Related Experiment Video
Updated: Feb 9, 2026
08:54
Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
15.0K
Evaluation of functionally weighted dose-volume parameters for thoracic stereotactic ablative radiotherapy (SABR)
Takayuki Kanai1, Noriyuki Kadoya2, Yujiro Nakajima3
1Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Japan; Department of Radiation Oncology, Yamagata University Faculty of Medicine, Yamagata, Japan.
Summary
This study found that a 25th percentile threshold with functional V30 (fV30) best predicts radiation pneumonitis in lung SABR. Optimizing dose-volume parameters improves treatment outcomes for patients undergoing thoracic stereotactic ablative radiotherapy.
Area of Science:
- Radiation Oncology
- Medical Physics
- Pulmonary Medicine
Background:
- Radiation pneumonitis (RP) is a significant side effect of thoracic stereotactic ablative radiotherapy (SABR).
- Four-dimensional CT (4DCT)-based ventilation imaging offers potential for reducing lung dose.
- Functionally weighted dose-volume parameters may improve RP prediction over conventional metrics.
Purpose of the Study:
- To evaluate functionally weighted dose-volume parameters for predicting RP in lung SABR.
- To identify an optimal weighting method for effective planning optimization.
- To compare the predictive accuracy of functional parameters against conventional dose-volume metrics.
Main Methods:
- Analysis of 40 patients treated with lung SABR.
- Acquisition of ventilation images from 4DCT using deformable registration and Hounsfield unit-based calculation.
- Calculation of functional mean lung dose (fMLD) and functional lung V(x) (fVx) using thresholding and linear weighting methods with varying ventilation thresholds.
Main Results:
- The combination of a 25th percentile ventilation threshold and fV30 demonstrated the highest predictive accuracy for RP (AUC: 0.570).
- fV30 with the 25th percentile threshold was the best predictor among tested functional parameters.
- Conventional dose-volume parameters showed lower predictive accuracy compared to the optimal functional parameter, though not always statistically significant.
Conclusions:
- Functionally weighted dose-volume parameters, particularly fV30 with a 25th percentile threshold, are superior predictors of RP in thoracic SABR.
- Appropriate functional weighting methods are crucial for optimizing treatment planning and improving patient outcomes.
- Further research into functional lung metrics can enhance the safety and efficacy of lung SABR.
Related Concept Videos
01:25Determination of Multiple Dosing Parameters: Loading and Maintenance Doses
248
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...
248
01:15Determination of Multiple Dosing Parameters: Steady-State, Minimum and Maximum Concentrations
258
Gentamicin, an aminoglycoside antibiotic, is commonly administered via intermittent intravenous infusion to treat severe infections. An intermittent one-hour infusion of gentamicin, administered at eight-hour intervals, allows for precise control of plasma drug concentrations, minimizing toxicity while ensuring therapeutic efficacy. Pharmacokinetic principles govern the dynamics of plasma concentrations and can be mathematically described using specific equations.The plasma drug concentration...
258
01:23Mechanical Ventilation II: Invasive Ventilation
781
Ventilators are essential medical equipment used to aid patients with respiratory difficulties. Their primary function is to assist or replace spontaneous breathing by providing mechanical ventilation. There are two general classes of mechanical ventilators: negative-pressure and positive-pressure ventilators.
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
Negative-Pressure Ventilators
Negative-pressure ventilators create a vacuum around the chest or body to draw air into the lungs, simulating breathing. This method does not require an...
781
01:15Thoracic Aorta
1.8K
The thoracic section of the aorta begins at the T5 vertebra and extends to the T12 level at the diaphragm, initially progressing through the mediastinum to the left of the spinal column. Throughout its course in the thoracic segment, the thoracic aorta emits various offshoots known collectively as visceral and parietal branches. The branches that predominantly supply blood to visceral organs are termed visceral branches and include bronchial, pericardial, esophageal, and mediastinal arteries,...
1.8K
01:23Mechanical Ventilation III: Noninvasive Ventilation
614
Noninvasive positive-pressure ventilation (NIPPV), continuous positive airway pressure (CPAP), and bilevel positive airway pressure (BiPAP) are essential methods in respiratory care. These ventilation techniques offer unique benefits for patients with various respiratory conditions, providing adequate support without requiring intubation. Let's explore how each method is crucial in improving patient outcomes and enhancing respiratory therapy.
Noninvasive Positive-Pressure Ventilation...
Noninvasive Positive-Pressure Ventilation...
614
00:57Weighted Mean
6.4K
While taking the arithmetic, geometric, or harmonic mean of a sample data set, equal importance is assigned to all the data points. However, all the values may not always be equally important in some data sets. An intrinsic bias might make it more important to give more weightage to specific values over others.
For example, consider the number of goals scored in the matches of a tournament. While computing the average number of goals scored in the tournament, it may be more important to...
For example, consider the number of goals scored in the matches of a tournament. While computing the average number of goals scored in the tournament, it may be more important to...
6.4K