Computed tomography (CT) uses x-rays and computer processing to create cross-sectional images of the body. CT imaging involves data acquisition where x-rays are passed through the body and detected, image reconstruction where computer processing converts the data into images, and image display. Key factors in image quality include spatial and contrast resolution. CT has advanced from single detector to multi-detector systems, allowing faster scanning over larger areas.
Basic physics of multidetector computed tomography ( CT Scan) - how ct scan works, different generations of ct, how image is generated and displayed and image artifacts related to CT Scan.
Basic physics of multidetector computed tomography ( CT Scan) - how ct scan works, different generations of ct, how image is generated and displayed and image artifacts related to CT Scan.
Quality Assurance Programme in Computed TomographyRamzee Small
Introduction to Computed Tomography
Basic description of the components of a CT System
Introduction to Quality Assurance
Quality Assurance and Quality Control Tests in Computed Tomography base on frequency
Objective of QA/QC Test
detailed presentation of CT scan history, equipment fro first year radiology residents. Helps to know the evolution of generations of CT scan, artefacts and their reduction.
Quality Assurance Programme in Computed TomographyRamzee Small
Introduction to Computed Tomography
Basic description of the components of a CT System
Introduction to Quality Assurance
Quality Assurance and Quality Control Tests in Computed Tomography base on frequency
Objective of QA/QC Test
detailed presentation of CT scan history, equipment fro first year radiology residents. Helps to know the evolution of generations of CT scan, artefacts and their reduction.
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it includes generations and advancement in CT. In generations fifth generation CT is described in detail.
UFC detector, stellar detectors and gemstone detector is also described
straton x-ray tube, MRC, LIMAX and aquillion one xray tube
different techniques used in CT
dual energy CT is also described
CHAPTER 1 SEMESTER V PREVENTIVE-PEDIATRICS.pdfSachin Sharma
This content provides an overview of preventive pediatrics. It defines preventive pediatrics as preventing disease and promoting children's physical, mental, and social well-being to achieve positive health. It discusses antenatal, postnatal, and social preventive pediatrics. It also covers various child health programs like immunization, breastfeeding, ICDS, and the roles of organizations like WHO, UNICEF, and nurses in preventive pediatrics.
Antibiotic Stewardship by Anushri Srivastava.pptxAnushriSrivastav
Stewardship is the act of taking good care of something.
Antimicrobial stewardship is a coordinated program that promotes the appropriate use of antimicrobials (including antibiotics), improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multidrug-resistant organisms.
WHO launched the Global Antimicrobial Resistance and Use Surveillance System (GLASS) in 2015 to fill knowledge gaps and inform strategies at all levels.
ACCORDING TO apic.org,
Antimicrobial stewardship is a coordinated program that promotes the appropriate use of antimicrobials (including antibiotics), improves patient outcomes, reduces microbial resistance, and decreases the spread of infections caused by multidrug-resistant organisms.
ACCORDING TO pewtrusts.org,
Antibiotic stewardship refers to efforts in doctors’ offices, hospitals, long term care facilities, and other health care settings to ensure that antibiotics are used only when necessary and appropriate
According to WHO,
Antimicrobial stewardship is a systematic approach to educate and support health care professionals to follow evidence-based guidelines for prescribing and administering antimicrobials
In 1996, John McGowan and Dale Gerding first applied the term antimicrobial stewardship, where they suggested a causal association between antimicrobial agent use and resistance. They also focused on the urgency of large-scale controlled trials of antimicrobial-use regulation employing sophisticated epidemiologic methods, molecular typing, and precise resistance mechanism analysis.
Antimicrobial Stewardship(AMS) refers to the optimal selection, dosing, and duration of antimicrobial treatment resulting in the best clinical outcome with minimal side effects to the patients and minimal impact on subsequent resistance.
