Comparing radiation treatments using intensity-modulated beams, multiple arcs, and single arcs

Area of Science:

• Radiation Oncology
• Medical Physics

Background:

• Intensity-modulated radiation therapy (IMRT) is a standard technique.
• Newer arc-based techniques like intensity-modulated arc therapy (IMAT) and arc-modulated radiation therapy (AMRT) aim to improve treatment efficiency and efficacy.

Purpose of the Study:

• To perform a dosimetric comparison of IMRT, multiarc IMAT, and single-arc AMRT.
• To evaluate the clinical advantages and shortcomings of each technique.

Main Methods:

• Twelve patient cases (head-and-neck, brain, lung, prostate) were selected.
• IMRT, IMAT, and AMRT plans were generated for each case using consistent planning constraints and parameters.

Main Results:

• Multiarc IMAT demonstrated the highest plan quality.
• Single-arc AMRT achieved dose distributions comparable to IMRT, particularly for complex head-and-neck and brain cases.
• Both AMRT and IMAT effectively spared normal tissues without compromising target coverage, with some cases showing reduced total dose to surrounding normal tissues.

Conclusions:

• IMAT delivers highly uniform and conformal dose distributions, ideal for large, complex targets, with a delivery time similar to IMRT.
• AMRT offers results comparable to IMRT but with significantly faster treatment delivery times.