Fundamentals of Imaging. This course will provide you with the principles involved in the formation and recording of the radiologic image in both conventional and digital imaging systems as well as the principles of image quality assessment.
Part 4
Intensifying screens are major component of the image receptor used in conventional radiography.Its function is to convert the X-rays into visible light through the process of fluorescence.
IT REVIEWS Introduction and definition INTRODUCTION
BEAM-RESTRICTING DEVICES
ADVANTAGES AND DISADVANTAGES
TECHNIQUE
FILTERS
AND PHYSICS BEHIND IT AND LIGHT AND MIRROR ARRANGMENT CLEARLY EXPLAINED WELL.IT ALSO INCLUES THE FLITERS CLASSIFICATION AND COLLIMATORS CLASSIFICATION.
COLLIMATIORS ARE NOTHING BUT BEAM ALINERS
Fundamentals of Imaging. This course will provide you with the principles involved in the formation and recording of the radiologic image in both conventional and digital imaging systems as well as the principles of image quality assessment.
Part 4
Intensifying screens are major component of the image receptor used in conventional radiography.Its function is to convert the X-rays into visible light through the process of fluorescence.
IT REVIEWS Introduction and definition INTRODUCTION
BEAM-RESTRICTING DEVICES
ADVANTAGES AND DISADVANTAGES
TECHNIQUE
FILTERS
AND PHYSICS BEHIND IT AND LIGHT AND MIRROR ARRANGMENT CLEARLY EXPLAINED WELL.IT ALSO INCLUES THE FLITERS CLASSIFICATION AND COLLIMATORS CLASSIFICATION.
COLLIMATIORS ARE NOTHING BUT BEAM ALINERS
Messaging Brokers are intrinsic part of our infrastructure and our experience with HornetQ has not been really great.
We have experienced issues that forced us to perform restarts multiple times a day and sometimes they weren't sufficient to fix the issue and data cleanup was needed resulting in loss of important messages.
Lack of documentation, lack of proper support and lack of stability of HornetQ broker are some of the reasons for looking into new Messaging Brokers.
During this session I will present the path we have taken to Prioritize Features -> Compare Brokers -> Eliminate -> Benchmark and the findings together with recommendations.
This task resulted in implementation of generic messaging broker benchmarking tool in Java, called Benchmark.io which we are intending to open source.
Presenting a presentation on the topic of Column chromatography with including basics of chromatography, principles, equations, graphs and data related to it.
Topics which covered in this ppt is
Principle of chromatography
classification of chromatography
partition coefficient
chromatogram
Resolution
plate theory
determination of N
band zone broadening
rate theory
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Preeti Choudhary
MAGNETIC RESONANCE ANGIOGRAPHY (MRA).pptxRohit Bansal
MAGNETIC RESONANCE ANGIOGRAPHY (MRA) AND MAGNETIC RESONANCE SPECTROSCOPY (MRS) ARE DESCRIBED IN DETAILIN THIS PPT. CONTENT TAKEN FROM MUTIPLE BOOKS AND GENERALS.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
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
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
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
2. TOPICS INCLUDED :
•BASIC OVERVIEW OF X-RAY BEAM
•SCATTERED RADIATION & ITS TYPES
•BEAM LIMITING DEVICES
•BEAM CENTERING DEVICES
•GRIDS
3. BASIC OVERVIEW OF X-RAY BEAM
• X-RAY belongs to a group of radiation known as the
(ELECTROMAGNETIC RADIATIONS)
• All the electromagnetic radiations have dual
characteristics
• 1- Wave nature
• 2- Particle nature
• These are electromagnetic wave of high energy and
very short wavelength, which is able to pass through
many materials .
4. WAVELENGTH OF X RAY
Wavelength of X-RAY - 10−8 to 10−12 metre
Frequency ranges from -1016 to 1020 hertz (Hz)
5. SCATTERED RADIATION
• When useful beam interact with objects and then some of the
radiation reflects back that results in the production of
secondary beam called as scattered radiation
6. 1. OVERVIEW OF SCATTERING
•Scattering is mainly of 5 types
• Coherent scattering
• Compton scattering
• Photoelectric effect ( Mostly used in diagnostic
work)
• Photo disintegrating
• Pair productions
7. DISADVANTAGES OF
SCATTERED RADIATION :
• Basically, when X-RAY are penetrated then they cease to exit but
when they are scattered then they are deflected from there original
path and hence carry no useful information…
• At the end they only add up NOISE .
