PCXMC cone beam computed tomography dosimetry investigations

Area of Science:

• Medical Physics
• Radiological Imaging

Background:

• Cone beam computed tomography (CBCT) is a widely used imaging modality in image-guided radiation therapy.
• Quantifying the concomitant dose and associated risks from CBCT is crucial but lacks standardization, especially concerning patient size variations.

Purpose of the Study:

• To develop a generalized method for rapidly quantifying and formulating concomitant dose as a function of patient size for CBCT.
• To address the limitations of previous studies by including numerous CBCT vendors, protocols, and a wide range of patient sizes.

Main Methods:

• Utilized PCXMC (a Monte Carlo simulator) and MATLAB to create a generalized approach for dose quantification.
• Investigated the method using Varian on-board imaging protocols with 94 adult and pediatric phantoms across six age groups, varying height and mass.

Main Results:

• Concomitant radiation dose from CBCT varies significantly with patient size, with doses potentially doubling for smaller patients and halving for larger patients compared to the average.
• The developed method successfully formulates these dose variations across a wide range of patient sizes and CBCT systems.

Conclusions:

• The developed generalized method enables accurate quantification and formulation of concomitant dose variations due to patient size across diverse CBCT vendors and protocols.
• This approach facilitates the creation of a comprehensive catalogue to manage concomitant doses in various clinical scenarios, improving risk assessment in radiation therapy.