Dosimetric evaluation of total marrow irradiation using 2 different planning systems

Area of Science:

• Radiation Oncology
• Medical Physics
• Radiotherapy Planning

Background:

• Total marrow irradiation (TMI) is a complex radiotherapy technique requiring precise dose delivery.
• Evaluating and comparing different treatment planning systems (TPSs) is crucial for optimizing TMI quality and efficiency.
• Existing TPSs may have limitations in achieving optimal dose distribution and sparing organs at risk (OARs) during TMI.

Purpose of the Study:

• To compare the plan quality and efficiency of two TPSs: VOxel-Less Optimization (VoLO) and Eclipse.
• To assess the dosimetric outcomes, including target coverage and OAR sparing, for TMI plans generated by VoLO and Eclipse.
• To evaluate the computational time and beam-on time associated with each TPS for TMI planning.

Main Methods:

• Two TPSs, VoLO (helical dose delivery) and Eclipse (VMAT), were used to create TMI plans for an Alderson Rando phantom.
• A prescription dose of 1200cGy to cover 95% of the planning target volume (PTV) was used.
• Plans were evaluated based on PTV dose metrics, OAR doses (lungs, heart, liver, kidneys, brain, small bowel), optimization/calculation time, and beam-on time.

Main Results:

• Both TPSs generated acceptable TMI plans, but VoLO demonstrated superior OAR sparing for 5 out of 6 OARs, with reduced mean and D10 doses.
• VoLO achieved a more uniform dose distribution within the PTV and a steeper dose fall-off compared to Eclipse.
• Total computational time for VoLO (0.9 hours) was significantly faster than for Eclipse (3.8 hours), attributed to its GPU-based algorithm.

Conclusions:

• The VoLO planning system provides superior OAR sparing and more uniform dose distribution for TMI compared to Eclipse.
• VoLO's GPU-based optimization significantly reduces planning time, enhancing efficiency in TMI delivery.
• VoLO represents a promising advancement for high-quality and efficient total marrow irradiation planning.