1.Stereotactic Radiosurgery (SRS)
SRS is a precise and focused delivery of a single, high dose of irradiation to a small and critically located intracranial volume while sparing normal structure
2.Stereotactic Body Radiation Therapy (SBRT)
SBRT is a treatment procedure similar to SRS, except that it deals extra-cranial radiosurgery
3.Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
1.Stereotactic Radiosurgery (SRS)
SRS is a precise and focused delivery of a single, high dose of irradiation to a small and critically located intracranial volume while sparing normal structure
2.Stereotactic Body Radiation Therapy (SBRT)
SBRT is a treatment procedure similar to SRS, except that it deals extra-cranial radiosurgery
3.Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
Flattening Filter Free (FFF) mode
FFF beam is produced without the use of flattening Filter
In the 1990s, several groups studied about FFF high-energy photon beams. The main interest for that, is to increase the dose rate for radiosurgery or the "physics interest”.
Need of increase in dose rate from traditional 300-600 to 1400-2400MU/min to overcome time-inefficiency and to improve patients comfort specially in SRS/SBRT
Conventional radiotherapy treatments are delivered with radiation beams that are of uniform intensity across the field (within the flatness specification limits). Wedges or compensators are used to modify the intensity profile to offset contour in irregularities and produce more uniform composite dose distributions such as in techniques using wedges. This process of changing beam intensity profile to meet the goals of a composite plan is called intensity modulation
IMRT refers to a radiation therapy technique in which nonuniform fluence is delivered to the patient from any given position of the treatment beam to optimize the composite dose distribution. The optimal fluence profiles for a given set of beam directions are determined through inverse planning. The fluence files thus generated are electronically transmitted to the linear accelerator, which is computer controlled, to deliver intensity modulated beams (IMBs) as calculated.
Conventional radiotherapy treatments are delivered with radiation beams that are of uniform intensity across the field (within the flatness specification limits). Wedges or compensators are used to modify the intensity profile to offset contour in irregularities and produce more uniform composite dose distributions such as in techniques using wedges. This process of changing beam intensity profile to meet the goals of a composite plan is called intensity modulation
IMRT refers to a radiation therapy technique in which nonuniform fluence is delivered to the patient from any given position of the treatment beam to optimize the composite dose distribution. The optimal fluence profiles for a given set of beam directions are determined through inverse planning. The fluence files thus generated are electronically transmitted to the linear accelerator, which is computer controlled, to deliver intensity modulated beams (IMBs) as calculated.
The vital importance of imaging techniques in radiation oncology now extends beyond diagnostic evaluation and treatment planning. Radiotherapy requires input from imaging for treatment planning and execution, when the treatment target is not located on the surface and, inspection and visual confirmation are not feasible. Traditional radiotherapy practices incorporate use of anatomic surface landmarks as well as radiologic correlation with 2D imaging in the form of port films or fluoroscopic imaging. Targets to be irradiated and normal tissues to be spared are delineated on CT scans in the planning process. Recent technical advances have enabled the integration of various imaging modalities into the everyday practice of radiotherapy directly at the linear accelerator. IGRT seeks to address geometric uncertainties in dose placement for target and normal tissues. It has become a routine part of current RT practice. Safe application of IGRT technology requires additional training and careful integration into the clinical process. IGRT reveals changes in anatomy during treatment which challenges conventional practices. IGRT facilitates the precise application of specialized irradiation techniques with narrow safety margins to radiosensitive organs.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
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.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
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.
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.