• And adds up the unwanted dose to the peoples present in the X-
RAY room .
• The end result is that the radiographic image is of a poor quality
which makes it difficult to diagnose it. Contrast of the film is also
degraded.
9. MOST COMMON SOLUTION TO
DECREASE THE SCATTERED
RADIATION
• Filters
• Aperture diaphragms
• Cones and cylinders
• Collimators
• Beam centring devices
• Radiographic Grids
• Various devices used to reduce scattered radiation
10. FILTERS & FILTRATION
• FILTERS ARE THE DEVICES USED TO
ATTENUATE OR RESTRICTING THE BEAM
OF XRAY
• FILTRATION IS BASICALLY THE PROCESS
OF ATTENUATING OR SHAPING THE X -RAY
BEAM TO INCREASE THE AMOUNT OF
USEFUL PHOTONS AND DECREASE THE
LOW ENERGY PHOTONS SO THAT WE CAN
GET AN IMAGE WITH BETTER CONTRAST
• (FOR EXAMPLE – A STRAINER IS USED FOR
THE SEPARATION OF TEA PARTICLES AND
THE TEA )
• THIS ALSO DECREASE THE PATIENT
RADIATION DOSE AND OCCUPATIONAL
HAZARDS
• QUALITY OF X-RAY SPECTRUM SHIFTS TO
THE HIGHER ENERGY
11. HOW FILTRATION WORK
• W H E N E X P O S U R E I S D O N E T H E N B O T H H I G H A S W E L L
A S L O W E N E R G Y X - R AY P H O T O N S A R E P R O D U C E D .
• W H E N T H E S E X - R AY P H O T O N S I N T E R A C T W I T H T H E
H U M A N B O D Y, O N LY T H E H I G H E N E R G Y P H O T O N S
P E N E T R AT E W H I L E T H E L O W E N E R G Y P H O T O N S G E T
A B S O R B E D I N T H E B O D Y, H E N C E I N C R E A S I N G T H E
PAT I E N T R A D I AT I O N D O S E .
• F I LT R AT I O N B A S I C A L LY A B S O R B S T H E L O W E N E R G Y
P H O T O N S F R O M T H E B E A M A N D H E N C E I N C R E A S E S T H E
I M A G E C O N T R A S T.
12.
13. LEVEL OF FILTRATION
• INHERENT FILTRATION
( X-RAY TUBE AND ITS HOUSING )
• ADDED FILTRATION
(SHEET OF METAL PIECE PLACED IN
THE PATH OF BEAM
• TOTAL FILTRATION
( TOTAL FILTRATION = INHERENT
FILTRATION + ADDED FILTRATION )
14. INHERENT FILTRATION
• THE ABSORPTION OF THE LOW ENERGY
X-RAY PHOTONS BY THE X-RAY TUBE
COMPONENTS ITSELF IS KNOWN AS THE
INHERENT FILTRATION.
• A GLASS HOUSING, METAL ENCLOSURE
AND THE ASSEMBLY OIL IS
RESPONSIBLE FOR INHERENT
FILTRATION.
15. CONT…
• BUT DISADVANTAGE OF INHERENT
FILTRATION IS THAT IT CAUSES A
SIGNIFICANT REDUCTION IN THE IMAGE
CONTRAST.
• AT SOME PLACES WHERE UNFILTERED X -
RAY BEAM IS REQUIRED THERE
BERYLLIUM FILTERS ARE MOSTLY USED.
16.
17. ADDED FILTRATION
• A D D E D F I LT R AT I O N I S A R E S U LT O F A N Y B E A M
A B S O R B E R W H I C H I S P L A C E D I N T H E PAT H O F T H E X -
R AY B E A M , T H I S A B S O R B E R A B S O R B S T H E L O W O R
H I G H E N E R G Y P H O T O N S .
• T H I C K N E S S O F F I LT E R
B E L O W 5 0 K V P - 0 . 5 M M
5 0 - 7 0 K V P – 1 . 5 M M
A B O V E 7 0 - 2 . 5 M M )
• S O L U T I O N - W E A LWAY S U S E A D D E D F I LT E R S
M O S T LY I N A G R O U P O F A L U M I N I U M ( 1 3 ) +
C O P P E R ( 2 9 ) .
