Image-guided total marrow and total lymphatic irradiation using helical tomotherapy

Area of Science:

• Radiation Oncology
• Medical Physics
• Cancer Therapy

Background:

• Total body irradiation (TBI) is a standard radiotherapy technique.
• Conventional TBI delivers uniform doses, potentially causing significant toxicity to normal tissues.
• There is a need for advanced techniques to spare normal tissues while escalating radiation doses.

Purpose of the Study:

• To develop intensity-modulated radiotherapy techniques for total body irradiation (TBI).
• To enable dose escalation and normal tissue sparing in total marrow irradiation (TMI), total lymphatic irradiation, and total bone marrow plus lymphatic irradiation.
• To utilize helical tomotherapy for precise radiation delivery.

Main Methods:

• Utilized helical tomotherapy for intensity-modulated radiotherapy delivery.
• Defined treatment targets including bone marrow, lymphatic areas, and sanctuary sites.
• Identified and prioritized organs for sparing, including lungs, kidneys, and gastrointestinal tract.

Main Results:

• Helical tomotherapy allowed for significant sparing of visceral organs compared to conventional TBI.
• In TMI patients, organs at risk received a median dose 51% lower than with TBI.
• Prioritizing organ avoidance further enhanced normal tissue sparing.

Conclusions:

• Helical tomotherapy facilitates normal tissue sparing and dose escalation in TBI.
• Reduced doses to organs at risk are expected to decrease the incidence and severity of late radiation effects.
• This technique holds promise for improving outcomes in patients undergoing TBI.