Dosimetric comparison between jaw tracking and static jaw techniques in intensity-modulated radiotherapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Treatment

Background:

• Dynamic intensity-modulated radiotherapy (d-IMRT) is an advanced cancer treatment technique.
• Comparing different beam delivery methods is crucial for optimizing radiation therapy.
• Organs at risk (OARs) require careful sparing during treatment to minimize side effects.

Purpose of the Study:

• To compare dosimetric differences between jaw tracking technique (JTT) and static jaw technique (SJT) in d-IMRT.
• To evaluate the potential advantages of JTT over SJT in radiation therapy planning.
• To assess OAR sparing and overall dose distribution in d-IMRT.

Main Methods:

• d-IMRT plans were developed for 28 cancer patients using both JTT and SJT.
• Dosimetric parameters, including dose-volume histograms (DVHs) and OAR doses, were analyzed.
• Plans were verified using a 2D ionization chamber array and phantom.

Main Results:

• Both JTT and SJT d-IMRT plans met clinical requirements for target coverage.
• JTT significantly reduced whole-body and lung doses (V5-V40, Dmean) compared to SJT (p < 0.001).
• JTT demonstrated superior OAR sparing, reducing Dmax and Dmean doses to critical structures by up to 28.6% and 31.0%, respectively.

Conclusions:

• JTT provides comparable target dose coverage to SJT in d-IMRT.
• JTT offers significant advantages in OAR sparing compared to SJT.
• JTT is particularly beneficial for complex targets near sensitive OARs and for re-irradiation scenarios.