Step-by-Step Stereotactic Radiotherapy Planning of Vestibular Schwannoma: A Guide to Radiation Oncologists—the ROSE Case (Radiation Oncology from Simulation to Execution)
This document provides a step-by-step guide to stereotactic radiotherapy planning for vestibular schwannoma. It describes the case of a 40-year-old male patient presenting with symptoms of tinnitus, dizziness, and facial twitching. Imaging including CT and MRI confirmed a right-sided vestibular schwannoma. The tumor was graded and treatment options were discussed. The patient was planned for fractionated stereotactic radiotherapy to a dose of 25Gy in 5 fractions based on guidelines. The planning process is then described in detail, including CT simulation, MRI protocol, contouring of targets and organs at risk, plan evaluation criteria, and subsequent treatment.
Hypofractionation in early breast cancer is no more a research scholars topic. Multiple studies with robust data have proven its utility. It may hold an important role in many countries with constrained resources. This is a short presentation incorporating important completed and ongoing trials. Feel free to use this.
Hypofractionation in early breast cancer is no more a research scholars topic. Multiple studies with robust data have proven its utility. It may hold an important role in many countries with constrained resources. This is a short presentation incorporating important completed and ongoing trials. Feel free to use this.
Particle beam – proton,neutron & heavy ion therapyAswathi c p
particle therapy is advanced external beam therapy used to treat cancer , which uses beams of protons or other charged particles such as helium, carbon or other ions instead of photons. charged particles have different depth-dose distributions compared to photons. They deposit most of their energy in the last final millimeters of their trajectory (when their speed slows). This results in a sharp and localized peak of dose, known as the Bragg peak.
Particle beam – proton,neutron & heavy ion therapyAswathi c p
particle therapy is advanced external beam therapy used to treat cancer , which uses beams of protons or other charged particles such as helium, carbon or other ions instead of photons. charged particles have different depth-dose distributions compared to photons. They deposit most of their energy in the last final millimeters of their trajectory (when their speed slows). This results in a sharp and localized peak of dose, known as the Bragg peak.
Similar to Step-by-Step Stereotactic Radiotherapy Planning of Vestibular Schwannoma: A Guide to Radiation Oncologists—the ROSE Case (Radiation Oncology from Simulation to Execution)
The students at Wilmington High School have Career Day to generate interest in all the many careers they may choose to pursue. Here is the Power Point presentation I developed to help explain the job of being a Radiation Therapist.
Study of current pattern of Cervical Spondylotic Myelopathy and to evaluate t...iosrjce
IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Primary Hemangiopericytoma in Parietal Bone: Literature Review and Case Reportkomalicarol
Hemangiopericytoma (HPC) is a tumor from
pericytes surrounding capillary walls. Most HPCs grow slowly,
but others display aggressive growth. Treatment for HPC is total
resection or resection plus adjuvant radiation.
Study on Physicians Request for Computed Tomography Examinations for Patients...IRJESJOURNAL
Background and objectives: There is a lot controversy about the use of Computed tomography (CT) for patients with minor head injury. We aimed to determine the practice of guiding rules for the safety of radiation and increasing awareness of physicians about risks of ionizing radiation and find out the reasons of emergency doctors for sending head injury patients to CT scan exams. Materials and Methods: A descriptive questionnaire in the Emergency Department (ED) based study was performed to assess physicians' knowledge of radiation doses received from radiological treatments and knowledge about Clinic Decision Support rules (CDS). The questionnaire consisted of 26 questions distributed to physicians working in the emergency department in six hospitals in East Java. Finally, the data collected have been analyzed by some tests using SPSS version 15 and Smart PLS. Results: In this study 44 participants had taken part. The percentage of general knowledge and awareness that shows the response of people who work in the emergency departments was total 44 respondents, by percent 6.8% of the respondents had passably knowledge, awareness and 84.1% they were having a good knowledge and awareness and 9.1% the respondents had very good knowledge and awareness. That means almost of respondents have good knowledge and awareness. To find out if an indicator is forming a construct (latent variables) testing the convergent validity of the measurement model with a reflexive indicator assessed based on the correlation between the item score to construct scores were calculated with the help of software Smart PLS. Size reflexive considered valid if the individual has a correlation (loading) to construct (latent variables) to be measured ≥ 0.5 or the value of t-statistics should ≥1.96 (test two tailed) at a significance level of α = 0.05. If one of the indicators has a leading value <0.5,><1.96, then the indicator should be discarded (dropped) because it indicates that the indicators are not good enough to measure the construct in right. The positive influence between general knowledge and awareness against to knowledge about radiation doses can be interpreted that the better general knowledge and awareness, then it will be followed by an increase in their knowledge about radiation doses. And vice versa, the worse general knowledge and awareness, then this will decrease their knowledge about radiation doses too. Conclusion: The present study has illustrated that the level of awareness and knowledge physicians who deal with ionizing radiation in CT scan units are adequate overall. There is a good influence between the diligence in applying the principles of guidance and rules stipulated by the nuclear energy in Indonesia by physicians to adjust the use of CT in the emergency department, the majority of participants who have a good awareness & knowledge, there are some of them do not have enough knowledge.
