this contains the occlusal radiography methods for both maxillary and mandibular different occusal radiographic techniques, principles, classification, indications
this contains the occlusal radiography methods for both maxillary and mandibular different occusal radiographic techniques, principles, classification, indications
brief description about CONTENTS Introduction Principles of panoramic imaging Image layer Panoramic machines Panoramic film Patient positioning Interpreting the panoramic imaging INDICATION Advantages Disadvantages Conclusion References
3. INTRODUCTION • Panoramic imaging also called pantomography is a technique for producing a single tomographic image of facial structures that includes both the maxillary and mandibular dental arches and their supporting structures . • This is a curvilinear variant of conventional tomography.
4. PRINCIPLES OF PANORAMIC IMAGE FORMATION • Patero and Numata - describe the principles of panoramic radiography • based on the principle of reciprocal movement of x-ray source and an image receptor around a central point or plane called the image layer, in which the OBJECT of image is located. • OBJECT in front or behind this image are not clearly captured because of their movement relative to the centre of rotation of the receptor and the x-ray source.
5. The film and x-ray tubehead move around the patient in opposite directions in panoramic radiography
6. ROTATION CENTER The pivotal point or axis around which the cassette carrier and tube head rotate is termed rotation center Three basic rotation center used in panoramic radiography Double centre rotation Triple centre rotation moving centre rotation The location and number of rotational centers INFLUENCE size and shape of focal trough
7. IMAGE LAYER • Also known as focal trough • It is a three dimensional curved zone where the structures lying within this layer are reasonably well defined on final panoramic image. • The structures seen on a panoramic image are primarily those located within image layer. • OBJECTSoutside the image layer are blurred magnified are reduced in size. Even distorted to the extent of not being recognizable. • This shape of image layer varies with the brand of equipment used.
8. FOCAL TROUGH
9. FACTORS AFFECTING SIZE OF IMAGE LAYER: Arc path Velocity of receptor and X-ray tube head Alignment of x-ray beam Collimator width The location of image layer change with extensive machine used so recalibration may be necessary if consistently suboptimal images are produced. As a position of object is moved within the image layer size and shape of image layer change.
10. PANORAMIC UNIT
11. A, Orthophos XG Plus extraoral x-ray machine. B, Orthoralix 8500 extraoral x-ray machine. C, Example of a digital panoramic system
12. PARTS OF PANORAMIC UNITS a. x-ray tube head b. head positioner: chin rest notched bite block forehead rest lateral head support c. exposure controls
13. X-RAY TUBE HEAD: • Similar to intraoral x-ray tube head • Each has a filament to produce electrons and a target to produce x-rays • Collimator is a lead plate with narrow vertical slit • Narrow x-ray beam emerges from collimator minimize patient exposure to radiation
1
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
brief description about CONTENTS Introduction Principles of panoramic imaging Image layer Panoramic machines Panoramic film Patient positioning Interpreting the panoramic imaging INDICATION Advantages Disadvantages Conclusion References
3. INTRODUCTION • Panoramic imaging also called pantomography is a technique for producing a single tomographic image of facial structures that includes both the maxillary and mandibular dental arches and their supporting structures . • This is a curvilinear variant of conventional tomography.
4. PRINCIPLES OF PANORAMIC IMAGE FORMATION • Patero and Numata - describe the principles of panoramic radiography • based on the principle of reciprocal movement of x-ray source and an image receptor around a central point or plane called the image layer, in which the OBJECT of image is located. • OBJECT in front or behind this image are not clearly captured because of their movement relative to the centre of rotation of the receptor and the x-ray source.
5. The film and x-ray tubehead move around the patient in opposite directions in panoramic radiography
6. ROTATION CENTER The pivotal point or axis around which the cassette carrier and tube head rotate is termed rotation center Three basic rotation center used in panoramic radiography Double centre rotation Triple centre rotation moving centre rotation The location and number of rotational centers INFLUENCE size and shape of focal trough
7. IMAGE LAYER • Also known as focal trough • It is a three dimensional curved zone where the structures lying within this layer are reasonably well defined on final panoramic image. • The structures seen on a panoramic image are primarily those located within image layer. • OBJECTSoutside the image layer are blurred magnified are reduced in size. Even distorted to the extent of not being recognizable. • This shape of image layer varies with the brand of equipment used.
8. FOCAL TROUGH
9. FACTORS AFFECTING SIZE OF IMAGE LAYER: Arc path Velocity of receptor and X-ray tube head Alignment of x-ray beam Collimator width The location of image layer change with extensive machine used so recalibration may be necessary if consistently suboptimal images are produced. As a position of object is moved within the image layer size and shape of image layer change.
