Impact of Dose Inhomogeneity on Radiation Therapy for Lung Tumors
Author Information
Author(s): Anne Richter, Kurt Baier, Juergen Meyer, Juergen Wilbert, Thomas Krieger, Michael Flentje, Matthias Guckenberger
Primary Institution: Julius-Maximilians-University, Department of Radiation Oncology, Wuerzburg, Germany
Hypothesis
The study aims to evaluate the influence of inhomogeneous dose distributions in the presence of breathing-induced target motion and to calculate margins for motion compensation.
Conclusion
Using inhomogeneous dose distributions in treatment planning allows for smaller margins to compensate for breathing-induced target motion, resulting in lower doses to surrounding organs-at-risk.
Supporting Evidence
- Smaller margins were needed for increased dose inhomogeneity, with margins of 2.5 mm, 2.4 mm, and 1.3 mm sufficient for different dose prescriptions.
- The study found a quadratic relationship between the standard deviation of the probability density function and margin size.
- Optimal sparing of surrounding organs-at-risk was achieved for dose prescriptions between P105 and P118.
Takeaway
When treating lung tumors, using uneven doses can help doctors use less space around the tumor to make sure the treatment works well and protects healthy parts of the body.
Methodology
The study used 4D-CT examinations to generate probability density functions for ten patients and calculated the time-accumulated dose to the tumor using one-dimensional convolution simulations.
Potential Biases
The correlation between external surrogate and internal target motion may introduce inconsistencies.
Limitations
The study did not account for tissue inhomogeneities and was limited to one spatial dimension, focusing only on superior-inferior motion.
Participant Demographics
Ten patients (3 female, 7 male) with an average age of 67 years were included.
Digital Object Identifier (DOI)
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