Biological In Situ Dose Painting For Image-Guided Radiation Therapy Using Drug-Loaded Implantable Devices (BIS-IGRT)

Implantable devices routinely used for increasing spatial accuracy in modern image-guided radiation treatments (IGRT), such as fiducials or brachytherapy spacers, encompass the potential for in situ release of biologically active drugs, providing an opportunity to enhance the therapeutic ratio.We model this new approach for two types of treatment. Drug distributions from three-dimensional arrangements of drug eluters versus eluter size and drug prop- erties were tabulated. Four radiosensitizer-loaded fiducials provide adequate radiosensitization for 4-cm-diame- ter lung tumors, thus potentially boosting biologically equivalent doses in centrally located stereotactic body treated lesions. Similarly, multiple drug-loaded spacers provide prostate brachytherapy with flexible shaping of ‘‘biologi- cally equivalent doses’’ to fit requirements difficult tomeet by using radiation alone, e.g., boosting a high-risk region juxtaposed to the urethra while respecting normal tissue tolerance of both the urethra and the rectum. Drug loading of implantable devices routinely used in IGRT provides new opportunities for therapy modulation via biological in situ dose painting.

© 2009 Northeastern University · 360 Huntington Ave., Boston, Massachusetts 02115 · 617.373.2000 · TTY 617.373.3768