2. Introduction: The systems are designed from the
ground up to
–integrate high-precision radiation dose delivery at a high dose
rate
–precise tumor localization using image-guided radiotherapy
(IGRT)
–deliver high-precision conformal doses to irregularly shaped
tumors while sparing adjacent organs at risk,
Each modality is distinguished by the beam produced and its
modeling, treatment delivery, multileaf collimators (MLCs),
applicators, dose rate, specialized treatment planning, and IGRT
techniques used
5. 5
BRAINLAB NOVALIS AND THE NOVALIS Tx
(Image courtesy of Brainlab AG)
The Novalis radiosurgery platform
The linac is a Varian accelerator
whereas the beam-shaping device, the
localization and tracking system, and
the treatment planning system (TPS)
are all Brainlab components for the
Novalis
The Novalis radiosurgery family
delivers noninvasive, frameless,
shaped-beam treatments for cancerous
and noncancerous conditions of the
entire body
6. 6
THE NOVALIS:KEY FEATURES AND COMPONENTS
Novalis® radiosurgery accessories
Varian/Brainlab Novalis® Tx radiosurgery system
7. 7
THE NOVALIS:KEY FEATURES AND COMPONENTS
• The Novalis Tx system includes:
• Energy: 6 to 20 MV, a special SRS 6 MV photon beam, going through a
thinner flattening filter, is used, and the dose rate is 1000 monitor
units (MU) per minute
• Tungsten120-leaf high-definition (HD120®) MLC. It has 32 leaf pairs
with 2.5 mm leaf width (projection at the isocenter),
• surrounded by 28 leaf pairs of 5-mm projection width
• iPlan RT for treatment planning(Pencil Beam (PB) or Monte Carlo
(MC));
• ExacTrac and 6D robotic couch for image-guided patient positioning,
correcting directional inaccuracies and rotational misalignments
8. 8
THE NOVALIS:KEY FEATURES AND COMPONENTS
• PortalVisionTM, which offers treatment verification during dose delivery,
and dosimetry QA for verifying system performance
• On-Board Imager® (OBI), providing cone beam computed tomography
(CBCT) for volumetric soft tissue discrimination and kilovoltage (kV)
fluoroscopic imaging for respiratory motion verification (Brainlab)
• Patient setup does not rely on source-to-skin distance (SSD) information;
it uses external body markers and the ExacTrac system
• The ODI is not blocked and SSD could be used in patient setup for
conventional cases ?
• For even smaller circular targets (trigeminal neuralgia), 1 cm or less,
stereotactic cones are used (the penumbra is reduced, and the dose
gradient is steep).
9. 9
THE NOVALIS:ExacTrac
• It allows for patient setup with high-resolution stereo x-ray imaging
• ExacTrac relies mostly on bony anatomy registration. For soft tissue
targets, implanted fiducial markers are needed for localization
• The ExacTrac X-Ray 6D system is mainly an integration of 2
subsystems:
1. an infrared (IR)-based optical positioning system (ExacTrac) for initial patient
setup and precise control of couch movement, and
2. a radiographic kV x-ray imaging system (X-Ray 6D) for position verification and
readjustment based on the internal anatomy or implanted fiducial
10. 10
THE NOVALIS: The Infrared Tracking System
• The infrared tracking component of the
ExacTrac X-Ray 6D system includes 2
stereoscopic IR cameras, passive IR
reflecting spheres placed on a patient’s
surface, and a reference device (the
reference star) that contains 4 reflective
circle.
• The IR cameras, mounted from the ceiling,
record the positions of IR reflective markers
on the patient’s surface
• The reference star attached to the couch, is
used to precisely determine the couch’s
movement
11. 11
THE NOVALIS: The Infrared Tracking System
• During treatment, the real-time data obtained from this IR system is used to monitor
the patient’s position for unexpected changes and/or to track motion for gated delivery
12. 12
THE NOVALIS:ExacTrac kV X-Ray System
• ExacTrac consists of two kV x-ray units
in the treatment room floor and two
ceiling-mounted amorphous silicon flat
panel detectors
1. the x-ray tubes and corresponding
detector panels are in fixed positions,
2. the x-rays project in an oblique
direction relating to the patients,
3. the source isocenter and source
detector distance is relatively large
(2.24 and 3.62 meters, respectively).
