The linear accelerator uses electromagnetic waves to accelerate charged particles like electrons to high energies through a linear tube. The electron beam can treat superficial tumors directly or produce x-rays by striking a target to treat deep tumors. X-ray therapy has evolved from low energy Grenz rays and contact therapy for superficial tumors to higher energy orthovoltage, supervoltage, and megavoltage therapy using linear accelerators and cobalt-60 units that can treat deeper tumors. The main advantage of linear accelerators is that particles can reach very high energies without extremely high voltages, though each accelerating segment is only used once requiring longer linacs for higher energies.
Radionuclide's such as radium-226, cesium-137, and cobalt-60 have been used as sources of gamma rays for teletherapy. These gamma rays are emitted from the radionuclide's as they undergo radioactive disintegration. Of all the radionuclide's, Co-60 has proved to be the most suitable for external beam radiotherapy.
Radionuclide's such as radium-226, cesium-137, and cobalt-60 have been used as sources of gamma rays for teletherapy. These gamma rays are emitted from the radionuclide's as they undergo radioactive disintegration. Of all the radionuclide's, Co-60 has proved to be the most suitable for external beam radiotherapy.
Brolis Semiconductors: Targeting Spectroscopy with Antimonide SourcesKristijonas Vizbaras
Featured article about cutting edge infrared technology in Compound Semiconductor November/December Issue 2015. Mass-market potential and production issues addressed.
this is to present basic functional principles of high frequency x-ray generators. The emphasis is put on physical concepts that determine the engineering solutions to the problem of efficient generation and control of high voltage power required to drive the x-ray tube. The physics of magnetically coupled circuits is discussed first, as a background for the discussion of Study related to high-frequency power transformer design by X-ray Generator.
Produces radiation that is referred to as a high-energy x-ray for patients with cancer In 1928, RWideroe demonstrated that electrons could be accelerated through a tube by applying a radio frequency voltage to sections of the tubeThe linear accelerator is an extension of Wideroe’s ideaThe name ‘linear accelerator’ comes from the fact that electrons are produced in the machine and accelerated in a straight line.
Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
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.
Brolis Semiconductors: Targeting Spectroscopy with Antimonide SourcesKristijonas Vizbaras
Featured article about cutting edge infrared technology in Compound Semiconductor November/December Issue 2015. Mass-market potential and production issues addressed.
this is to present basic functional principles of high frequency x-ray generators. The emphasis is put on physical concepts that determine the engineering solutions to the problem of efficient generation and control of high voltage power required to drive the x-ray tube. The physics of magnetically coupled circuits is discussed first, as a background for the discussion of Study related to high-frequency power transformer design by X-ray Generator.
Produces radiation that is referred to as a high-energy x-ray for patients with cancer In 1928, RWideroe demonstrated that electrons could be accelerated through a tube by applying a radio frequency voltage to sections of the tubeThe linear accelerator is an extension of Wideroe’s ideaThe name ‘linear accelerator’ comes from the fact that electrons are produced in the machine and accelerated in a straight line.
Title: Sense of Taste
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 structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
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.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
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.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
2. • The linear accelerator (linac) is a device that uses high-
frequency electromagnetic waves to accelerate charged
particles such as electrons to high energies through a
linear tube.
• The high-energy electron beam itself can be used for
treating superficial tumors, or it can be made to strike a
target to produce x-rays for treating deep-seated tumors
4. EVOLUTION OF X-RAY THERAPY:
GRENZ RAY THERAPY:
The term Grenz ray therapy is used to describe treatment
with beams of very soft (low-energy) x-rays produced at
potentials below 20 kV.
Because of the very low depth of penetration such radiations
are no longer used in radiation therapy.
5. CONTACT THERAPY:
A contact therapy or endocavitary machine operates at potentials of
40 to 50 kV and facilitates irradiation of accessible lesions at very
short source to surface distances (SSDs).
The machine operates typically at a tube current of 2 mA.
Applicators available with such machines can provide an SSD of
2.0 cm or less.
6. When this beam is incident on a patient, the skin surface is
maximally irradiated but the underlying tissues are spared to an
increasing degree with depth.
This quality of radiation is useful for tumors not deeper than 1 to
2 mm. The beam is almost completely absorbed with 2 cm of soft
tissue. Endocavitary x-ray machines have been used in the
treatment of superficial rectal cancers.