Primary Small Cell Neuroendocrine Carcinoma of the Petrous Apex: A Report of ...IJBNT Journal
Small cell neuroendocrine carcinomas (SCNEC) are extremely rare in the head and neck region, known to be highly aggressive with poor prognosis. We report the second case in the literature of a poorly differentiated SCNEC involving the petrous apex of the temporal bone, and we present its management.
This one is my Physics Investigatory Project done on the topic 'Physics Principle In Medicine'. You and I both of us know, without physics advancement in biology especially in the medical field is impossible. So, in this project we are gonna investigate through the various principles of physics which are used in the medical field ( like X ray machines, CT scanners, MRI and other advancements like SPECTS scan).
Both for class 11th & 12th.
Especially for class 12th.
Thank You... Hope you find it useful...
— Treatment of nasopharyngeal carcinoma is done by advanced radiotherapy techniques like VMAT (Volumetric Modulated Arc Therapy) where dose to critical organs around tumour is of concern. Present study aimed to describe radiation dose to critical organs in nasopharyngeal cancer patients using VMAT technique. Study was conducted on 10 carcinoma nasopharynx patients treated by VMAT technique at a super-specialty cancer institute in Rajasthan. The structures were contoured using RTOG (Radiation Therapy Oncology Group) guidelines and dose prescription to PTV (Planning Target Volume) was such that 95% iso-dose covered 100% of PTV. Constraints to the OARs (Organs at risk) were as per QUANTEC (Quantitative Analysis of Normal Tissue Effects in the Clinic). VMAT planning was done by double arc using Eclipse (v 10.0.42) treatment planning system. Mean dose to brain stem, spinal cord and optic chiasma were 51.79 Gy, 45.92 Gy and 18.8 Gy respectively. Mean dose to left and right temporal lobes was 22.7Gy and 24.3Gy. Dose to right and left eye were 20.6 Gy and 19.2 Gy while dose to right and left lenses were 5.9Gy and 5.8 Gy respectively. Dose to brain stem, spinal cord, optic chiasma, eyes, lens and temporal lobes were below the dose constraints. VMAT is an effective way to deliver maximum radiation to tumour tissue while providing better sparing of normal tissue and less doses to OARs in carcinoma nasopharynx.
Drs. Potter and Richardson's CMC Pediatric X-Ray Mastery August CasesSean M. Fox
Drs. Potter and Richardson are interested in education and Pediatric Emergency Medicine. Follow along with the EMGuideWire.com team and Dr. Michael Gibbs as they post these educational, self-guided radiology slides on Pediatric Emergency Medicine Radiology Topics including: Tetralogy of Fallot, Pneumonia, Bronchiolitis, Esophageal Foreign Body, Pneumothorax, ECMO
Similar to Step-by-Step Stereotactic Radiotherapy Planning of Vestibular Schwannoma: A Guide to Radiation Oncologists—the ROSE Case (Radiation Oncology from Simulation to Execution) (20)
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
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We specializes in exporting high quality Research chemical, medical intermediate, Pharmaceutical chemicals and so on. Products are exported to USA, Canada, France, Korea, Japan,Russia, Southeast Asia and other countries.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
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.
