Dosimetric Importance of Implementing Jaw Tracking Technique in Radiotherapy Treatment Plan Execution.

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Organs at risk (OARs) require careful dose sparing in radiotherapy to minimize toxicity.
• Dynamic Intensity Modulated Radiotherapy (D-IMRT) offers advanced dose modulation capabilities.
• Jaw Tracking Technique (JTT) is an advanced D-IMRT technique that dynamically adjusts treatment field jaws.

Purpose of the Study:

• To evaluate the dosimetric benefits of the Jaw Tracking Technique (JTT) in reducing doses to organs at risk (OARs).
• To assess the ability of JTT to achieve optimal dose coverage for the target volume.
• To compare JTT with the Static Jaw Technique (SJT) in D-IMRT for Glioblastoma cases.

Main Methods:

• Retrospective analysis of ten Glioblastoma cases.
• Creation of two D-IMRT plans per patient: Static Jaw Technique (SJT) and Jaw Tracking Technique (JTT).
• Dosimetric comparison of PTV and OARs, including gamma analysis for portal dosimetry verification.

Main Results:

• JTT demonstrated significant improvements in dosimetric parameters for both PTV and OARs compared to SJT.
• Significant reductions in mean dose and dose volume parameters were observed for OARs like the brainstem, optic nerves, and optic chiasm with JTT.
• JTT plans achieved better gamma analysis passing rates, indicating superior dose accuracy and agreement.

Conclusions:

• The Jaw Tracking Technique (JTT) is a valuable advancement in radiotherapy planning, offering significant dosimetric advantages.
• JTT effectively reduces radiation exposure to OARs, thereby lowering the risk of acute and late toxicities.
• Implementing JTT can lead to improved tumor control and reduced risk of secondary radiogenic cancers in patients undergoing radiotherapy.