Kiana Kelly

Cryosurgery is a surgical technique that employs freezing to destroy target tumor tissue. While the main objective during a cryosurgical procedure is to ensure tissue destruction within the cryolesion, the greatest challenge is how to spare the surrounding healthy tissues from cryoablation. In this work, a historical review of the field of cryosurgery is presented followed by a theoretical study where a mathematical model is developed for cryosurgery on a basal cell carcinoma using liquid nitrogen spray. The model takes into consideration the anatomic structure of skin tissue and the irregular geometry of BCC. In particular, a methodology for quantitatively determining the extent of the intracellular ice formation zone based on the tissue temperature and cooling rate is proposed, which can directly relate to the necrosis of the cancer cells after cryosurgery. The model is then used to analyze formation of the IIF zone during cryosurgery on a BCC and quantification is provided for the volume of the final IIF zone. A parametric study is also carried out to investigate the effect of various protocol parameters on the final IIF zone. The results should be useful for dermatologists for pre-treatment surgery planning.

Background and Objective: Due to the significant risk profile associated with traditional ablative resurfacing, a safer and less invasive treatment approach known as fractional deep dermal ablation was recently developed. We report the results of the first clinical investigation of this modality for treatment of photo- damaged skin. Study Design/Materials and Methods: Twenty-four subjects received treatments on the inner forearm with a prototype fractional CO 2 laser device at settings of 5-40 mJ/MTZ and 400 MTZ/cm 2. Clinical and histological effects were assessed by study investigators 1 week, 1 month, and 3 months following treatment. Thirty subjects were then enrolled in a multi-center study for treatment of photo- damage using the same device. Subjects received 1-2 treatments on the face and neck, with energies ranging from 10 to 40 mJ/MTZ and densities ranging from 400 to 1,200 MTZ/cm 2. Study investigators assessed severity of post-treatment responses during follow-up visits 48 hours, 1 week, 1 month, and 3 months following treatment. Using a standard quartile improvement scale, subjects and investigators assessed improvement in rhytides, pigmentation, texture, laxity and overall appearance 1 and 3 months post-treatment. Results: Clinical and histologic results demonstrated that fractional delivery of a 10,600 nm CO 2 laser source offers an improved safety profile with respect to traditional ablative resurfacing, while still effectively resurfacing epidermal and dermal tissue. Forearm and facial treatments were well-tolerated with no serious adverse events observed. Eighty-three percent of subjects exhibited moderate or better overall improvement, according to study investigator quartile scoring. Conclusions: FDDA™ treatment is a safe and promising new approach for resurfacing of epidermal and deep dermal tissue targets. Lasers Surg © 2009 Wiley-Liss, Inc.

Background and Objective: During laser therapy of port wine stain birthmarks, regions of perfusionmay persist. We hypothesize that such regions are not readily observable even when laser surgery is performed by highly experienced clinicians. The objective of this study was to use objective feedback to assess the acute vascular response to laser therapy. Study Design/Materials and Methods: A clinic-friendly laser speckle imaging instrument was developed to provide the clinician with real-time images of blood flow during laser therapy. Images were acquired from patients undergoing laser therapy of PWS birthmarks at Scripps Clinic and the Beckman Laser Institute and Medical Clinic. Blood flow maps were extracted from the acquired imaging data. Histogram-based analysis was applied in grading the degree of heterogeneity present in the blood flow maps after laser therapy. Results: Collectively, two types of patient responses were observed in response to laser exposure: an immediate increase in perfusion within minutes after laser therapy; and an overall decrease in blood perfusion ∼1 hour after laser therapy, with distinct regions of persistent perfusion apparent in the majority of post-treatment blood-flow images. A comparison of blood flow in PWS and adjacent normal skin demonstrated that PWS blood flow can be greater than, or sometimes equivalent to, that of normal skin. Conclusion: In general, a decrease in skin perfusion is observed during pulsed laser therapy of PWS birthmarks. However, a heterogeneous perfusion map was frequently observed. These regions of persistent perfusion may be due to incomplete photocoagulation of the targeted vessels. We hypothesize that immediate retreatment of these regions identified with LSI, will result in enhanced removal of the PWS vasculature. © 2009 Wiley-Liss, Inc.