10. PANORAMIC UNIT
11. A, Orthophos XG Plus extraoral x-ray machine. B, Orthoralix 8500 extraoral x-ray machine. C, Example of a digital panoramic system
12. PARTS OF PANORAMIC UNITS a. x-ray tube head b. head positioner: chin rest notched bite block forehead rest lateral head support c. exposure controls
13. X-RAY TUBE HEAD: • Similar to intraoral x-ray tube head • Each has a filament to produce electrons and a target to produce x-rays • Collimator is a lead plate with narrow vertical slit • Narrow x-ray beam emerges from collimator minimize patient exposure to radiation
1
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.
radiation physics is important to know for dental student to be able to utlize xray and to know the benefita and overcome the hazards of radiation. in this lecture history of discovery of xray and properties of xrays and properties of elecromagnetic waves. mechanism of xay production and parts of ddental xray machine morreover the factors affecting image quality is also discussed in details . diagrams and images are included for verification
LECTURE 14 ATOMIC STRUCTURE ELECTRONS, PROTONS and NEUTRONS.docxmanningchassidy
LECTURE 14 ATOMIC STRUCTURE: ELECTRONS, PROTONS and NEUTRONS
The above figure displays a cathode-ray tube (CRT). Today, a CRT is described as a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images. It modulates, accelerates, and deflects electron beams onto a screen tocreate the images. The images may represent electrical waveforms (in an oscilloscope), pictures (a television screen, computer monitor), radar targets, or other phenomena.
We now know that cathode rays are streams of electrons observed in discharge tubes. If an evacuated glass tube (upper image) is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow (lower image), due to electrons emitted from the negative cathode.
The above “official” account presupposes that one knows what an electron is and what are its physical properties (mass and charge). The discovery of the electron opened up a whole new chapter in the understanding of matter. This led to the realization that light and matter could not be fully understood using the classicallaws of physics, and that a totally different way of understanding nature was needed. Thus emerged, beginning in the last years of the 19th century, a completely new description of light and matter. This new description became known as quantum mechanics, and resulted in the quantum theory of atoms, molecules and the chemical bond. This is the historical journey on which we shall embark in this Lecture.
Cathode rays were discovered by Julius Plücker (1801-1868) and Johann Wilhelm Hittorf(1824-1914). Their experimental apparatus depended on two earlier inventions: 1) Volta’s battery; and, 2) a sealed glass tube in which a partial vacuum was maintained. The latter was invented by a German physicist and glassblower, Heinrich Geissler, in 1857.
Hittorf observed that some unknown rays were emitted from the cathode (negative electrode) which could cast shadows on the glowing wall of the tube, indicating the rays were traveling in straight lines. In 1890, Arthur Schuster demonstrated cathode rays could be deflected by electric fields, and William Crookes showed they could be deflected by magnetic fields.
It was these experiments on cathode rays inside the cathode ray tube that drew the attention of Röntgen. After repeating the above experiments, he began to study the radiation emitted outside the cathode ray tube, using fluorescent chemical sensors, e.g., barium platinocyanide, to detect radiation. His discovery of x-rays on November 8, 1895 was communicated to the Physico-Medical Society of Würzburg later in November, 1895. A translation of his paper appeared two months later on January 23, 1896 in the English journal, Nature. (You can dial up this article on Gallica and read it for yourself).
Paraphrasing Louis XV(1710 – 1774) of France, were he not such a humble, unassuming man,Röntgenmight have said "A.
