Dosie™ validated in I-PDT clinical trial to treat Malignant Central Airway Obstruction
Cancers, May 2023 (Special Issue: Remote-Controlled Therapeutics for Cancer Therapy and Imaging) – Currently, there are no effective treatments for patients suffering from cancers that compress or constrict the bronchus resulting in troubled breathing. To allow for normal breathing and delay disease progression, the effects of these cancerous tumors must be quickly alleviated. So far, in our clinical trial (NCT03735095), research demonstrates that interstitial photodynamic therapy (I-PDT) combined with innovative image-based computer optimization methods may offer a safe and effective treatment option for patients suffering from Malignant Central Airway Obstruction (MCAO). In this study, we introduced and validated novel image-based computer optimization methods, leveraging a novel rate-based light dose metric to guide light administration in I-PDT to treat extrinsic MCAO. By employing finite element method solvers from Dosie™ and Comsol Multiphysics® for light propagation simulations, we optimized the delivered irradiance and fluence while keeping the irradiance and the fluence at the surrounding critical structures (e.g., major blood vessels) below safety thresholds, which our academic partners (Dr. Shafirstein's research team) from Roswell Park Comprehensive Cancer Center believe are the crucial factors in achieving an effective PDT response.
In this publication, we presented Dosie's novel Domination sub-maps method to improve the planning of the delivery of effective rate-based light doses. When applying Dosie's Domination sub-maps method to optimize cylindrical diffuser fibers' power and treatment time, we achieved a 15% increase in the tumor volume that received the effective rate-based light dose. In the paper, we presented a detailed description of the treatment planning procedure using either Doise or Comsol for MCAO I-PDT. Additionally, we showed that Dosie agrees with Comsol when calculating the irradiance and the rate-based light dose distribution throughout the tumor geometries. Applying supported in Dosie simple algebraic expressions and customized operators over irradiance maps and fluence maps significantly reduce overall optimization time as there is no need to re-run time-consuming FEM calculations when the irradiance maps need to be updated during optimization. Finally, this methodology is relatively general and can be potentially adopted for other indications and photosensitizers in I-PDT treatment planning, assuming that the appropriate rate-based light doses are provided.
Figure: A fragment of the patient’s 3D mesh with tumor and surrounding critical structures that shows locations where cylindrical diffusing fibers (CDFs) were inserted.
Figure: Dosie screenshots of Domination Sup-maps over the tumor of a typical patient with locally advanced MCAO tumor for four CDFs. Non-yellow colors represent regions where a particular CDF dominates the other three CDFs.