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.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
- 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
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
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.
Title: Sense of Smell
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 primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Step-by-Step Stereotactic Radiotherapy Planning of Vestibular Schwannoma: A Guide to Radiation Oncologists—the ROSE Case (Radiation Oncology from Simulation to Execution)
2. Patro, et al.: SRS ROSE case Vestibular Schwannoma
Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021 69
A 40-year-old male presented with the chief complaints
of tinnitus for six months, a slight decrease in hearing,
dizziness, and facial fasciculation and twitching for three
months. There was no associated facial numbness.
A patient with symptoms of tinnitus, dizziness, facial
fasciculation, and twitching must be evaluated using
the Tinnitus Handicap Inventory, Dizziness Handicap
Inventory and House-Brackmann Scale for facial nerve
functioning, respectively.[2]
On evaluation of the present
case, the patient had grade II tinnitus using the Tinnitus
Handicap Inventory and grade II dizziness using the
Dizziness Handicap Inventory, as is depicted in Table
1. On speech audiometry, the patient had a speech
discrimination score (SDS) of 90% in the right ear and 95%
in the left ear. On Pure-Tone Audiometry examination, the
pure tone average was 35 dB for the right ear and 22 dB
for the left ear. With the above pure tone average (dB) and
the SDS, the patient was found to have grade II hearing
loss of the right ear, that is, the hearing of the right ear
was serviceable as per the Gardner-Robertson grade.
The facial nerve functioning was evaluated by House-
Brackmann Scale. The patient had a normal resting
tone with slight weakness in appearance, that is, grade II
whereas forehead, eyes, and mouth were normal, that is,
grade I as is shown in Table 1.
Imaging
On imaging by computed tomography (CT) scan of the
brain, there was a widening of the right acoustic porous
with an ice-cream on cone appearance. The lesion was
minimally enhanced, touching the brainstem without any
bony involvement [Figure 1A]. The FSPGR sequence of
magnetic resonance imaging (MRI) of the brain revealed
a fairly well-defined lobulated moderately enhanced
extra-axial lesion with altered signal intensity in the right
cerebellopontine angle cistern measuring 21 mm x 16 mm
Table 1: Tinnitus, dizziness grading system Gardner–Robertson grade, and House–Brackmann scale for vestibular schwannoma
Tinnitus handicap inventory
Grade Descriptions The present case has grade II tinnitus
I No tinnitus
II Intermittent or mild tinnitus, can only be heard when the ambient noise is low
III Persistent or moderate tinnitus, can be heard everyday
IV Persistent and severe tinnitus, interfere with work and sleep
Dizziness handicap inventory
Grade Descriptions The present case has grade II dizziness
I No dizziness or imbalance
II Occasional and mild dizziness or imbalance
III Persistent or moderate vertigo or imbalance
IV Persistent and severe dizziness or imbalance, disturbing daily life
Gardner–Robertson grade
Grade Hearing level Pure Tone
Average (dB)
Speech discrimination score (%) The present case had serviceable hearing
loss in the right ear, that is, grade II
I Good to excellent 0–30 70–100
II Serviceable 31–50 50–69
III Non-serviceable 51–90 5–49
IV Poor 91–maximum 1–4
V None/Deaf Non-testable 0
V None/Deaf Non-testable 0
House–Brackmann scale for evaluation of facial nerve function
Grade Appearance Forehead Eye Mouth The present case had grade II appearance,
grade I: forehead, eye, and mouth
I Normal Normal Normal Normal
II Slight weakness normal
resting tone
Moderate
to good
movement
Complete closure
minimal effort
Slight
asymmetry
III Nondisfiguring weakness
normal resting tone
Slight to
moderate
movement
Complete closure
maximal effort
Slight weakness
maximal effort
IV Disfiguring weakness
normal resting tone
None Incomplete
closure
Asymmetric
with maximal
effort
V Minimal movement
asymmetric resting tone
None Incomplete
closure
Slight
movement
VI Asymmetric None None None
[Downloaded free from http://www.journalofcurrentoncology.org on Wednesday, February 23, 2022, IP: 10.232.74.27]
3. Patro, et al.: SRS ROSE case Vestibular Schwannoma
70 70 Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021
x 13 mm, with an intra-canalicular extension being 11 mm
x 9 mm [Figure 1B]. The lesion appeared hypointense on
both T1- and T2-weighted sequence; there was minimal
hyperintensity on FLAIR sequence and it was touching
the brainstem. Superiorly, the lesion was indenting the
cisternal component of the right V cranial nerve and
the right superior cerebellar artery. Laterally, the lesion
was indenting the right middle cerebellar peduncle and
the adjacent portion of the right cerebellar hemisphere.
