Electron beam therapy uses megavoltage electron beams to treat superficial tumors within 6 cm of the skin surface, sparing deeper tissues. The dose distribution of electron beams provides a uniform dose in the target region followed by a rapid dose fall-off. Treatment planning for electron beams requires consideration of electron energy, air gaps, tissue inhomogeneities, and adjacent fields to determine the optimal dose distribution. Electron beams can effectively treat many superficial cancers of the skin, limbs, and surgical beds.
CONTENTS
Electron arc therapy.
Introduction to electron arc therapy
Calibration of electron arc therapy
field shaping
beam energy
Treatment planning
location of the isocentre
scanning field width
collimation used in electron arc therapy.
summary
CONTENTS
Electron arc therapy.
Introduction to electron arc therapy
Calibration of electron arc therapy
field shaping
beam energy
Treatment planning
location of the isocentre
scanning field width
collimation used in electron arc therapy.
summary
Updates on Electron Beam Therapy
I) Introduction
II) Central Axis Depth dose distribution
III) Dosimetric parametrics of electron beam
IV) Clinical Considerations of Electron beam therapy
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
Updates on Electron Beam Therapy
I) Introduction
II) Central Axis Depth dose distribution
III) Dosimetric parametrics of electron beam
IV) Clinical Considerations of Electron beam therapy
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
This slide includes physical, biological properties of proton and its advantage over the photon. It also provides information from beam production to treatment planning system of proton therapy, its potential applications, cost effectiveness and demerits.
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.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
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
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
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!
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
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
2. Introduction
Electron Beam Therapy (EBT) is a kind of external beam
radiotherapy where electrons are directed to a tumour site.
Megavoltage electron beams represent an important
treatment modality in modern radiotherapy, often
providing a unique option in the treatment of superficial
Tumours
Clinically useful energies are between 6 and 20-MeV
3. Why Electrons?
Delivers a reasonably uniform dose from the
surface to a specific depth , after which dose falls
off rapidly, eventually to a near-zero value.
Using electron beams allows disease within
approximately 6 cm of the surface to be treated
effectively, sparing deeper normal tissues.
4. History of Electron Therapy
Van de Graaff Accelerators (late 1930s)
•E<3 MeV; mainly source of x-ray beams
•First used at Huntington Memorial Hospital in 1937
•Limited utilization for mycosis fungoides and other
skin cancers
Betatrons (late 1940s)
•Developed in US and Germany
•Beam line and dosimetry development
5. Linear Accelerators (1960s)
Electron beam therapy is now performed using a
medical linear accelerator.
The same device can also be used to produce
high energy photon beams
6. Clinical Utility
Electron beams have been successfully used in
numerous sites that are within 6 cm of the surface
•Cancer of skin regions, or total skin (e.g. Mycosis fungoids)
•Diseases of the limb (e.g. melanoma and lymphoma),
nodal irradiation(Neck Node Boost)
•It may also be used to boost the radiation dose to the
surgical bed after mastectomy or lumpectomy.
•For deeper regions intraoperative electron radiation
therapy can be applied.
7. Electron Interactions with matter
As electrons travel through a medium, they interact
with atoms by a variety of processes owing to Coulomb
force interactions.
The processes are..........
(a) inelastic collisions with atomic electrons
( ionization and excitation ),
(a) inelastic collisions with nuclei ( bremsstrahlung )
(b) elastic collisions with atomic electrons, and
(d) elastic collisions with nuclei
8. In inelastic collisions, some energy is lost as it is
used up in producing ionization or converted to
other forms of energy like photon energy and
excitation energy.
In elastic collision kinetic energy is not lost although
it may be redistributed among the particles
emerging from the collision.
9. Major attraction of the electron beam irradiation is the shape
of the depth dose curve.
Region of more or less uniform dose followed by a rapid
drop off of dose offers a distinct clinical advantage over the
conventional x-ray modalities.
The depth in centimetres at which electrons deliver a dose
to the 80% to 90% isodose level.
Most useful treatment depth, or therapeutic range , of
electrons is given by the depth of the 90% depth dose.
