the thousands of pilgrims and tourists from around the world who visit the chapel every day. Below are seven essential facts about the Sistine Chapel ceiling and its creation. The Paintings Were Commissioned by Pope Julius II   In 1508, Pope Julius II (also known as Giulio II and Il papa terribile), asked  Michelangelo to paint the Sistine Chapels ceiling. Julius was determined that Rome should be rebuilt to its former glory, and had embarked on a vigorous campaign to achieve the ambitious task. He felt that such artistic splendor would not only add luster to his own name, but also serve to supersede anything that Pope Alexander VI (a Borgia, and Julius rival) had accomplished. Michelangelo Painted Over 5,000 Square Feet of Frescoes   The ceiling measures about 40 meters (131 feet) long by 13 meters (43 feet) wide. Although these numbers are rounded, they demonstrate the enormous scale of this nontraditional canvas. In fact, Michelangelo painted well over 5,000 square feet of frescoes. The Panels Depict More Than Just Scenes From the Book of Genesis The ceilings well-known central panels depict scenes from the Book of Genesis, from the Creation  to the Fall to shortly after Noahs deluge. Adjacent to each of these scenes on either side, however, are immense portraits of prophets and sibyls who foretold the coming of the Messiah. Along the bottoms of these run spandrels and lunettes containing the ancestors of Jesus and stories of tragedy in ancient Israel. Scattered throughout are smaller figures, cherubs, and ignudi (nudes). All told, there are more than 300 painted figures on the ceiling. Michelangelo Was a Sculptor, Not a Painter Michelangelo thought of himself as a sculptor and preferred working with marble to almost any other material. Prior to the ceiling frescoes, the only painting hed done was during his brief stint as a student in Ghirlandaios workshop. Julius, however, was adamant that Michelangelo - and no other- should paint the Chapels ceiling. To convince him, Julius offered as a reward to Michelangelo the wildly lucrative commission of sculpting 40 massive figures for his tomb, a project that appealed much more to Michelangelo given his artistic style. The Paintings Took Four Years to Finish It took Michelangelo a little over four years, from July of 1508 to October of 1512, to finish the paintings. Michelangelo had never painted frescoes before and was learning the craft as he worked. Whats more, he chose to work in  buon fresco, the most difficult method, and one normally reserved for true masters. He also had to learn some wickedly hard techniques in perspective, namely painting figures on curved surfaces that appear correct when viewed from nearly 60 feet below. The work suffered numerous other setbacks, including mold and miserable, damp weather that disallowed plaster curing. The project was further stalled when Julius left to wage war and again when he fell ill. The ceiling project and any hope Michelangelo had of being paid were frequently in jeopardy while Julius was absent or near death. Michelangelo Didnt Really Paint Lying Down   Although the classic film The Agony and the Ecstacy,  depicts Michelangelo (played by Charlton Heston) painting the frescoes on his back, the real Michelangelo didnt work in this position. Instead, he conceived and had constructed a unique scaffolding system sturdy enough to hold workers and materials and high enough that mass could still be celebrated below. The scaffolding curved at its top, mimicking the curvature of the ceilings vault. Michelangelo often had to bend backward and paint over his head - an awkward position that caused permanent damage to his vision. Michelangelo Had Assistants Michelangelo  gets, and deserves, credit for the entire project. The complete design was his. The sketches and cartoons for the frescoes were all of his hand, and he executed the vast bulk of the actual painting by himself. However, the vision of Michelangelo toiling away, a solitary figure in a vacant chapel, isnt entirely accurate. He needed many assistants  if only to mix his paints, scramble up and down ladders, and prepare the days plaster (a nasty business). Occasionally, a talented assistant might be entrusted with a patch of sky, a bit of landscape, or a figure so small and minor it is barely discernible from below. All of these were worked from his cartoons, however, and the temperamental Michelangelo hired and fired these assistants on such a regular basis that none of them could claim credit for any part of the ceiling.