The right VII and VIII cranial nerves were not separately
visualized from the lesion. There was no significant mass
effect on the right IX, X, and XI cranial root complex and
no significant effacement of the fourth ventricle. The Fast
Imaging Employing STeady-state Acquisition (FIESTA)
sequence showed the ice-cream cone appearance of
the lesion that was impending the fifth cranial nerve
[Figure 1C]. The features cited earlier were suggestive of
right-sided VS.
Grading of Vestibular Schwannoma
TherearevariousgradingsystemsforVS,suchasKoosgrading
system, House grading system, and Samii grading system.[2]
In the present case, as the tumor was reaching the brainstem
surface but not deforming the brainstem surface or shifting
the fourth ventricle, the tumor was grade III as per Koos
grading system, grade III as per House grading system, and
T3b as per Samii grading system as is seen in Table 2.
Line of Treatment
The treatment of VS includes observation, surgery, SRS,
or SRT.
Surgical Consultation
NeurosurgicalopinionfavoredhearingpreservationastheVII
and VIII cranial nerve roots not separated out on imaging.
Figure 1: CT and MRI images of Vestibular Schwannoma. (A) CT scan of the case depicting widening of the acoustic porous. (B) FSPGR sequence
of the same patient showing the lesion at the right cerebellopontine angle. (C) FIESTA sequence of the same patient showing the lesion impending
the fifth cranial nerve
Table 2: Tumor grading in vestibular schwannoma
Tumor description Tumor
size (CPA
maximum
diameter)
Stekers House Koos Smaii Present case
Confining to IAC 0 (intra-
canalicular)
Tube
type
Intra-canalicular I T1 Tumor size
10mm, House
Grade 3,
Koos grade III
and
Samii T3b.
Surpassing IAC ≤ 10mm Small Grade 1 (small) II T2
Tumor-occupying CPA ≤ 15mm Grade 2
(medium)
T3a
≤ 20mm Mild
Tumor-occupying CPA and contacting the brain stem
without compression
≤ 30mm Grade 3
(moderately
large)
III T3b
Tumor compressing the brain stem ≤ 40 Large Grade 4 (large) IV T4a
Severe brain stem displacement and deformation of the
fourth ventricle under tumor compression
40mm Huge Grade 5 (giant) T4b
[Downloaded free from http://www.journalofcurrentoncology.org on Wednesday, February 23, 2022, IP: 10.232.74.27]
4. Patro, et al.: SRS ROSE case Vestibular Schwannoma
Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021 71
Points in Favor of Choosing Radiation
The tumor was very small (maximum size 2.1 cm), solid and
the VII and VIII cranial nerves were not visualized separately.
The preservation of hearing and facial nerve functions were
the salient points that were the main reasons of choosing
radiation for this patient. As per the ISRS practice guidelines,
SRS was opted because it fulfilled the criteria of tumor
diameter 3 mm, no or mild brain stem compression.[3]
Treatment Decision by the Tumor Board
The patient details were put in the tumor board for a
decision regarding the line to treatment. After a group
discussion with the neurosurgeon, the radiation oncologist
and the board decided to plan for SRT.
Discussion with the Patient
The patient was explained about the bouquet of treatment
options, such as observation, surgery, and radiotherapy, and
the complications and outcome of each procedure. Further,
the radiation treatment procedures, hearing preservation,
imaging, and follow-up were also explained to the patient.