13. 13
THE NOVALIS:Respiratory gating
• The ExacTrac Adaptive
Gating system uses
stereoscopic kilovoltage
radiographs for patient
positioning and the IR
marker detection system for
respiratory tracking and
gating of the treatment
beam
15. 15
ACCURAY ROBOTIC RADIOSURGERY: THE CYBERKNIFE
CyberKnife® VSI robotic radiosurgery system
CyberKnife® M6TM radiosurgery suite with the
InCiseTM MLC
16. 16
ACCURAY ROBOTIC RADIOSURGERY: THE CYBERKNIFE
The target is fixed and is made of a
tungsten alloy. The system has a straight-
through waveguide, steering coils, no
flattening filter, sealed air-filled ionization
chambers, a primary collimator, and a
secondary set having circular apertures with
diameters ranging from 5 to 60 mm at a
source-to-axis distance (SAD) of 80 cm
It consists of two stacked hexagonal banks
of tungsten blades forming a
dodecagonal(?) opening
17. 17
THE TRILOGY SYSTEM
The Varian Trilogy® is a comprehensive
delivery system. It can be used for 3-D
conformal radiation therapy (CRT), IMRT,
IGRT, dynamic adaptive radiotherapy
(DART), and both intracranial and
extracranial stereotactic techniques
The Trilogy platform combines a
multimodality linac with MLC, advanced
imaging capabilities, patient immobilization,
target tracking and motion management,
and treatment planning (Eclipse)
18. 18
THE TRUEBEAM SYSTEM
This platform for image-guided
radiotherapy and radiosurgery is a fully
integrated system (imaging, beam delivery,
and motion management) designed from
the ground up to treat moving targets and
to improve operation, precision,
and speed
The system also delivers Varian’s new gated
RapidArc® radiotherapy, which
compensates for tumor motion by
synchronizing imaging with dose delivery
during a continuous rotation around the
patient.
19. 19
THE TRUEBEAM SYSTEM
This platform for image-guided
radiotherapy and radiosurgery is a fully
integrated system (imaging, beam delivery,
and motion management) designed from
the ground up to treat moving targets and
to improve operation, precision,
and speed
The system also delivers Varian’s new gated
RapidArc® radiotherapy, which
compensates for tumor motion by
synchronizing imaging with dose delivery
during a continuous rotation around the
patient.
Editor's Notes
The systems are designed from the ground up to
integrate high-precision radiation dose delivery at a high dose rate and precise tumor localization using image-guided radiotherapy (IGRT
deliver high-precision conformal doses to irregularly shaped tumors while sparing adjacent organs at risk, which makes them suitable for dose escalation protocols, potentially resulting in higher tumor control rates and fewer side effects
Different manufacturers have adopted different technologies and incorporated different hardware and software tools into their designs. Each modality is distinguished by the beam produced and its modeling, treatment delivery, multileaf collimators (MLCs), applicators, dose rate, specialized treatment planning, and IGRT techniques used. Some of the commercially available technologies are different from the classical C-arm type accelerator (CyberKnife, Hi-ART, ViewRay, and Vero).
6D couch very important for SIMT cases.
The Novalis® radiosurgery platform, featuring Novalis and Novalis Tx systems, brings together technologies from Varian Medical Systems, Inc. (Palo Alto, California) and Brainlab AG (Feldkirchen, Germany) to create a fully integrated SRS/SBRT solution (Solberg et al. 2001)
The Novalis radiosurgery family delivers noninvasive, frameless, shaped-beam treatments for cancerous and noncancerous conditions of the entire body.
The high-definition shaped beam technology dynamically conforms the treatment beam to the lesion while protecting surrounding healthy tissue.
Although these machines do come with a stereotactic frame for SRS, the intracranial radiosurgery treatments are usually achieved without the invasive frame. With the use of robust IGRT methods and immobilization techniques, the quality of the SRS treatment is not compromised
The Novalis radiosurgery family delivers noninvasive, frameless, shaped-beam treatments for cancerous and noncancerous conditions of the entire body. The treatment of a variety of intracranial targets is monitored by specific software tools. X-ray images are acquired and verified with the ExacTrac® x-ray 6D IGRT imaging system, during patient setup and treatment delivery. They provide detection and visualization of displacements.
