Effectiveness of Intensity Modulate Proton Therapy in Managing Complex Multiple Meningiomas: A Dosimetric and...

Area of Science:

• Radiation Oncology
• Medical Physics
• Neurosurgery

Background:

• Multiple meningiomas (MM) present challenges in radiation therapy, particularly in sparing nearby neurological organs at risk (OARs).
• Accurate dose delivery and OAR protection are critical for optimizing treatment outcomes and minimizing toxicity.

Purpose of the Study:

• To introduce and evaluate a novel, robust intensity-modulated proton therapy (IMPT) plan for MM.
• To compare the dosimetric and radiobiological outcomes of IMPT against helical tomotherapy (HT) for MM treatment.

Main Methods:

• Developed competing IMPT and HT plans using CT and MRI data from 24 MM patients.
• IMPT utilized a spot-assignment strategy with five static fields, robustly optimized for CTV-sum (considering setup and range uncertainties).
• Helical tomotherapy (HT) was optimized on PTV-sum, with a median prescribed dose of 50.2 GyRBE in 28 fractions.

Main Results:

• IMPT achieved clinically acceptable target coverage (D95% difference of -0.58 ± 0.57 GyRBE).
• IMPT significantly reduced maximal dose (Dmax) and mean dose (Dmean) to most OARs (p < 0.05).
• IMPT lowered integral dose to normal brain tissue by a factor of 1.37-6.97 and reduced NTCP for critical OARs (p < 0.05).

Conclusions:

• Robust target coverage is maintained with IMPT for MM treatment.
• IMPT significantly lowers OAR doses and associated normal tissue complication probabilities (NTCP) compared to HT.
• Reduced integral dose with IMPT may offer benefits for re-irradiation and decrease the risk of secondary malignancies.