Counseling of the Patient
The patient was counseled regarding the tumor response
to radiation, the need for surgery in the future, and post-
radiotherapy pain.
Patient’s Preference
The patient opted for radiation, as his major concerns
were hearing preservation and trigeminal and facial nerve
weakness besides tumor control.
Dose Selection
As per ISRS practice guidelines, there is a strong consensus
to treat a newly diagnosed small size VS with single-
fraction SRS. In case of tumor abutting, the trigeminal
nerve fractionated SRT can be preferred.[4]
As per the
University Hospital of Wales protocol, a hypofractionated
SRT should be used in a VS case abutting the trigeminal
nerve.[4]
Thus, it was planned to conduct fractionated SRT
for this patient with a marginal dose of 25Gy in 5fractions
@ 5Gy/fraction as per the two guidelines cited earlier.
Decision of Radiotherapy Tumor Board
Fractionated radiotherapy was planned to a marginal
dose of 25Gy in 5fractions @ 5Gy/fraction as per the
ISRS practice guidelines.
Radiotherapy Planning
Here, we describe the steps of treatment of VS from
simulation to plan execution
Step 1: Computed tomography simulation
During simulation, the patient was set up in the supine
position with a neutral neck position and immobilization
was done using FRAXION thermoplastic mask and
a stereotactic frame [Figure 2A and B]. Fiducials were
placed on the thermoplastic mask after proper alignment
with the lasers. Intravenous contrast was given at a dose of
1ml per kg body weight. Then, a CT scan was taken from
the vertex to the neck with a CT slice thickness of 1 mm, as
is depicted in Table 3. After simulation, the DICOM CT
images were sent to our Oncentra server, which was then
imported for delineation of the target and organ at risk.
Step 2: Magnetic resonance imaging protocol
MRI of the brain of the patient was done using a 512 x 512
matrix in the neutral neck position similar to that of the CT
scan during simulation with no gap, no tilt, and a 1-mm slice
thickness as depicted in Table 3. The field of view included
the body contour along with nose, eyes, and skull. The MRI
should include the usual T1, T2, FLAIR sequences. In
addition, the 3D FSPGR was used for viewing the normal
anatomy. The cochlea, brainstem, and cranial nerves were
visualized in FIESTA sequence, and GRE sequence was
used to find out any cystic changes or hemorrhage. If a
dedicated MR simulator is available, MR simulation can be
done using this MRI protocol and the simulation process is
the same as the CT simulation mentioned earlier.
Figure 2: Immobilization of the patient using the stereotactic thermoplastic mask and frame during CT simulation in lateral view (A), the cranial view
(B), and Fusion of MRI of the patient with planning CT scan (C)
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5. Patro, et al.: SRS ROSE case Vestibular Schwannoma
72 72 Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021
Step 3: Image fusion
These acquired MRI sequences were fused with the
planning CT scan by contouring the eyes, lens, basilar
artery, and sinuses, and calcification and matching was
done using the auto-fusion technique to help in the target
and organ at risk (OAR) delineation [Figure 2C].
Step 4: Target delineation
The gross tumor seen on the CT images that was fused
with the MRI images to consider the exact extension of the
tumor was delineated as GTV. The PTV was drawn, taking
1 mm around the GTV. Smoothing of the contour was done
from the adjacent bone. Multi-planar evaluation, that is, the
evaluation of both the GTV in all the three planes—axial
[Figure 3A], coronal [Figure 3B], and sagittal [Figure 3C]
and PTV—was done in all the three planes: axial [Figure
3D], coronal [Figure 3E], and sagittal [Figure 3F].
In the present case, the GTV volume was 1.682cc and the
PTV volume was 2.766cc.
Step 5: Organ at risk delineation
The OARs for delineation included the cochlea,
brainstem, trigeminal nerve, optic chiasma, and optic
apparatus.Thecochleawascontouredinthebonewindow
setting whereas other OARs, that is, the brainstem,
trigeminal nerve, optic chiasma, and optic apparatus,
were contoured using the MRI that was fused with the
planning CT.
