Evaluating Bacterial Response in Sarcoma Management Using Fluorescence Imaging

The investigators have recently developed an innovative optical molecular imaging platform (called PRODIGI) based on high-resolution fluorescence and white-light technologies in a hand-held, real-time, high-resolution, non-invasive format. PRODIGI offers a non-contact means of obtaining instantaneous image-based measurements of diagnostically-relevant biological and molecular information of a wound and surrounding skin tissues for the first time and could have significant impact on improving conventional wound care, management, and guidance of intervention. In preliminary preclinical testing, the investigators have discovered that when wounds are illuminated by violet/blue light, endogenous collagen in the connective tissue matrix emit a characteristic green fluorescent signal, while most pathogenic bacterial species emit a unique red fluorescence signal due to the production of endogenous porphyrins. Therefore, with autofluorescence imaging, no exogenous contrast agents are needed during imaging, making this approach particularly appealing as a diagnostic imaging method for clinical use. In the context of this study, PRODIGI is used to assess wound complications in patients diagnosed with soft tissue sarcoma and treated with pre-operative radiotherapy. Both pre- and postoperative external beam radiotherapy combined with limb salvage surgery have similarly high rates of local control in the management of extremity soft tissue sarcoma. The main acute side effect associated with preoperative radiotherapy is wound healing complications. Wound care overall is a major clinical challenge and presents an enormous burden to health care worldwide. The objective of this clinical study is to determine if PRODIGI coupled with an optical tracking platform has clinical utility in identifying, quantitatively measuring and longitudinally tracking bacterial imbalance on the patient\'s intact skin surface at the location of the surgical resection site for adult patients with lower limb soft tissue sarcoma treated with preoperative intensity-modulated radiation therapy and limb salvage surgery and, further, to investigate whether this bacterial imbalance is related to radiotherapy dose and wound complications.