Some of the features of the Novalis system include an energy of 6 MV; a 52-leaf micro-MLC (Brainlab m3® high-resolution MLC), allowing for the delivery of highly conformal dose, improved margins, and better protection of surrounding tissue; Brainlab iPlan® Radiation Therapy (RT) Treatment Plan for treatment planning; and ExacTrac for accurate and automated patient positioning (Brainlab). The system includes a full range of stereotactic hardware for immobilization, setup, and QA, such as head rings, conical collimators, and target positioning hardware (Figure 4.3).
To increase the steepness of the dose, the penumbra of the collimator system must be minimized. For radiosurgery, the recommended limit for dose gradient in the beam penumbra (from 80% to 20%) is at least 60%/3 mm. Most commercially available MLCs have a penumbra specification from 4 to 8 mm. The m3 micro-MLC has an effective penumbra of less than 3 mm for all SRS field sizes and meets the SRS requirements (Schell et al. 1995). The dose can then be tailored to the shape of the lesion while sparing healthy tissue.
ExacTrac includes two different stereoscopic imaging systems. The real-time infrared (IR) system measures the position of the patient’s surface. It is used for initial patient positioning, monitoring patient position, and tracking patient motion during gated treatment delivery. ExacTrac also uses the IR images to move the 6D robotic couch with submillimeter precision and accuracy. The X-ray imaging system (ETX) gives accurate localization based on internal anatomy and/or implanted fiducials.
It also comes with an integrated optical infrared tracking system for continuous monitoring of patient position throughout treatment. The system uses a pair of infrared video cameras to triangulate on an external set of fiducial markers, the Body Marker Array, which is affixed to the anterior thorax and/or abdomen of the patient (Brainlab). It is calibrated in the treatment reference space of the linear accelerator, and it controls the treatment couch motions, guiding the lesion to the linac isocenter.
Two stereoscopic IR cameras, mounted from the ceiling, record the positions of IR reflective markers on the patient’s surface. From these images, the system computes the 3D position of the patient. The IR markers are positioned identically on the patient during CT simulation and at treatment time. Based on the treatment plan isocenter, the ExacTrac software calculates the shifts and rotations needed to bring the patient to the correct treatment location. Figure 3 shows the IR markers on a patient and the computer screen after alignment. This initial positioning is followed by more accurate X-ray positioning. During treatment, the real-time data obtained from this IR system is used to monitor the patient’s position for unexpected changes and/or to track motion for gated delivery. Because IR positioning is based on the patient’s external surface, it is inherently more accurate for cranial targets than for body targets.
The reference star is a reference against which the movement of patient mounted markers is measured, and also to track couch location during the patient positioning process
During treatment, the real-time data obtained from this IR system is used to monitor the patient’s position for unexpected changes and/or to track motion for gated delivery. Because IR positioning is based on the patient’s external surface, it is inherently more accurate for cranial targets than for body targets.
The IR system samples marker positions at a frequency of 20 Hz and therefore may also be used to monitor patient motion. The y-axis is a 3-dimensional (3D) composite of the combined motion of 5 markers placed on a patient’s chest
Two x-ray images are obtained after a patient is initially setup with the ExacTrac (infrared) system. These images are then compared with the patient’s 3-dimensional (3D) CT simulation images with the corresponding isocenter in terms of digital reconstructed radiography (DRR). The software provides several options for matching the images. The manual match and the 3D (3 degrees of freedom) fusion methods assume that the patient was setup with no rotational offsets
Although it may be possible to track lung tumors directly using plane radiography,25 the ExacTrac Adaptive Gating system is currently designed to be used with radiopaque fiducial markers implanted near the target isocenter
These markers are implanted before treatment planning begins and should be placed close enough to the target anatomy so that they can be seen within the field of view of the x-ray localization system at the time of treatment. It is assumed that the spatial relationship between markers and target anatomy will remain relatively fixed
The 3D movement of the patient’s anterior surface is tracked via the IR markers and the anterior-posterior (A-P) component of this trajectory is used to monitor breathing motion. Target position is expected to be correlated with this breathing motion
The 3D movement of the patient’s anterior surface is tracked via the IR markers and the anterior-posterior (A-P) component of this trajectory is used to monitor breathing motion. Target position is expected to be correlated with this breathing motion
The ExacTrac system plots breathing motion vs. time, and a gating reference level is specified on this breathing trace (Fig. 4). The gating level is the amplitude of the breathing trace at which the kV x-ray images for patient localization will be triggered
The images are obtained sequentially at the instant the breathing trace crosses this level during the exhale phase. Because the patient will be localized based on these images, the gating level should be set at the same phase in the breathing cycle at which the planning CT data was obtained.
