Method for calculating dose when lung tissue lies in the treatment field

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiological Dosimetry

Background:

• Accurate absorbed dose calculation in the lung is critical for radiation therapy.
• Increased transmission of x-ray and gamma radiation through the lung can lead to significant dose inaccuracies.
• Existing methods may not fully account for lung transmission effects.

Purpose of the Study:

• To describe a method for calculating the absorbed dose in the lung and tissues beyond the lung.
• To develop and validate a correction factor for increased lung transmission of x-ray and gamma irradiation.
• To demonstrate the clinical applicability of the dose calculation technique.

Main Methods:

• Developed a correction factor for absorbed dose calculation.
• The factor is dependent on beam energy, field area, lung density, and tissue depth.
• Validated calculations using measurements in an Alderson phantom.

Main Results:

• Calculated absorbed dose in lung and beyond lung, considering increased lung transmission.
• Correction factor effectively accounts for variations in beam energy, field area, lung density, and depth.
• Measurements and calculations showed agreement within 3% in the Alderson phantom.

Conclusions:

• The described technique provides accurate absorbed dose calculations in the presence of increased lung transmission.
• The validated correction factor enhances precision in radiation therapy planning involving lung irradiation.
• This method offers a practical approach for improving dose delivery accuracy in clinical settings.