Related Experiment Video
Updated: Jan 29, 2026
08:25
Radiation Planning Assistant - A Streamlined, Fully Automated Radiotherapy Treatment Planning System
Published on: April 11, 2018
15.9K
Monte Carlo dose verification for a single-isocenter VMAT plan in multiple brain metastases
Kento Hoshida1, Fujio Araki2, Takeshi Ohno2
1Graduate School of Health Sciences, Kumamoto University, 4-24-1 Kuhonji, Kumamoto, 862-0976, Japan.
Summary
Monte Carlo (MC) simulations are valuable for verifying dose calculations in single-isocenter volumetric modulated arc therapy (VMAT) for brain metastases. Treatment planning system algorithms like AAA and AXB may overestimate doses, especially with larger jaw settings.
Area of Science:
- Medical Physics
- Radiation Oncology
- Radiotherapy Planning
Background:
- Accurate dose calculation is critical for effective radiotherapy, particularly for complex treatments like single-isocenter volumetric modulated arc therapy (VMAT) for multiple brain metastases.
- Treatment planning systems (TPS) utilize algorithms such as the Analytical Anisotropic Algorithm (AAA) and Acuros XB (AXB) for dose calculation, but their accuracy needs verification against more precise methods.
Purpose of the Study:
- To assess the accuracy of dose calculation algorithms (AAA and AXB) in a TPS for single-isocenter VMAT plans treating multiple brain metastases.
- To compare TPS dose distributions with those obtained from Monte Carlo (MC) simulations for verification.
Main Methods:
- A multitarget phantom with acrylic balls was used to simulate multiple brain metastases.
- Seven VMAT plans were created: one multitarget plan (MTP) and six single target plans (STP) with varying jaw field settings.
- Dose distributions were calculated using AAA and AXB, and recalculated using MC simulations under identical irradiation conditions.
Main Results:
- Both AAA and AXB algorithms tended to overestimate radiation dose compared to MC simulations, particularly in the MTP and STPs with large jaw field settings.
- The study demonstrated that dose distribution in single-isocenter VMAT plans for multiple brain metastases is significantly influenced by the chosen jaw field settings.
- Discrepancies between TPS algorithms and MC simulations highlight the need for careful validation in complex treatment scenarios.
Conclusions:
- Monte Carlo (MC) simulations provide a reliable method for 3D dose verification of single-isocenter VMAT plans for multiple brain metastases.
- The findings underscore the importance of considering jaw field settings and validating TPS dose calculations against MC simulations for improved treatment accuracy.
Related Concept Videos
01:11Bioavailability Study Design: Single Versus Multiple Dose Studies
232
Bioavailability studies are essential for understanding how a drug is absorbed, distributed, metabolized, and excreted in the body. These studies assess the extent and rate at which the active pharmaceutical agent becomes available at the site of action. The design of bioavailability studies can involve single-dose or multiple-dose regimens, each with distinct advantages and limitations.Single-dose studies are the preferred approach due to their simplicity and reduced drug exposure for...
232
01:25Determination of Multiple Dosing Parameters: Loading and Maintenance Doses
236
A loading dose is an essential pharmacological strategy to rapidly achieve the target plasma drug concentration necessary for an immediate therapeutic effect. This approach is especially critical for drugs characterized by slow absorption or extended half-lives, where delaying therapeutic plasma levels could compromise treatment outcomes. By administering a loading dose, clinicians ensure a prompt onset of drug action, even for agents with complex pharmacokinetic profiles.Achieving steady-state...
236
03:00Self-Evaluation: Self-Enhancement and Self-Verification
5.8K
Social psychologists have documented that feeling good about ourselves and maintaining positive self-esteem is a powerful motivator of human behavior (Tavris & Aronson, 2008). In the United States, members of the predominant culture typically think very highly of themselves and view themselves as good people who are above average on many desirable traits (Ehrlinger, Gilovich, & Ross, 2005). Often, our behavior, attitudes, and beliefs are affected when we experience a threat to our...
5.8K
01:21Drug Accumulation During Multiple Dosing: Repetitive IV Injections
279
Calculating drug dosage and accumulation in multiple-dose regimens is crucial for achieving therapeutic efficacy while avoiding toxicity. This involves determining the plasma drug concentrations over time to optimize dosing schedules. The principle of superposition is fundamental in this process, allowing for the prediction of drug concentration in plasma following multiple doses based on single-dose data.The principle of superposition asserts that the plasma concentration-time curves from...
279
01:24Drug Accumulation During Multiple Dosing: Intermittent IV Infusions
251
Intermittent intravenous (IV) infusion is a method of drug administration where medications are delivered over short infusion periods followed by intervals of no drug delivery. This approach helps to prevent sustained high drug concentrations in the bloodstream, reducing the risk of adverse effects associated with prolonged exposure. Unlike continuous infusion, steady-state concentrations may not be achieved during a single dosing cycle but can be reached through repeated...
251
01:17Strategies of Self-Presentation II: Self-Verification
189
Self-verification is a fundamental psychological drive wherein individuals seek affirmation of their self-concept from others, striving for consistency between their internal self-view and external perceptions. This drive operates even when the self-concept is negative, influencing interpersonal behavior and feedback preferences in complex and often counterintuitive ways. Unlike the self-enhancement motive, which seeks positive evaluations, self-verification prioritizes coherence and...
189