Lecture 3 Facial cosmetic surgery
Maxillofacial Surgery
Dental Students Fifth Year second semester
Al Azhar University Gaza Palestine
Dr. Lama El Banna
https://twitter.com/lama_k_banna
Lecture 1 Facial cosmetic surgery
Maxillofacial Surgery
Dental Students Fifth Year second semester
Al Azhar University Gaza Palestine
Dr. Lama El Banna
https://twitter.com/lama_k_banna
Facial neuropathology Maxillofacial SurgeryLama K Banna
Lecture 4 facial neuropathology
Maxillofacial Surgery
Dental Students Fifth Year second semester
Al Azhar University Gaza Palestine
Dr. Lama El Banna
https://twitter.com/lama_k_banna
Lecture 2 Facial cosmetic surgery
Maxillofacial Surgery
Dental Students Fifth Year second semester
Al Azhar University Gaza Palestine
Dr. Lama El Banna
https://twitter.com/lama_k_banna
Lecture 12 general considerations in treatment of tmdLama K Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name 12 general considerations in the treatment of TMJ
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Maxillofacial Surgery
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Lecture Name TMJ temporomandibular joint
Lecture 10
Al Azhar University Gaza Palestine
Dr. Lama El Banna
https://twitter.com/lama_k_banna
Lecture 11 temporomandibular joint Part 3Lama K Banna
Maxillofacial Surgery
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Lecture Name TMJ temporomandibular joint Part 3
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Al Azhar University Gaza Palestine
Dr. Lama El Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name TMJ anatomy examination 2
Lecture 9
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Lecture 7 correction of dentofacial deformities Part 2Lama K Banna
Maxillofacial Surgery
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Lecture Name Correction of dentofacial deformities Part 2
Lecture 7
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Lecture 8 management of patients with orofacial cleftsLama K Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name management of patients with orofacial clefts
Lecture 8
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Lecture 5 Diagnosis and management of salivary gland disorders Part 2Lama K Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name Salivary gland 2
Diagnosis and management of salivary gland disorders Part 2
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Lecture 6 correction of dentofacial deformitiesLama K Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name Correction of dentofacial deformities
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Al Azhar University Gaza Palestine
Dr. Lama El Banna
lecture 4 Diagnosis and management of salivary gland disordersLama K Banna
Maxillofacial Surgery
Dental Students Fifth Year First semester
Lecture Name Salivary gland
Diagnosis and management of salivary gland disorders
Al Azhar University Gaza Palestine
Dr. Lama El Banna
Maxillofacial Surgery 1
Dental Students Fifth Year First semester
Lecture Name maxillofacial trauma Part 3
Al Azhar University Gaza Palestine
Dr. Lama El Banna
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Lecture Name maxillofacial trauma part 2
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Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
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These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
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Oral radiology lecture 1
1. Oral Radiology
Dr.Rawand Samy Mohamed Abu Nahla
Oral Medicine,periodontology&oral Radiology
Department.
Dr. Haydar.A.Shafy Faculity Of Dentistery.
El Azhar University.
2. Scientific Content Of Subject Curricula:
1. Radiation history.
2. Radiation physics.
3. Dental x-ray image characteristics.
4. Image receptors.
5. Introduction to radiographic examination.
6. Exposure and technique errors.
7. Processing of x-ray films.
8. Normal anatomical landmarks.
9. Radiation protection.
10. Biological effects of radiation.
3. 11. Extra-oral radiography.
12. Panoramic radiography.
13. Alternative and specialized techniques.
14. The periapical tissues.
15. Interpretation of dental caries.
16. Interpretation of periodontal diseases.
17. Radiological differential diagnosis describing a lesion.
18. Differential diagnosis of radiolucent lesions of the jaws.
19. Differential diagnosis of radiopaque lesions of the jaws.
20. Cysts of the jaws.
21. Benign tumors of the jaws.
22. Malignant tumors of the jaws.
23. Trauma of teeth and facial structures.
24. The temporomandibular joint.
25. Bone diseases of radiological importance.
26. Disorders of salivary glands and sialography.
6. The Discovery
On November 8th, 1895, Wilhelm Conrad Roentgen was working
in his laboratory in Wurzburg, Germany, using Crooke’s tubes.
In the darkened laboratory, he noticed that a sheet of cardboard,
placed several feet away, was glowing in the shape of the letter A
that a student had painted in liquid Barium platinocyanide.
He noticed that the effect was fluorescent, that is, the glow stopped
if the current was interrupted or the rays were blocked. Further, he
discovered that different materials attenuated the beam differently.
7. Roentgen then isolated himself in his laboratory for the next
seven weeks. From his carefully crafted experiments, much of
what is known about the physics of x-radiation was derived. He
worked in secrecy, afraid that others might publish their results
before him. It has also been postulated that he worked alone
because he did not wish to be ridiculed if he were wrong.
8. In those seven weeks, Roentgen discovered that:
• Although the new rays were invisible, they caused fluorescence in certain
substances
• They darkened photographic plates
• They were propagated in straight lines
• Their behavior differed fundamentally from that of cathode rays
• They were neither reflected nor refracted by (then known) experimental methods
• They were not deviated by the influence of electro-magnetic fields
9. • Air traversed by the rays was made electrically conductive.
• He investigated the startling penetration of the rays through many materials and
observed the "hardening" of x-ray beams after penetrating several absorbers.
• He noted that different types of scattered and of secondary radiations were
produced.
Source: http://compepid.tuskegee.edu/syllabi/clinical/small/radiology/chapter2
10. On December 28th, 1895,Roentgen presented his findings to the Wurzburg Physical-Medical Society.
He presented several radiographs, including the one of his wife’s hand. By January 1896, words of his
discovery had spread throughout the world.