Step 6: Radiotherapy technique
Radiation planning can be done using any of the RT
techniques, such as Intensity Modulated Radiotherapy
(IMRT), Volumetric Modulated Arc Therapy (VMAT),
Dynamic Conformal Arc Therapy (DCARC), or
3-Dimensional Conformal Radiotherapy (3DCRT)
according to the convenience of the radiation physicist
and physician.
In the present case, planning was done using the VMAT
technique.
Step 7: Plan evaluation
After the completion of planning by the physicist, the
evaluation for the treatment plan is done using the
following indices as noted next.
Table 3: CT simulation and MRI Protocol to be followed for
vestibular schwannoma
CT simulation protocols for simulation
Supine position
Immobilization using stereotactic thermoplastic mask
Intravenous contrast at a rate of 1 mg/kg
CT scan taken from the vertex to the neck
1-mm slice thickness
MRI protocol Utility
T1/T2/FLAIR sequence Usual sequence
3D FSPGR sequence Normal anatomy
FIESTA sequence Visualization of cochlea, brainstem,
and cranial nerves
GRE sequence To see any cystic changes/ hemorrhage
512 x 512 matrix
1 mm slice thickness
No gap
No tilt
Neutral neck
Field of view should include body contour, nose, eye, and skull
Figure 3: Delineation of the GTV (pink) of Vestibular Schwannoma in the axial (A), coronal (B), and sagittal plane (C) and PTV (cyan) generation
around the GTV taking 1 mm margin in the axial (D), coronal (E), and sagittal planes (F)
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6. Patro, et al.: SRS ROSE case Vestibular Schwannoma
Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021 73
PTV coverage index
After the planning, we need to see the PTV coverage.
The prescription isodose level is usually not 100% of the
prescribed dose covering 100% of the PTV. Often, the 95% of
the prescription dose should cover 95% or higher percentage
of the PTV; otherwise, 100% of the prescription dose should
cover 95% or higher percentage of the PTV.[5]
Inthepresentcase,95%of theprescriptiondosecovers100%
of the PTV and 100% of the prescription dose covers 97.5%
of the PTV, which meets the earlier mentioned parameters
for the PTV coverage and is depicted in Table 4.
Intracranial stereotaxy organ constraints and organ at risk
coverage
Keeping in mind the desirable dose constraints to the
OAR, we need to check the dose to individual OARs.[6]
The dose desirable and dose achieved for all the OARs in
the present case is depicted in Table 5.
Conformity index
To note the conformity index of the SRS, here we used 2
types of conformity indices, that is, the RTOG conformity
index and the Paddick conformity index.[5,7]
RTOG Conformity index (CIRTOG
) is calculated using the
following formula:
CIRTOG
= Volume of Prescription Isodose / PTV volume
In this case of VS, the RTOG conformity index was 1.15
[Table 4].
Paddick conformity index (CIPaddick
) was calculated using
the following formula:
CIPaddick
= (Volume of prescription isodose in the area of
interest i.e. PTV)2
/ PTV volume x Volume of Prescription
Isodose
Here in the current case, Paddick conformity index was
1.02 [Table 4].
Homogeneity index
It is calculated using the formula:
Homogeneity Index = Maximum Dose/ Prescription Dose
In this case, the Homogeneity Index was 1.19 [Table 4].
Dose fall off
The dose fall off observation is very much needed in the
plan evaluation under the heading of gradient index. For
this we need to calculate the difference between various
isodose lines. In order to calculate the difference between
the isodose lines, we need to calculate the equivalent radius.
Equivalent radius calculation
To evaluate the dose gradient, we have to find out the
difference between the radius of various isodose lines.
However, none of the isodoses are spherical. So, we
use the following formula to calculate the equivalent
radius:
1st
: Find out the specified isodose volume
2nd
: Calculate the radius of the isodose volume by using
the formula:
V = 4/3 π r3
r = (3V/4 π)1/3
The calculation of the volume and radius of various
isodose lines in the present case is shown in Table 4.
