Related Experiment Video
Updated: May 28, 2026
08:34
Proton Therapy Delivery and Its Clinical Application in Select Solid Tumor Malignancies
Published on: February 6, 2019
Out-of-field neutron doses in proton therapy: from experimental characterization to a practical calculation tool
Evangelina Martínez-Francés1, Verónica Morán1, Rafael Rodriguez2
1Medical Physics and Radiation Protection Department, Clínica Universidad de Navarra, Madrid, Spain.
Physics in Medicine and Biology
|May 26, 2026
Summary
This study quantifies out-of-field neutron dose in proton therapy, developing a Python tool to estimate these doses for improved patient safety. The tool uses a linear superposition model validated by multiple detectors.
Area of Science:
- Medical Physics
- Radiation Oncology
- Nuclear Engineering
Background:
- Pencil beam scanning (PBS) proton therapy utilizes proton beams for cancer treatment.
- Out-of-field neutron dose is a significant concern in proton therapy rooms.
- Accurate estimation of neutron dose is crucial for patient safety and treatment planning.
Purpose of the Study:
- To experimentally characterize neutron dose distribution in a PBS proton therapy room.
- To analyze factors influencing neutron dose, including proton energy, gantry angle, distance, and field size.
- To develop a practical computational tool for estimating out-of-field neutron doses.
Main Methods:
- Utilized multiple detectors: ambient, bubble detectors (BDs), track-etch, thermoluminescent dosimeters (TLDs), and electronic personal dosimeters.
- Conducted measurements across various proton energies, gantry angles, field sizes, and distances from the isocenter.
- Applied Bland-Altman analysis and validated the linear superposition model for neutron dose contributions.
Main Results:
- Room symmetry varied with gantry angle; doses at 0º were lower than at 180º.
- Neutron doses showed minimal difference for small fields but increased with larger field sizes (2-22%).
- A validated Python-based calculator for out-of-field neutron dose estimation was developed.
Conclusions:
- The developed Python tool provides a practical method for estimating out-of-field neutron doses in PBS proton therapy.
- The linear superposition model accurately approximates neutron doses based on energy layer contributions.
- This tool aids in assessing and managing neutron dose for improved safety in proton therapy facilities.
More Related Videos
Related Concept Videos
02:59Biological Effects of Radiation
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...
01:17Radiation: Applications
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
01:21Dose Size and Dosing Frequency: Determination Methods
Determining the optimal dose size and dosing frequency in pharmacotherapy is crucial for achieving therapeutic effectiveness while minimizing adverse effects. This article explores the methodologies employed in determining these parameters, focusing on their significance and interplay to tailor dosing regimens.Dose Size: Dose size refers to the amount of a drug administered in a single dose. It is determined based on the drug's pharmacodynamics and pharmacokinetics properties and...