Enter Dentistry
In January 1896, a dentist in Braunschweig, Germany made the first dental
radiograph. Using a glass photographic plate wrapped in black rubber dam
and with an exposure of 25 minutes.
Dr. Otto Walkoff produced this intraoral radiograph
11. This radiograph was made on February 1st,
1896 by Dr. Walter Konig of Germany (Fig.1).
Dr Kells used impression compound to
stabilized the film during exposure (Fig.2).
Fig.2
Fig.1
12. It is thought that the first dental radiograph made in the United States was by Dr. Edmund Kells of
New Orleans, Louisiana.
Roentgen’s Apparatus
Roentgen originally used a variation on the Hittorf-Crooke’s tube, developed by Philipp Lenard.
Lenard placed a small window of thin aluminum foil over an opening in the tube.
This allowed the cathode rays to escape the tube more readily, as the current was applied.
The surprise was that the fluorescent effect occurred while using the heavier-walled Hittorf-Crooke’s
tube.
15. Roentgen’s Apparatus:
Cathode Ray:
Cathode rays are streams of electrons observed in vacuum tubes, i.e. evacuated glass tubes
that are equipped with at least two electrodes, a cathode (negative electrode) and an anode
(positive electrode) in a configuration known as a diode When the cathode is heated, it emits
some radiation which travels to the anode. If the inner glass walls behind the anode are
coated with a phosphorescent material, they glow. A metal shape placed between the
electrodes casts a shadow on the glowing coating. This suggested that the cause of the light
emission was comprised of rays emitted by the cathode and hitting the coating. They travel
towards the anode in straight lines, and continue past it for some distance.
16. Cathode Ray Tubes:
The Cross Vacuum Scale demonstrates the phenomenon of discharge
at different pressures(vacuum) inside the tubes. The pressures varies
between 40 Torr (mmHg) lowest vacuum (left tube) to 0.03 Torr, the
highest vacuum (right tube.)
In this high vacuum, used in many Crookes tubes, X-Rays are
produced.
The glass emits here a green glow.
17. On February 22nd, 1890 in Philadelphia, PA, A.W. Goodspeed and William
Jennings produced this radiogram by placing the coins on top of a glass photographic
plate.
The coins and plate were exposed to radiation via a Hittorf – Crooke’s tube.
They had realized the significance of their findings, they would have beaten Roentgen
to the discovery of X-rays by more than 5 years. Additionally, early radiographs might
have be called “good speedograms.” This proves that sometimes things are better off
as they are!
18. Contemporaries
Lenard also experimented, with Hittorf – Crooke’s
tubes and, undoubtedly, produced X-rays, but did immediately grasp the
importance of the finding.
He resented Roentgen throughout his life.
In 1933 he joined the National Socialist Party(Nazis.)
He rose to the rank of Chief of Aryan Physics.
Philipp
vonLenard
1862 – 1947
19. Heinrich
Rudolf Hertz
1857-1894
From 1885 to 1889 Hertz became the first person
to broadcast and receive radio waves, and to
establish the fact that light was a form of
electromagnetic radiation.
Experimented with cathode rays. (Gugliemo
Marconi didn't begin his own wireless experiments
until 1894, based on the earlier work of Hertz,
Maxwell, and others.) Hertz probably would have
gone on to make many more scientific contributions,
but he died quite young, less than a month before
his 37th birthday.
20. Timeline Leading to Roentgen’s Discovery:
300 Years of Discoveries Leading to Roentgen’s Work
• 1600 Gilbert's (1540-1603) De Magnete created the foundation for the sciences of magnetism and
electricity.
• 1675 Newton (1643-1727) built a more efficient electrostatic generator with a rotating glass sphere.
• 1729 Gray (1696-1736) distinguished conductors of electricity from nonconductors.
• 1750 Franklin (1706-1790) defined positive and negative electricity.
• 1785 Morgan (?-1785) in vacuum experiments, possibly produced x-rays.
• 1800 Volta (1745-1827) constructed the first electrical battery, the Voltaic pile.
• 1820 Oersted (1777-1851) discovered the link between electricity and magnetism.
• 1827 Ohm (1787-1854) formulated Ohm's law, stating the relation between electric current,
electromotive force, and resistance.
21. • 1821 Faraday (1791-1867) and Henry (1797-1878) discovered electromagnetic induction.
• 1850 Plucker (1801-1868) observed green-glass fluorescence opposite the negative electrode in a
vacuum tube.
• 1860 Toepler, Holtz, and Wimshurst improved electrostatic machines.