Gradient index
The formula for calculating gradient index is as
given next.
Table 4: Various indices plan evaluation of vestibular
schwannoma in the current case
Parameter Value Desirable
Dmax 29.83Gy –
D95% 25.25Gy –
D100% 24.18Gy –
V95% 100% –
V25Gy (V100%) 97.5% –
V110% 18.26% –
V120% 0 –
V130% 0 –
PTV volume 2.776cc –
Volume of prescription isodose 3.214cc –
Volume of prescription isodose
within the PTV
3.03cc –
Maximum dose 29.83Gy –
Prescription dose 25Gy –
RTOG conformity index 1.15 1
Paddick conformity index 1.02 0.85–1
Homogeneity index 1.19 1.1–1.3
Parameter Volume Radius
100% isodose line 3.214cc 0.91 mm
80% isodose line 9.692cc 1.32 mm
60% isodose line 18.835cc 1.65 mm
50% isodose line 25.834cc 1.83 mm
40% isodose line 36.827cc 2.06 mm
Table 5: Individual OARS with its desirable dose and dose
achieved in the current case of vestibular schwannoma
Organ Desirable dose (Gy) Achieved
dose (Gy)
Right eye DMax
22.5 1
Left eye DMax
22.5 1
Right optic nerve DMax
22.5 1.2
Left optic nerve DMax
22.5 1
Optic chiasma DMax
22.5 2.8
Brainstem DMean
23–31 27.19
Right cochlea DMean
25 20.35
Left cochlea DMean
25 1.31
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7. Patro, et al.: SRS ROSE case Vestibular Schwannoma
74 74 Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021
Gradient Index = Equivalent radius of 50% isodose –
Equivalent radius of prescription isodose. Ideally, the
gradient index should be between 0.3 mm and 0.9 mm.
In the current case, the gradient index is
1.83 mm–0.91 mm = 0.92 mm, which is close to the ideal
gradient index.
Distance between various isodose lines
The various isodose lines are depicted in Figure 4A.
The ideal difference between 80% and 60% isodose lines
should be 2 mm.[8]
In the current case, it is 1.65 mm–1.32 mm = 0.33 mm.
The ideal difference between 80% and 40% isodose lines
should be 8 mm.
In the present case, it is 2.06 mm–1.32 mm = 0.74 mm.
Beam arrangement
The arrangement of the beams [Figure 4B–D] was
done such that there is adequate coverage of the target
while giving a lower dose to the OARs. It should be
noted that the beams should not pass through the
ipsilateral eye.
Step 8: Quality assurance
A mechanical isocenter check was done using the Winston
Lutz test, and the point dose verification was done while
maintaining the tolerance as 1 mm.[9]
Step 9: Dry run
Treatment verification consists of setup reproduction,
isocenter verification, and clinically verifying each
treatment field: check beam clearance, check any
interlock, MLC interlock and potential Monitor Unit
(MU) problems, and then clearly mark the immobilization
devices after a successful dry run.
Step 10: Premedication protocol
Prior to the start of the treatment premedication was
delivered in the form of tablets as described next: all
starting the day before the start of RT treatment.
Figure 4: Isodose lines: 100% (red), 80% (green), 60% (yellow), 50% (blue), and 40% (pink) in (A) and beam arrangement in axial (B), coronal (C),
and sagittal view (D) for the current case of Vestibular Schwannoma
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8. Patro, et al.: SRS ROSE case Vestibular Schwannoma
Journal of Current Oncology ¦ Volume 4 ¦ Issue 2 ¦ July-December 2021 75
Tablet Dexamethasone 8 mg thrice daily
Tablet Ondansetron 8 mg thrice daily
Tablet pantoprazole 40 mg once daily
If thepatientisdiabetic,properdiabeticcareneedstobedone.
Step 11: Set up verification and treatment delivery
It includes cone beam CT correction [Figure 5A] and
hexapod corrections [Figure 5B]. After all the corrections
are done, the treatment is delivered.
Step 12: Postmedication
It is an optional protocol that usually includes antiemetics,
proton pump inhibitors, and tapering the dose of steroids
over a week.