Within each image, the user locates the positions of the implanted fiducials. From these positions, the system reconstructs the 3D geometry of the implants and determines the shifts necessary to bring them into alignment with the implants’ orientation as determined from the planning CT. These localization shifts are then made to the patient just as with the basic ExacTrac system. Once the patient has been positioned in this way, the target will pass through the linac isocenter as the breathing trace passes through the gating level
Finally, a gating window (Fig. 4) is determined. The system can gate the beam in both inhale and exhale phases of the breathing cycle; however, the treatment beam is gated during the exhale phase because hysteresis of target motion has been observed during the breathing cycle.41 Localization is also performed in the exhale phase; therefore, it is expected that the target is most accurately positioned here
The CyberKnife is a frameless robotic system for radiosurgery that consist of a lightweight linear accelerator, a robotic delivery system, and noninvasive image-guided localization to delivers a great number of independently targeted, non-coplanar radiation beams with high precision under continuous X-ray and optic image guidance for motion management.
The primary control point of the CyberKnife operational system is a graphical user interface delivery system that initiates and monitors operations of the different components. During treatment delivery, the software monitors the system status and safety controls, reports errors, manages the patient database and records treatment data log files for post-treatment assessment and analysis.
The target localization system (TLS) is composed of two orthogonally positioned diagnostic X-ray sources and two corresponding amorphous silicon plates. They provide near real-time digital X-ray images of the patient in the treatment position.
During patient setup, the target position is determined (relative to nearby bony anatomy or, in extracranial treatments, implanted fiducials) by comparison of the left anterior oblique (LAO) and right anterior oblique (RAO) X-rays, with digitally reconstructed radiographs (DRRs) in the same LAO and RAO positions derived from the preoperative CT scans.
The system uses a movable treatment table to position the patient before treatment. This operating table can be moved automatically along five axes (three translations and two rotations). The final rotational movement (yaw) is applied manually.
The newly developed robotic couch (RoboCouch Patient Positioning System, Accuray Incorporated) can be adjusted entirely robotically (i.e., based on image information and without intervention by the user) in all 6 axes
The target is fixed and is made of a tungsten alloy. The linac is mounted on a highly maneuverable robotic manipulator arm
This manipulator can position the linac with 6 degrees of freedom and 0.12-mm precision. The system has a straight-through waveguide, steering coils, no flattening filter, sealed air-filled ionization chambers, a primary collimator, and a secondary set having circular apertures with diameters ranging from 5 to 60 mm at a source-to-axis distance (SAD) of 80 cm. Since 2008, a collimator
It consists of two stacked hexagonal banks of tungsten blades forming a dodecagonal opening. It can be set to 12 circular field sizes (from 5 to 60 mm, nominally equal to the system’s 12 fixed collimator sizes). This allows the use of several different aperture sizes in a single treatment plan, optimizing dosimetry and treatment time for SRS. The beam flatness is within 14% when measured at a depth of 5 cm, a SAD of 80 cm, and a secondary collimator of 4 cm.