7. SUPERFICIAL THERAPY:
The term superficial therapy applies to treatment with x-rays produced at
potentials ranging from 50 to 150 kV. Varying thicknesses of filtration
(usually 1- to 6-mm aluminum) are added to harden the beam to a
desired degree.
The superficial treatments are usually given with the help of applicators
or cones attachable to the diaphragm of the machine. The SSD typically
ranges between 15 and 20 cm. The machine is usually operated at a
tube current of 5 to 8 mA.
8. Superficial beam of the quality shown is useful for irradiating
tumors confined to about 5-mm depth (~90% depth dose).
Beyond this depth, the dose drop-off is too severe to deliver
adequate depth dose without considerable overdosing of the
skin surface.
9. ORTHOVOLTAGE THERAPY:
The term orthovoltage therapy, or deep therapy, is used to describe
treatment with x-rays produced at potentials ranging from 150 to 500
kV.
Most orthovoltage equipment is operated at 200 to 300 kV and 10 to
20 mA.
The maximum dose occurs close to the skin surface, with 90% of
that value occurring at a depth of about 2 cm.
Thus, in a single-field treatment, adequate dose cannot be delivered
to a tumor beyond this depth.
10. Severe limitations to the use of orthovoltage beam in treating
lesions deeper than 2 to 3 cm.
The greatest limitation is the skin dose, which becomes
prohibitively large when adequate doses are to be delivered to
deep- seated tumors.
Increased absorbed dose in bone and increased scattering that
make orthovoltage beams unsuitable for the treatment of tumors
behind bone.
11. SUPER-VOLTAGE THERAPY:
X-ray therapy in the range of 500 to 1,000 kV has been
designated as high- voltage therapy or supervoltage therapy
Major problem is insulating the high-voltage transformer.
12. MEGAVOLTAGE THERAPY:
X-ray beams of energy 1 MV or greater can be classified as
megavoltage beams.
Although the term strictly applies to x-ray beams, γ-ray beams
produced by radionuclides are also commonly included in this
category if their energy is 1 MeV or greater.
13. Examples of clinical megavoltage machines are
accelerators such as
• Van de Graaff generator,
• linear accelerator,
• betatron and microtron,
• teletherapy γ-ray units such as cobalt-60.
14.
15. CO-60 TELETHERAPY UNIT:
Cobalt 60 teletherapy units appear similar to early generation
clinical linear accelerators.
Most feature a rotating gantry and variable jaw collimation
located in the treatment head.
A light field and optical distance indicator is incorporated into
the treatment head to facilitate patient alignment.
Most Co-60 units use a source-to-axis-distance of 80cm
which compensates for the lower output as compared with a
linear accelerator.
16. When not in use, the source is stored in a heavily shielded
compartment of the treatment head.
Activation and deactivation of the beam is accomplished
by mechanically or pneumatically moving the source from
its shielded storage space to the treatment position
17. The major problem with these units is the
-decaying source, the source needs to be replaced every 5-7 years and is
becoming more and more expensive and is also hard to get.
-reduced output resulting in increased treatment times which in turn will
effectively reduce the patient output.
-Disposal of spent source is another major problem
-the dose-rate is determined by the amount of cobalt source in the machine
and cannot be regulated.
-the edges of the beam are less sharply defined- less precision in dose
delivery.
18. ADVANTAGES OF CO-60 UNIT OVER LINAC:
-lower capital and installation cost
-lower servicing and maintenance
-lesser dependance on reliable electric power
-simplicity of design
-ease of operation
57. GANTRY:
Source of radiation can rotate about a horizontal axis.
As the gantry rotates, the collimator axis (supposedly
coincident with the central axis of the beam) moves in a
vertical plane.
The point of intersection of the collimator axis and the
axis of rotation of the gantry is known as the isocenter
58.
59. MECHANICAL ISOCENTRE:
Point about which the Linac and the couch rotate
RADIATION ISOCENTRE:
Point where the radiation beams intersect when the
gantry, collimeter or couch are rotated
Ideally these two points are one and the same
60.
61. The main advantage of linear accelerators is that the
particles are able to reach very high energies without the
need for extremely high voltages.
The main disadvantage is that, because the particles travel
in a straight line, each accelerating segment is used only
once. This means that the only way of achieving particle
beams with even higher energy is to undertake the expense
of adding segments to the length of the linac.