Dosimetric Evaluation of High Energy Electron Beams Applied in RadiotherapyAYMAN G. STOHY
Electron-beam therapy: is used to treat superficial tumors at a standard 100 cm source-to-surface distance (SSD). Characteristics of electron beams from an Elekta PreciseTM linear accelerator are presented at a nominal SSD of 100 cm. However, certain clinical situations require the use of an extended SSD. The effects of extended source-to-surface distance (SSD) on the electron beam dose profiles were evaluated for various electron beam energies 6, 8, 10,12 and 15 MeV and the accuracy of various output correction methods was analyzed on an Elekta PreciseTM linear accelerator using a radiation field analyzer (RFA). Effective SSDs was evaluated for field sizes ranging from 6×6, 10×10, 14×14 and 20×20 cm2 for various energies.
Aim of the work
1.Investigate the physical properties of electron beams
at different beam energies.
2.Evaluate the accuracy of dose calculated by
Treatment Planning System (TPS) and measured for
different field configurations.
Dosimetric Evaluation of High Energy Electron Beams Applied in RadiotherapyAYMAN G. STOHY
Electron-beam therapy: is used to treat superficial tumors at a standard 100 cm source-to-surface distance (SSD). Characteristics of electron beams from an Elekta PreciseTM linear accelerator are presented at a nominal SSD of 100 cm. However, certain clinical situations require the use of an extended SSD. The effects of extended source-to-surface distance (SSD) on the electron beam dose profiles were evaluated for various electron beam energies 6, 8, 10,12 and 15 MeV and the accuracy of various output correction methods was analyzed on an Elekta PreciseTM linear accelerator using a radiation field analyzer (RFA). Effective SSDs was evaluated for field sizes ranging from 6×6, 10×10, 14×14 and 20×20 cm2 for various energies.
Aim of the work
1.Investigate the physical properties of electron beams
at different beam energies.
2.Evaluate the accuracy of dose calculated by
Treatment Planning System (TPS) and measured for
different field configurations.
Measurement Procedures for Design and Enforcement of Harm Claim ThresholdsPierre de Vries
Presentation at DySPAN 2017, March 2017
Paper forthcoming on IEEE Xplore
Paper authors:
Janne Riihijärvi, Petri Mähönen (RWTH Aachen University, Germany)
J. Pierre de Vries (Silicon Flatirons Centre, University of Colorado, USA)
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
5. Why do you need to know this?
• Basic fundamental knowledge in your field
• May be called upon to perform calculations
• Need to know how the parameters effect
dose calculations
• You need to be able to detect errors
• Career opportunities
6. Why do you need to know this?
• Recent news reports highlight
errors in radiation oncology
• Over reliance on technology
• Therapists job has become
increasingly segmented
• An overall grasp of the basics is
essential
7. Outline
• Basic Principles
• Non-Isocentric (or SSD) Calculations
• SSD example
• Isocentric (or SAD) Calculations
• SAD example
8. Basic Principles: Dose and Prescription
• Radiation Dose (cGy) • The Radiation Therapy Rx
• 4500cGy @ 180cGy x 25
9. Basic Principles: Linear Accelerator / Cobalt Unit
• Radiation Source
• Rotating Gantry
• Source to Axis Distance (SAD)
• Field Defining Collimators
• MLCs or Blocks
• Treatment accessories (e.g. wedges)
10. Basic Principles: Machine Calibration
Cobalt Unit (cGy/min) / Linear Accelerator (cGy/MU)
Source
Point of Dmax
Reference Field Size 100 SSD
Surface
13. Basic Principles: Equivalent Square
• Collimators always define a square or rectangular field size
• Calculation data is tabulated according to square field size
• The equivalent square concept allows one to determine a square
field size that is “equivalent” to the rectangular field as relates to
dosimetry
• Sterling’s Formula
– S = 4xAREA/PERIMETER
• Tables based upon measurement
• The equivalent square is use to look up dosimetric parameters
related to the primary collimator settings
L
W
S
S
14. Basic Principles: Effective Square
• Most times a rectangular field from the primary collimators is not appropriate
• Field defining blocks (or muli-leaf collimators) further modify the field
• The effective square concept allows one to determine a square field size that is
“effectively” equal to the blocked field as relates to dosimetry
• Remember to incorporate a tray factor when using a block
• The equivalent square is use to look up dosimetric parameters related to the field
size on the patient’s surface
12% Blocking
15. Non-Isocentric or SSD Setup Isocentric or SAD Setup
Basic Principles: Non-Isocentric and Isocentric Calculations
Patient surface is at the axis of rotation Calculation point is at the axis of rotation
SSD = SAD = 100 cm
d = 5 cm
d = 5 cm
SSD = 95 cm
16. Basic Principles: SSD Setup - Percent Depth Dose (PDD)
• Radiation dose decreases with depth
• For high energy x-rays (Megavoltage),
dose initially builds up to a maximum
and then decreases with depth
• The PDD is the primary parameter used
to calculate dose for SSD setups
•
17. Source
Dmax
Field Size
Source
Depth = d
Field Size
SAD = 100 cm
SAD = 100 cm
Tissue Maximum Ratio (TMR) = Ratio of dose at depth d to the dose at dmax for a given field size
TMR is the parameter used to calculate dose for SAD setups
Basic Principles: SAD Setup – Tissue Maximum Ratio (TMR)
18. Basic Principles: Sc
• Collimator scatter factor
• Quantifies the relationship between
the field size setting and the dose
resulting from scattering from the
machine collimators
• NOTE: Sc is a function of the field
size defined in the treatment head,
not the final field size that reaches
the patient
Scatter off the collimators
19. Basic Principles: Sp
• Phantom scatter factor
• Quantifies the relationship between
the field size on the patients surface
and the dose resulting from scatter
within the patient
• NOTE: Sp is a function of the field
size as defined on the patient, not
the field size as defined in the
treatment head
Field size on the patient surface
20. Basic Principles Review: Radiation Prescription
• Prescribed total dose (cGy)
• Prescribed dose per fraction (cGy)
• Energy
• Prescription point
• Field Weighting (for multiple fields)
