Real-time treatment light dose guidance of Pleural PDT: an update.

The goal of this study was to develop and improve an infrared (IR) navigation system to deliver light dose uniformly during intracavitory PDT by tracking the movement of the light source and providing real-time feedback on the light fluence rate on the entire cavity surface area. In the current intrapleural PDT protocol, several detectors placed in selected locations in the pleural cavity monitor the light doses. To improve the delivery of light dose uniformity, an IR camera system is used to track the motion of the light source as well as the surface contour of the pleural cavity. Monte-Carlo simulation is used to improve the calculation algorithm for the effect of light that undergoes multiple scattering along the surface in addition to an improvement of the direct light calculation using an improved model that accounts for the anisotropy of the light from the light source.

Tri-modal confocal mosaics detect residual invasive squamous cell carcinoma in Mohs surgical excisions.

For rapid, intra-operative pathological margin assessment to guide staged cancer excisions, multimodal confocal mosaic scan image wide surgical margins (approximately 1 cm) with sub-cellular resolution and mimic the appearance of conventional hematoxylin and eosin histopathology (H&E). The goal of this work is to combine three confocal imaging modes: acridine orange fluorescence (AO) for labeling nuclei, eosin fluorescence (Eo) for labeling cytoplasm, and endogenous reflectance (R) for marking collagen and keratin. Absorption contrast is achieved by alternating the excitation wavelength: 488 nm (AO fluorescence) and 532 nm (Eo fluorescence). Superposition and false-coloring of these modes mimics H&E, enabling detection of cutaneous squamous cell carcinomas (SCC). The sum of mosaic Eo+R is false-colored pink to mimic the appearance of eosin, while the AO mosaic is false-colored purple to mimic the appearance of hematoxylin in H&E. In this study, mosaics of 10 Mohs surgical excisions containing invasive SCC, and five containing only normal tissue were subdivided for digital presentation equivalent to 4 × histology. Of the total 50 SCC and 25 normal sub-mosaics presented, two reviewers made two and three type-2 errors (false positives), respectively. Limitations to precisely mimic H&E included occasional elastin staining by AO. These results suggest that confocal mosaics may effectively guide staged SCC excisions in skin and other tissues.

Renal transplantation in systemic vasculitis: when is it safe?

BACKGROUND: There are no clear guidelines on renal transplantation in patients with antineutrophil cytoplasmic antibody (ANCA)-positive vasculitis. METHODS: We undertook a survey of transplant centres across Europe to assess whether there was consensus about how to manage transplantation in patients with vasculitis. We then identified 107 renal allograft recipients whose primary disease was systemic vasculitis and assessed their outcome post-transplant. RESULTS: All questionnaire respondents felt that vasculitis should be in remission at transplantation, 16% believed that ANCA should be negative pre-transplant and 40% felt that one should wait >12 months after remission before transplanting. Remission was defined by all as an absence of clinical symptoms of vasculitis, but three respondents (13%) also required a negative ANCA test. Overall graft survival was 70% after 10 years (95% C.I. 58-82). A total of 30 (41% of those with known ANCA status) were ANCA-positive peri-transplantation, while 15 (14%) were transplanted <1 year post-remission. Severe vasculopathy occurred more frequently in ANCA-positive recipients (odds ratio 4.4, 95% C.I. 1.1-16.8, P < 0.05), although causation cannot be determined from this study. Vasculopathy significantly reduced 10-year graft survival to 47% (P < 0.05). However, ANCA status per se was not significantly associated with graft failure. The strongest predictor of death was transplantation <1 year post-vasculitis remission on both univariate and multivariate analysis (hazard ratio 2.3, P < 0.05). CONCLUSIONS: In conclusion, circulating ANCA at transplant was associated with the development of vascular lesions in the graft but was not significantly correlated with graft survival. Most grafts were lost due to patient death, which was more likely if transplantation occurred <12 months following induction of remission of ANCA-positive vasculitis.

Three Monte Carlo programs of polarized light transport into scattering media: part I.

Propagation of light into scattering media is a complex problem that can be modeled using statistical methods such as Monte Carlo. Few Monte Carlo programs have so far included the information regarding the status of polarization of light before and after a scattering event. Different approaches have been followed and limited numerical values have been made available to the general public. In this paper, three different ways to build a Monte Carlo program for light propagation with polarization are given. Different groups have used the first two methods; the third method is original. Comparison in between Monte Carlo runs and Adding Doubling program yielded less than 1 % error.