According to the 2019 report, in the US, more than 2.8 million antibiotic-resistant infections occur each year, and more than 35000 people die. In addition to this, it also mentioned that 223,900 cases of Clostridoides difficile occurred in 2017, of which 12800 people died. The report did not include viruses or parasites
VISION
Being proactive
Supporting optimal animal and human health
Exploring ways to reduce overall use of antimicrobials
Using the drugs that prevent and treat disease by killing microscopic organisms in a responsible way
GOAL
to prevent the generation and spread of antimicrobial resistance (AMR). Doing so will preserve the effectiveness of these drugs in animals and humans for years to come.
being to preserve human and animal health and the effectiveness of antimicrobial medications.
to implement a multidisciplinary approach in assembling a stewardship team to include an infectious disease physician, a clinical pharmacist with infectious diseases training, infection preventionist, and a close collaboration with the staff in the clinical microbiology laboratory
to prevent antimicrobial overuse, misuse and abuse.
to minimize the developme
CHAPTER 1 SEMESTER V - ROLE OF PEADIATRIC NURSE.pdfSachin Sharma
Pediatric nurses play a vital role in the health and well-being of children. Their responsibilities are wide-ranging, and their objectives can be categorized into several key areas:
1. Direct Patient Care:
Objective: Provide comprehensive and compassionate care to infants, children, and adolescents in various healthcare settings (hospitals, clinics, etc.).
This includes tasks like:
Monitoring vital signs and physical condition.
Administering medications and treatments.
Performing procedures as directed by doctors.
Assisting with daily living activities (bathing, feeding).
Providing emotional support and pain management.
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Objective: Promote healthy behaviors and educate children, families, and communities about preventive healthcare.
This includes tasks like:
Administering vaccinations.
Providing education on nutrition, hygiene, and development.
Offering breastfeeding and childbirth support.
Counseling families on safety and injury prevention.
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Objective: Collaborate effectively with doctors, social workers, therapists, and other healthcare professionals to ensure coordinated care for children.
Objective: Advocate for the rights and best interests of their patients, especially when children cannot speak for themselves.
This includes tasks like:
Communicating effectively with healthcare teams.
Identifying and addressing potential risks to child welfare.
Educating families about their child's condition and treatment options.
4. Professional Development and Research:
Objective: Stay up-to-date on the latest advancements in pediatric healthcare through continuing education and research.
Objective: Contribute to improving the quality of care for children by participating in research initiatives.
This includes tasks like:
Attending workshops and conferences on pediatric nursing.
Participating in clinical trials related to child health.
Implementing evidence-based practices into their daily routines.
By fulfilling these objectives, pediatric nurses play a crucial role in ensuring the optimal health and well-being of children throughout all stages of their development.
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QA Paediatric dentistry department, Hospital Melaka 2020Azreen Aj
QA study - To improve the 6th monthly recall rate post-comprehensive dental treatment under general anaesthesia in paediatric dentistry department, Hospital Melaka
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How many patients does case series should have In comparison to case reports.pdfpubrica101
Pubrica’s team of researchers and writers create scientific and medical research articles, which may be important resources for authors and practitioners. Pubrica medical writers assist you in creating and revising the introduction by alerting the reader to gaps in the chosen study subject. Our professionals understand the order in which the hypothesis topic is followed by the broad subject, the issue, and the backdrop.
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Telehealth Psychology Building Trust with Clients.pptxThe Harvest Clinic
Telehealth psychology is a digital approach that offers psychological services and mental health care to clients remotely, using technologies like video conferencing, phone calls, text messaging, and mobile apps for communication.
2. TOMOGRAPHY
• Also known as Computerized Axial Tomography (CAT Scan)
• Comes from the Greek word Tomos- to cut
• Preliminary image- Topogram (Siemens), Scanogram (Toshiba), Scout (G.E)
4. CT IMAGE
QUALITY:CRITERIA
Spatial Resolution- ability of a system to define small
objects distinctly
Low Contrast Resolution-ability of a system to
differentiate, on the image, objects with similar densities
Temporal Resolution- speed that the data can be acquired
5. Type to enter a caption.
X axis- width
Y axis- height
Z axis- thickness of the slices
Pixel-two dimensional squares
Picture element(X & Y)
Voxel- three dimensional cube
Voxel element (X, Y & Z)
Matrix-grid formed by rows and columns
512 x 512- common matrix size in CT
Total of 262,144 pixels
6. Type to enter a caption.
Photons- bundle of energy in
an xray beam
Attenuation- the degree to which
an xray beam is reduced by an
object
The quantities of xray photons that pass
through the body determines the shades of
gray on the image.