Step 13: Advice and follow-up
After the completion of the treatment, the patient was
usually advised to follow up after six months for imaging.
Radiotherapy outcome grading for the VS was done as
per the consensus in the 7th International Conference on
acoustic neuroma.[2]
Supplementary File
Here, we also provide the VS SRS Plan Evaluation sheet as
a supplementary file that will help in proper and accurate
plan evaluation for every SRS case of VS.
Conclusion
This article conceptualizes and acts as an easy guide
for the beginners for the stereotactic radiation planning
for VS.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
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of vestibular schwannomas: An interdisciplinary challenge. GMS
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et al. Stereotactic radiosurgery for vestibular schwannoma:
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4. Galloway L, Palaniappan N, Shone G, Hayhurst C. Trigeminal
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8. Kocher M, Soffietti R, Abacioglu U, Villà S, Fauchon F,
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Figure 5: Treatment verification. (A) Cone beam computed tomography correction of the patient during the treatment. (B) Hexapod correction of the
same patient during the treatment
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9. Patro, et al.: SRS ROSE case Vestibular Schwannoma
VESTIBULAR SCHWANNOMA SRS PLAN EVALUATION
1. NAME UMR
2. COMORBIDITY AGE
3. DIAGNOSIS SIDE
4. IMAGING A. SIDE AND SIZE
B.
INTRACANALICULAR PART LENGTH
C.
BRAINSTEM COMPRESSION
D.
TRIGEMINAL COMPRESSION
E. BONY EROSION ON CT
F. HYDROCEPHALUS
G. 7/8TH
NERVE STATUS
5. KOOS GRADING I II III IV
6. GARDNER-ROBERTSON HEARING
GRADES
I II III IV V
7. HOUSE-BRACKMAN SCALE OF
FACIAL FUNCTION
I II III IV V VI
8. TINNITUS GRADING I II III IV V
9. VERTIGO GRADING I II III IV V
10. ANY TRIGEMINAL / PAIN
DISTRIBUTION
PAIN
SCORE
11. SURGERY OPINION
12. PATIENT PREFERENCE
13. PRIOR SURGERY YES NO TYPE INTERVAL
14. PRIOR SRS YES NO DOSE INTERVAL
15. CTV VOLUME PTV MARGIN PTV
VOLUME
16. PLAN TYPE-[3DCRT/VMAT/DCR/
IMRS]
17. MONITOR UNITS
18. 1. PRESCRIBED MARGINAL ISODOSE
2. D MAX
3. D95%
4. D100%
5. V95%
6. V100%
7. V120%
8. V130%
9. DISTANCE BETWEEN 80% ISODOSE AND 60% ISODOSE-[2mm]
10. DISTANCE BETWEEN 80% ISODOSE AND 40% ISODOSE-[8mm]
11. CONFIRMITY INDEX [IDEAL 1] VOLUME OF PRESCRIPTION ISODOSE/VOLUME OF PTV
12. HOMOGENITY INDEX [BETWEEN 1.1–1.3] - MAX DOSE/ PRESCRIPTION DOSE
13. GRADIENT INDEX- [BETWEEN 0.3–0.9] [RAD OF PRESCRIPTION ISODOSE – RAD OF HALF PRESCRIPTION
ISODOSE]
19. BRAIN-GTV [12Gy volume] 10CC [4Gy volume] 20CC-MULTIPL FRACTION
20. OAR SINGLE FRACTION 5 FRACTIONS ACHIEVED
1. RIGHT EYE MAX8Gy MAX 22.5Gy
2. LEFT EYE MAX8Gy MAX 22.5Gy
3. RIGHT OPTIC NERVE MAX8Gy MAX 22.5Gy
4. LEFT OPTIC NERVE MAX8Gy MAX 22.5Gy
5. OPTIC CHIASM MAX8Gy MAX 22.5Gy
6. BRAIN STEM MAX 15Gy MAX 31Gy
7. RT. COCHLEA MEAN 9Gy MEAN 25Gy
8. LT. COCHLEA MEAN 9Gy MEAN 25Gy
Supplementary file
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