Electron beam characteristics
10. Electron beam characteristics (Depth
distribution in
water)
• Rapid rise to 100%
• Region of uniform
dose (proximal
90% to distal 90%)
• Rapid dose fall-off
• High surface dose
• Clinically useful
range 5-6 cm
depth
Because the dose decreases abruptly beyond the 90% dose level,
the treatment depth and the required electron energy must be
chosen very carefully
11. 11
Electron Beams Characteristics
Central axis depth dose curves
6
18
Modest skin sparing
↑energy ↑skin dose
Relatively
uniform dose
Rapid dose drop-off
for low energy
electron beams, but
disappears for high-
energy electron
beams
Bremsstrahlung
x-ray
contamination
The choice of beam energy is much more critical for electrons than for photons.
R80(cm) ~ E(MeV)/2.8
R90(cm) ~ E(MeV)/3.2
increases
with
energy
dmax increases with energy for low-
energy electrons, ~ 2.5cm for
high-energy electrons (12-20 MeV)
12. 12
Characteristics of Clinical Electron
Beams
Central axis depth dose curves – buildup region
Lower energy electrons
scatter more and through
larger angles, causing more
rapid buildup, thus, the
difference between the
surface dose and maximum
dose is larger.
Higher energy electrons
scatter less and through
smaller angles, causing less
rapid buildup (in the extreme
case, if there is no scatter,
there will be no buildup).
13. Absorbed dose (also known as total ionizing dose, TID) is a
measure of the energy deposited in a medium by ionizing
radiation per unit mass, which may be measured as joules per
kilogram when it is represented by the equivalent SI
unit, gray (Gy).
The absorbed dose from a given level of incident radiation
depends on the absorbing medium. For instance, a soft X-ray
beam may deposit four times more dose in bone than in air, or
none at all in a vacuum.
Absorbed dose
14. 14
Determination of Absorbed Dose
Absorbed dose can be measured with:
ionozation chamber
calorimetry
Fricke dosimetry
Relative dose can be measured with:
Film: energy independence for electron beam, TLD
Diode : often used for electron beam measurement.
16. Beams of ionising radiation have characteristic
processes of energy deposition, hence the
Expected dose distribution can be estimated.
In order to represent volumetric and planar
variations in absorbed dose, distributions are
depicted by means of ISODOSE CURVES .
17. PDD(Percentage depth dose)
The quantity percentage depth
dose may be defined as the
quotient,
expressed as a percentage, of
the absorbed dose at any
depth 'd‘ to the absorbed dose
at a fixed reference depth 'd0'
,along the central axis of the
beam.
18. ISODOSE CURVES
DEFINITION:
Isodose curves are the lines joining the points of
equal Percentage Depth Dose (PDD). The curves are
usually drawn at regular intervals of absorbed dose and
expressed as a percentage of the dose at a reference
point.
ISODOSE CHARTS : It consists of a family of isodose curves.
The depth dose values of the curves are
normalized:
1) At the point of maximum dose on the central axis (Dmax)
2) At a fixed distance along the central axis in the irradiated
medium (SAD).
19. Measurement of isodose curves
1. Ion Chambers
2. Solid state detectors
3. Radiographic Films
4. Computer driven devices
Ion chamber is the most reliable method,
because of its relatively flat energy response
and precision
20. Most useful treatment depth , therapeutic range of
electrons is given by the depth of 90% of the isodose
curves……….
The PDD increases as the energy
increases.
However unlike photon beams ,
the percent of surface
dose for electron beam increases
with energy
21. 21
Electron Beams
For low energy electron
beams, isodose curves
bulging out for all dose
levels
Isodose curves
23. The term penumbra generally defines the region at the
edge of the radiation beam over which the dose rate
changes rapidly as a function of distance from the
beam central axis.
Penumbra
The physical penumbra of
an electron beam may be
defined as the distance
between two specified
isodose
curves at a specified
depth in phantom.
25. As with photon beam treatments, the first step in the
initiation of electron therapy is to determine accurately the
target to be treated .