18. • T H E Y A R E A R R A N G E D A S T H E H I G H AT.
N O . ( C O P P E R )
E L E M E N T FA C E S T H E X - R AY T U B E W H I L E T H E
O T H E R ( A L U M I N I U M ) O N E FA C E S T H E PAT I E N T.
• M O S T O F T H E F I LT R AT I O N I S D O N E B Y C O P P E R .
• T H E Y C A N ' T B E U S E D S E PA R AT E LY.
• PAT I E N T R A D I AT I O N D O S E A S W E L L A S T H E I M A G E
C O N T R A S T I S R E D U C E D .
• T H I S C O M B I N AT I O N O F T W O L AY E R S O F F I LT E R S
I S A L S O K N O W N A S C O M P O U N D F I LT E R S .
CONT…….
19.
20. TOTAL FILTRATION
• TOTAL FILTRATION REFERS TO THE SUM OF THE BOTH FILTRATION
DONE BY INHERENT FILTER & ADDED FILTER
SOME OTHER FILTERS ARE
ALSO COMMONLY USED ARE
:
• WEDGE FILTER
• K-EDGE FILTER
21. WEDGE FILTER
• Wedge filters are mostly used at places where the body
part to be radiographed varies greatly in densities.(thick
from one side and thin from another side)
• Wedge filters are like the shape of a wedge, the thin part is
placed under thick body part while thick part is placed
under thin body part.
• Result is that ,beam attenuation by thick part is more
hence less radiation reaches the part and beam
attenuation by thin part is less hence more radiation
reaches thick part.
• Therefore a radiograph of uniform density is got.
22. EG : DURING SPINE WHERE SPINE DENSITY VARY GREATLY
SO WEDGE FILTERS ARE USED
Real image of wedge filter
23. THICKNESS OF FILTER
• More will be the thickness of filters more will
be the attenuation of X-RAY by it.
• In other words;-
• ATTENUATION 0< FILTER
THICKNESS
24. K-EDGE FILTERS
• FILTERS WITH METALS OF
HIGH ATOMIC NUMBER.
• USUALLY USED WITH X-RAY
TUBES OF HIGH CAPACITY AND
HIGH SPEED INTRIGUING
SCREEN.
• THESE FILTERS BASICALLY
USE THE K-EDGE ABSORPTION
OF ELEMENT
26. A P E R T U R E D I A P H R A G M S
• T H E S E A R E B A S I C A L LY T H E S I M P L E S T X - R AY B E A M
R E S T R I C T O R S .
• I T I S M A D E O F A S H E E T O F L E A D W H I C H I S H AV I N G A
H O L E AT I T S C E N T R E .
• I T S A D VA N TA G E I S I T S S I M P L I C I T Y, I T C A N B E A LT E R E D
T O A N Y S H A P E O R S I Z E B E C A U S E L E A D I T I S S O F T.
• I T S D I S A D VA N TA G E I S T H AT I T P R O D U C E S A FA I R LY
L A R G E P E N U M B R A ( U N E X P O S E D A R E A O R S H A D O W )
• P E N U M B R A C A N B E R E D U C E D B Y P L A C I N G T H E
D I A P H R A G M FA R AWAY F R O M T H E X - R AY T U B E .
• T H E C E N T R E O F T H E X - R AY F I E L D I S E X P O S E D B Y T H E
C I R C U L A R A R E A .
28. C O N E S A N D C Y L I N D E R S
• THESE RESTRICTORS ARE THE SHAPE OF CONES
AND CYLINDERS.
• THEY REDUCE THE UNEXPOSED AREA AT EDGES
BY REDUCING PENUMBRA
• THE FLARE OF THE CONE IS SIMILAR TO THE
GEOMETRIC SHAPE OF THE X-RAY BEAM, BUT IT
IS GREATER THAN THE FLARE OF THE X-RAY
BEAM.
• THEY ARE ATTACHED TO THE FRONT OF THE X -
RAY TUBE AND MAY ALSO BE EQUIPPED WITH
EXTENSIONS TO GIVE EVEN BETTER
RESTRICTION.