Varian’s linac is characterized by a gridded electron gun that controls the beam from full on to full off in 2 to 3 ms, a waveguide, and an achromatic three-field bending magnet coupled with a 3-D servo-system and a solenoid (Varian Medical Systems)
Real-time beam steering and dual sealed ion chambers working as a feedback loop to keep this steering accurate result in a tightly focused beam with optimal flatness, symmetry, and dosimetry. The 2-mm circular focal spot allows for steeper dose gradients and sharper portal images.
new Varian linacs is an energy switch that optimizes the guide length to deliver the highest dose rates for all energies up to 1000 MU/min for stereotactic beams at maximum dose depth (dmax) and 100-cm SAD
The Trilogy has a separate small filter optimized for small field treatments in the 6-MV high dose rate mode (HDRM) of 1000 MU/min
The MillenniumTM MLC is a two-bank, 120-leaf collimator with 5-mm leaf widths at the isocenter for the central 20 cm of the 40 × 40 cm field. The small leaf resolution makes it suitable for small lesions as in stereotactic treatments. Fast leaf speed and interdigitation capabilities result in shorter treatment times. The MLC operates in static, dynamic (step-and-shoot and sliding window delivery), and conformal arc modes. For stereotactic techniques, the Trilogy Tx model comes with the HD120 MLC and conical collimators. The maximum field size for SRS is 15 × 15 cm in HDRM, and the maximum dose per field is 6000 MUs (Varian Medical Systems)
Varian’s linac is characterized by a gridded electron gun that controls the beam from full on to full off in 2 to 3 ms, a waveguide, and an achromatic three-field bending magnet coupled with a 3-D servo-system and a solenoid (Varian Medical Systems)
Real-time beam steering and dual sealed ion chambers working as a feedback loop to keep this steering accurate result in a tightly focused beam with optimal flatness, symmetry, and dosimetry. The 2-mm circular focal spot allows for steeper dose gradients and sharper portal images.
new Varian linacs is an energy switch that optimizes the guide length to deliver the highest dose rates for all energies up to 1000 MU/min for stereotactic beams at maximum dose depth (dmax) and 100-cm SAD
The Trilogy has a separate small filter optimized for small field treatments in the 6-MV high dose rate mode (HDRM) of 1000 MU/min
The MillenniumTM MLC is a two-bank, 120-leaf collimator with 5-mm leaf widths at the isocenter for the central 20 cm of the 40 × 40 cm field. The small leaf resolution makes it suitable for small lesions as in stereotactic treatments. Fast leaf speed and interdigitation capabilities result in shorter treatment times. The MLC operates in static, dynamic (step-and-shoot and sliding window delivery), and conformal arc modes. For stereotactic techniques, the Trilogy Tx model comes with the HD120 MLC and conical collimators. The maximum field size for SRS is 15 × 15 cm in HDRM, and the maximum dose per field is 6000 MUs (Varian Medical Systems)
Varian’s linac is characterized by a gridded electron gun that controls the beam from full on to full off in 2 to 3 ms, a waveguide, and an achromatic three-field bending magnet coupled with a 3-D servo-system and a solenoid (Varian Medical Systems)
Real-time beam steering and dual sealed ion chambers working as a feedback loop to keep this steering accurate result in a tightly focused beam with optimal flatness, symmetry, and dosimetry. The 2-mm circular focal spot allows for steeper dose gradients and sharper portal images.
new Varian linacs is an energy switch that optimizes the guide length to deliver the highest dose rates for all energies up to 1000 MU/min for stereotactic beams at maximum dose depth (dmax) and 100-cm SAD
The Trilogy has a separate small filter optimized for small field treatments in the 6-MV high dose rate mode (HDRM) of 1000 MU/min
The MillenniumTM MLC is a two-bank, 120-leaf collimator with 5-mm leaf widths at the isocenter for the central 20 cm of the 40 × 40 cm field. The small leaf resolution makes it suitable for small lesions as in stereotactic treatments. Fast leaf speed and interdigitation capabilities result in shorter treatment times. The MLC operates in static, dynamic (step-and-shoot and sliding window delivery), and conformal arc modes. For stereotactic techniques, the Trilogy Tx model comes with the HD120 MLC and conical collimators. The maximum field size for SRS is 15 × 15 cm in HDRM, and the maximum dose per field is 6000 MUs (Varian Medical Systems)