All available diagnostic, operative, and medical
information should be consulted to determine the extent
and the final planning target volume (PTV) with
appropriate margins to be treated before simulation and
placement of the electron fields is initiated.
Target definition
26. Most electron beam treatments are planned for a single field
technique.
For a relatively flat and homogeneous block of tissue, dose
distribution can be found using appropriate isodose chart.
Treatment planning is a exception rather
than a rule.
Surface areas are seldon flat, and in many cases
inhomogeneous such a bone,lung and air cavities, which
causes dosimetric calculations a little bid complex.
27. Treatment planning...........
A.Choice of Energy and field size
B.Correction for air gap and beam
obliquity
C.Tissue inhomogenicites
D.Use of bolus and absorbers
E.Problems of adjacent fields
28. Treatment planning...........
Choice of Energy and field size
The energy beam is directed in general by
The depth of the target volume.
Minimum target dose required
Cinically acceptable dose to a critical organ
The electron energy for treatment should be selected such
that the depth of the 90% isodose line covers the distal or
deepest portion of the region to be treated in addition to an
approximate 5-mm additional depth beyond the treatment
region
29. Correction for air gap and beam obliquity
Treatment planning...........
In electron beam therapy, there is a frequent problem
of the treatment of the cone end not being parallel to the
skin surface.
Uneven air gaps as a result of curved patient surfaces
are often present in clinical use of electron beam
therapy.
Inverse square law corrections can be made to the
dose distribution to account for the sloping surface
30. The inverse square correction alone does not
account for changes in side scatter as a result of
beam obliquity which:
Increases side scatter at the depth of
maximum dose, Zmax
Shifts zmax toward the surface
Decreases the therapeutic depths R90 and R80.
31. Tissue inhomogenicity
Treatment planning...........
Electron beam dose distribution can be significantly altered
in presence of tissue heterogeneity such as bone, lung
and air cavities.
It is difficult to determine dose distribution in presence of
such conditions.
The simplest correction for a tissue inhomogeneity
involves the scaling of the in homogeneity thickness by
its electron density relative to that of water and the
determination of the coefficient of equivalent thickness
(CET)
32. Use of bolus and absorbers
Treatment planning...........
Bolus is often used in electron beam therapy
Flatten out an irregular surface
Reduce the penetration of electron in parts of the field
Increase in the surface dose
To shorten the range of a given electron beam in the
patient
Bolus made of tissue equivalent material, such as
wax
33. The use of computed tomography (CT) for treatment
planning enables accurate determination of tumour
shape and patient contour.
34. Occasionally, the need arises to abut electron fields.
When abutting two electron fields, it is important to
take into consideration the dosimetric characteristics
of electron beams at depth in the patient.
The large penumbra and bulging isodose lines
produce hot spots and cold spots inside the target
volume
CLINICAL CONSIDERATIONS
In general, it is best to avoid using adjacent electron
fields
35. Electron arc therapy
Electron arc therapy is a special radiotherapeutic
treatment technique in which a rotational electron beam
is used to treat superficial tumour volumes that follow
curved surfaces.
While its usefulness in treatment of certain large
superficial tumours is well recognized, the technique is
not widely used because it is relatively complicated,and
its physical characteristics are poorly
understood
36. Two approaches to electron arc therapy have been
developed:
• Electron pseudo-arc based on a series of overlapping
stationary electron fields.
• Continuous electron arc using a continuous rotating
electron beam
The calculation of dose distributions in electron arc
therapy is a complicated procedure that generally cannot
be performed reliably with the algorithms used for
standard electron beam treatment planning
37. Total Skin Irradiation
2-9 MeV electron beams are useful for treating
superficial lesions covering a large areas of the body
(e.g. mycosis fungoides)
38. The clinically useful energy range of electrons is 6 to 20 MeV, usefull
for treating superficial skin tumours of less than 6 cm
Energy of electron beam is specified by the most probable energy at
the surface.
Depth dose distribution can be determined by ion chamber, diodes and
film
Field shaping can be done with lead or cerrobend cutouts.
Electron arc threapy is feasible for tumors along curved surface also
with proper shielding.
Conclusion...