7. The number of photons that interact
increases with density, thickness &
atomic number
Low attenuation- xray photons that pass through
objects unimpeded
-black area on image
High attenuation- object that has the ability to
absorb much of xray beam
8. Density- defined as the mass of the substance
per unit volume.
To differentiate adjacent objects on a CT image,
there must be density difference between two
objects.
Measurements are expressed in Hounsfield units (HU)
9. The amount of xray beam that is scattered or
absorbed per unit of the absorber is expressed
by Linear attenuation coefficient
Type to enter a caption.
10. High density contrast agents/ Positive
agents- barium sulphate, iodine (Scanlux,
Omnipaque, Visipaque)
Low density CA/ Negative agents- water
11. Sir Godfrey N. Hounsfield, DSc
Father of computed tomography
Won a nobel prize in 1979 with
Allan M. Cormack
Hounsfield units-aka CT numbers/ density values.
Quantify the degree that a structure attenuates
an xray beam
Distilled water- 0
Bone- +1000
Air- -1000
Type to enter a
12. All xray beam sources for CT and radiography
produce xray energy that is polychromatic
Artifacts are object seen
on the image but not present
in the object scanned. It
degrades image quality
.
13. Beam hardening artifact/ Cupping
Artifact- most common when xray
Beam first penetrates a dense
Structure. Appears as dark streaks
14. Volume Averaging- The process in CT by which different
tissue attenuation values are averaged to produce one
less accurate pixel
Partial volume artifact occurs when tissues of widely
different absorption are averaged together in a slice.
Type to enter a caption.
Can be minimised
by creating thinner
slices of the same area
17. STEP AND SHOOT SCANNING
Advantage:
Highest image quality, superior than spiral/helical methods
Disadvantage:
Longer scan time
Misregistration-esp when there is motion
18. HELICAL SCANNING/VOLUMETRIC SCANNING
Continually rotating xray tube, constant xray output, uninterrupted
Table movement
Uses slips rings for continuous rotation of xray tube
Type to enter a caption.
19. Pitch-travel distance of CT
scan table per 360 rotation of
the xray tube divided by xray
beam collimation width
Pitch of 1 or 1.5 is common
Higher pitch-Faster table
movement-decrease scan time-
increase image noise
Type to enter a caption.
23. • SLIP RINGS
-Brush like apparatus to provide continuous, electrical
Power and electronic communication across a rotating
surface.
-used in helical scanners
• GENERATOR
-High frequency
-Power capacity in KW
-120-140 kV
Type to enter a caption.
24. • XRAY TUBE
Tungsten anode
Focal Spot size 0.5 and 1.0
• FILTRATION
Compensating filters-shape the xray beam
Ex: Bow tie filter
Reduce the radiation dose by filtering the long wav
• COLLIMATION
-restrict the xray beam reducing scatter radiation
-controls slice thickness
26. Types of collimator
Source collimator/Pre-patient collimation
Located near the xray source
Affects patient dose
Determines how the dose is distributed across the slice
Thickness
Resembles small shutters, dependent on operators
Selection of slice thickness
Predetector collimator/Postpatient collimation
Ensure the beam is the proper width
Prevent scatter radiation from reaching the detector
30. • DETECTORS
Optimal Characteristics:
1. High detector efficiency- ability to capture transmitted photo
2. low/no afteglow- brief persistent flash of scintillation
3. High scatter suppresion
4. High stability
31. Factors of Detector Efficiency
1. Stopping power of the detector material
2. Scintillator efficient (solid state)
3. Charge collection efficiency (xenon detectors)
4. Geometric efficiency- amount of space occupied by
the detector collimator plates relative to the surface
area of the detector
5. Scatter rejection
Type to enter a caption.