• 1873 Maxwell (1831-1879) published his famous equations in the book, "Treatise on Electricity
and Magnetism ."
• 1879 Crookes (1832-1919) found that cathode rays can be deflected by a magnet, and believed
that he was dealing with "a fourth state of matter."
22. • 1892 Lenard (1862-1947) built improved cathode-ray tubes and made
important observations on the properties of cathode rays.
• 1893 J. J. Thomson (1856-1940) published a supplementary volume to
Maxwell's treatise, describing in detail the passage of electricity through gases.
Source: http://compepid.tuskegee.edu/syllabi/clinical/small/radiology/chapter2.html
24. William Morton (1845-1920)
• New York dentist
• Also credited (along with Kells) with the first dental radiograph exposed in the United
States
• Wrote a book on X-rays in 1896
William H. Rollins (1852-1929)
• Boston Dentist
• Publish more than 200 articles on radiation effects and safety between 1896 and1904
• "Notes on X-Light", published in 1904 called for radiation protection for radiation
workers and patients
25. The Rollins Collimator
Image from the Radiology Centennial Collection
This collimator is the forerunner of our rectangular collimators!
William H. Rollins
• Alas, Rollins was ignored by his colleagues, much to their detriment. It was not until atomic bombs were exploded
over Hiroshima and Nagasaki that dentistry took
a serious look at radiation safety.
26. Dr. Frank Van Woert (1856-1927)
Dr. Van Woert was another pioneer of oral and maxillofacial radiology. He made a
practical demonstration of dental radiography before the NewYork Odontological
Society in1897. He was one of the first to use Kodak film (instead of glass plates).
These were wrapped in rubber dam and held in place with compound. He later
invented a metal film holder, an improved bisecting angulator, an automatic
timing switch, and the daylight processing tank.
Dr. Frank Van Woert
(1856-1927)
27. Howard Riley Raper (1886-1978)
Dr. Raper had one of the first oral and maxillofacial radiology offices (as opposed to a laboratory).
He was the inventor of the bitewing radiograph in 1924, the first to introduce oral and
maxillofacial radiology into the dental curriculum (in 1910 at the Indiana Dental School), and the
first to write a textbook on the subject (Elementary and Dental Radiology, 1913).
Howard Riley Raper
(1886-1978)
28. Early dental x-ray unit
• The G.E. CDX was the first modern type dental x-ray unit on the market in 1921.
Others soon followed.
Early dental x-ray unit
• Picker dental unit from the 1930’s
29. The Dangers
Although many had noted difficulties associated with "X-ray burns," it was not until
the death of Clarence Dally (1865- 1904), Edison's longtime assistant in X-ray
manufacture and testing, that observers finally agreed that the magic rays could kill as
well as cure.
Image from the Radiology Centennial Collection
30. The Dangers
Dr. Edmund Kells, an early pioneer of oral radiology, paid a tragic price for his work. When, at
age 40, he first began his work with X-rays, he was unaware of the unseen danger of cumulative
doses of radiation. He often held the films in place with his own fingers. By the time Kells
reached 50, he had developed cancer in his right hand.
Over the next 20 years, Kells endured 42 operations. He lost, progressively, his hand, his arm, and
his shoulder.
31. In spite of agonizing pain, 42 operations, and numerous skin grafts, his 20-year battle against
the ill effects of the exposure from dental X-rays was about to come to an end.
Throughout the trauma, Kells still served the profession. He lectured on preventive dentistry
and the conservation of teeth. He wrote books, and he contributed over 150 articles to
dental journals. At last, however, Kells suffering became intolerable. On May 7, 1928, at age
72, he committed suicide.
Source:http://www.ac.cc.md.us/dental/98-1newsletter/EdmundKells.html
http://clarionherald.org/20000427/
32. Röntgen had family in the United States (in Iowa) and at one time he planned to emigrate. Although
he accepted an appointment at Columbia University in New York City and had actually purchased
transatlantic tickets, the outbreak of World War I changed his plans and he remained in Munich for the
rest of his career.
Röntgen died in 1923 of carcinoma of the bowel. It is not believed his carcinoma was a result of his
work with ionizing radiation because his investigations were only for a short time and he was one of the
few pioneers in the field who used protective lead shields routinely.
Source: http://en.wikipedia.org/wiki/Wilhelm_R%C3%B6ntgen#Early_life_and_education
33. Roentgen published a total of 3 papers on x-rays between 1895 and 1897. None
of his conclusions have yet been proven false.
Source:
http://en.wikipedia.org/wiki/Wilhelm_R%C3%B6ntgen
#Early_life_and_education
Image from the Radiology Centennial Collection