30. ADVANTAGES
• INEXPENSIVE
• SIMPLE TO USE
• REDUCE PENUMBRA AND
OR FOCAL RADIATION
• PROVIDE BETTER BEAM
RESTRICTION AT A
GREATER DISTANCE AT A
FOCAL SPOT
DISADVANTAGE
• FIXED VIEWING AREA
• FLARED CONES ARE NO
BETTER AT REDUCING
PENUMBRA THAN
APERTURE DIAPHRAGMS
32. C O L L I M AT O R S
C OLLIMATOR S AR E C ON SID ER ED TH E BEST BEAM
R ESTR IC TOR D EVIC ES.
IT IS HAVING TWO ADVANTAGES:
- IT PR OVID ES AN IN FIN ITE VAR IETY OF R EC TAN GU LAR
X- R AY FIELD S.
- IT ALSO SHOWS THE CENTRE POINT OF THE X - RAY
BEAM.
IT C ON SISTS OF TW O SETS OF SH U TTER S ( S1 & $2)
W H IC H MOVE IN OPPOSITE D IR EC TION S TO R EMOVE
TH E PEN U MBR A PR OD U C ED BY EAC H OTH ER .
35. GRIDS
GRIDS WERE INVENTED BY DR GUSTAVE BUCKY
IN 1913.
GRIDS ARE USED TO DECREASE THE
SCATTERED RADIATION.
GRIDS BASICALLY CONSISTS OF LEAD STRIPS
&
INTERSPACING MATERIAL (INTERSPACE IS
MADE UP OF
ORGANIC MATERIAL OR ALUMINIUM)
WHICH IS ALIGNED WITH THE GEOMETRY OF X -
RAY BEAM OF A PARTICULAR TUBE.
38. GRID RATIO
• GRID RATIO IS DEFINED AS THE RATIO OF THE
HEIGHT OF THE LEAD STRIPS TO THE DISTANCE
BETWEEN THE LEAD STRIPS.
• GRID RATIO IS ALWAYS EXPRESSED AS E.G.
8:1(WHERE 8 IS THE ACTUAL RATIO AND THE
SECOND NO. IS ALWAYS ONE).
• IN RADIOLOGICAL GRIDS OF RATIO BETWEEN 4:1
TO 16:1
ARE GENERALLY USED.
• USUALLY THE THICKNESS OF LEAD STRIPS IS
ABOUT
O.05MM.
39.
40. GRID PATTERNS / GRID TYPES
ON THE BASIS OF
MOVEMENT:
• STATIONARY GRID.
• AKA "Wafer" grids
• Produce x-rays that have very fine white
lines on them. These are the area of the
film that are blocked from receiving any
x-ray by the lead strips.
• To eliminate these grid lines" the
moving grid or Potter-Bucky diaphragm
was developed by Potter in 1913.
MOVING GRID
• THESE ARE THE
MODIFIED FOR OF
STATIONARY GRID
WITH A MOTOR
ATTACHED WITH THEN
WHICH ROTATE OR
MAKE THEM MOVE
ARE MOVING GRIDS
41.
42. TYPES OF GRIDS
B A S I C A L LY T H E R E A R E T H R E E T Y P E S O F G R I D O N
T H E B A S I S O F S T R I P PAT T E R N :
1 - L I N E A R G R I D / PA R A L L E L G R I D
2 - C R O S S E D G R I D
3 - F O C U S E D G R I D
L I N E A R G R I D I S A G R I D I N W H I C H T H E L E A D S T R I P S
A R E P L A C E D PA R A L L E L TO E A C H O T H E R .
I T S A D VA N TA G E I S T H AT W H E N U S I N G L I N E A R G R I D
, T H E N W E C A N A N G L E T H E T U B E A L S O .
C R O S S E D G R I D I S F O R M E D W H E N T W O L I N E A R
G R I D S A R E O V E R L A P P E D W I T H E A C H O T H E R . I T
C A N N O T B E U S E D W I T H O B L I Q U E T E C H N I Q U E S .
43.
44. FOCUSED GRID
• A FOC U SED GR ID IS A GR ID W H IC H IS MAD E U P OF
LEAD STR IPS W H IC H AR E AN GLED SLIGH TLY SO TH AT
TH EY FOC U S IN SPAC E.
• D ISTAN C E B/W TH E FOC U S AN D TH E LEAD STR IPS IS
KN OW N AS TH E FOC AL LEN GTH OF TH E GR ID