32. Capture Efficiency- ability which detector obtains
photons that have passed through the patient
Absorption efficiency- number of photons
absorbed by the detector and is dependent on the
physical properties of the detector face (thickness,
material)
Response time- time required for the signal from
the detector to return to zero after stimulation by
xray radiation, so that it is ready to detect another
xray event.
Dynamic range- ratio of maximum signal
measured to the minimum signal the detectors can
measure.
33. TYPES OF DETECTORS
XENON GAS DETECTORS
(GAS FILLED ION CHAMBER)
SOLID STATE CRYSTAL
DETECTOR
Type to enter a
34. XENON GAS DETECTORS
Type to enter a
caption.
Less expensive
Highly stable
Consist of three tungsten plates
Has aluminum casing
(kept under pressure)
Photon->ionises xenon->ions are
amplified->collected charge
produces current->raw data
Capture about 50% photons
in the beam
35. SOLID STATE CRYSTAL DETECTOR
A.k.a. Scintillation Detectors
Use crystal that fluoresces when struck by xray
photon.
Cadmium tungstate, bismuth germanate,
Cesium Iodide, Ceramic rare earth compounds
(Gd & Yttrium)
Photodiode- converts light energy
to electrical energy
About 80%
capture efficient
37. SCANNER GENERATION
Produced by EMI medical division
Scan time-4-5mins, Matrix 80x80, 180times repeat linear motion
In this unit head was enclosed in a water bath
Rotate-Translate,Pencil Beam
38. Detector array(30) was incorporated
Scan time: 10-90 sec
Rotate-Translate, Narrow Fan beam
39. Fixed relationship between Xray source and detectors(arc)
A.k.a Rotate-rotate scanner
Disadvantage: Ring Artifacts, Scan time 2-10 sec
Rotate-rotate wide fan beam
41. EBCT/ ELECTRON BEAM IMAGING/ULTRAFAST CT
Produced by Imatron, uses a large electron gun as an xray source
Neither the xray beam or detectors move
Scan can be acquired in shorter time (acquisition time-100msec)
For cardiac and paediatric imaging
Type to enter a caption.
46. • DAS/ DATA ACQUISITION SYSTEM
Measures the number of
photons that strikes the
detector, converts the
information to a digital
signal and sends the
signal to the computer
49. IMAGE RECONSTRUCTION
Algorithm-finite set of unambiguous steps performed in a
prescribed sequence to solve a problem.
Fourier transform- developed by Baron Jean Baptiste Joseph
Fourier (17th century)
-method to study waves of many different sorts and solve kinds
of linear differential equations
Interpolation- mathematical method of estimating a value of an
unknown function using the known value on either side of the
function. (creating a missing data)
TERMINOLOGY
50. DATA TYPES
Raw Data
Refer to the fatal sitting in the computer waiting to be made into
an image. The process of using raw data to create an image is
called Image Reconstruction
Prospective reconstruction- automatically produced during
scanning
Retrospective reconstruction- uses raw data to generate
new image after scanning
51. Image Data
Are those which result once the computer has processed
the raw data. One hounsfield unit value is assigned to
each pixel
Type to enter a caption.
56. FILTERED BACK PROJECTION
Filtering is applied to the scan data BEFORE back
projection occurs.
Convolution-applying a filter function to an attenuation
profile
Filtered back projection algorithms use Fourier theory to
reduce statistical noise
60. Scan Field of View (SFOV)
Calibration field of view.
Determines the area from which
the raw data are acquired
Small SFOV- 25 cm (head)
Medium-35 cm
Large 42-50 cm
Type to enter a
caption.
61. Display Field of View (DFOV)
Zoom/ Target
Determines how much of the
collected raw data is used to
create an image
Cannot be larger than SFOV
Type to enter a
63. IMAGE DISPLAY
WINDOW WIDTH
s the quantity of hounsfield units represented as shades of grey on a sp
Type to enter a
caption.
WINDOW LEVEL
Selects which hounsfield values are displayed as shades of gray.
Selects the centre CT value of the window width
64. Type to enter a
caption.
Wide window width (500-
2000 HU)- best for imaging
tissue types that cary
greatly
Narrow window width (50-
500HU)- tissues with similar
densities