Abstract Background and Objectives Laser smoke is a biohazard that contains potentially dangerous toxic and biological components. In laser hair removal (LHR), practitioners undergo prolonged exposure as this procedure is widely used without protective measures. Little is known about the effect of smoke evacuators on ultrafine particle concentrations during LHR. This study aims to assess the effect of different laser devices and different smoke evacuators on the ultrafine particle concentrations in the room during LHR. Study Design/Materials and Methods In a prospective observational study, we included patients with skin phototypes 2–4 for 755 nm Alexandrite LHR at two study sites, receiving treatment in axillae and pubic areas. Ultrafine particle concentrations were measured during LHR for two different alexandrite lasers, with and without an external smoke evacuator. Moreover, we assessed a device for LHR with a smoke evacuator integrated into the handpiece. Primary outcomes were the concentration of ultrafine particles (0.2–0.3 µm) per m 3 at 1 min after initiation of treatment and maximum concentrations. Results A total of 15 patients were recruited for routine LHR. Without a smoke evacuator, already at 1 minute after treatment onset, ultrafine particle concentrations rapidly increased. Both external and integrated smoke evacuators were highly effective with a 3.7–7‐fold decrease in maximal particle count. Similarly, maximal particle concentrations remained low with both smoke evacuators. At both study sites, particle concentrations decreased slowly (8 min for 50% reduction) when treatment stopped. Conclusion LHR procedures generated an increase of ultrafine particles. Both the external and integrated smoke evacuators are highly effective in controlling ultrafine particle concentrations during LHR. Once particle concentrations are elevated and the process had been completed, clearance of ultrafine particles is rather slow.
Bladder cancer was the 10th most prevalent cancer worldwide in 2020. Currently, the gold standard for diagnosing bladder cancer is a cystoscopy followed by a transurethral resection of the bladder tumour. The tumour invasion and grade are needed to determine the treatment plan. However, a transurethral resection is an invasive procedure, needs planning and has complication risks. Therefore, finding an alternative option to determine tumour invasion and grade is necessary. That would also enable other treatment options for bladder cancer such as laser fulguration, chemo-resection and active surveillance. Optical Coherence Tomography (OCT) has the potential to aid in the diagnosis of bladder cancer
Abstract Aim In this systematic review we aimed to identify all quantitative fluorescent parameters of intraoperative fluorescence angiography (IFA) during gastrointestinal surgery to pave way for a threshold that could predict anastomotic leakage (AL). Background &Methods In the last decade quantification of IFA using indocyanine green is attempted to objectively evaluate anastomotic perfusion during gastrointestinal surgery. In this systematic review, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A literature search of PubMed and Embase was performed. Articles were included when IFA was performed to assess gastrointestinal perfusion in both animal and human and analysed the fluorescence signal using quantitative fluorescent parameters. A fluorescent parameter was defined as ‘quantitative’ when a diagnostic numeral threshold for AL could potentially be produced. Results Some 1317 articles were identified, of which 23 were included in this review. Eight applied IFA during upper and fifteen during lower gastrointestinal surgery. The quantitative fluorescent parameters were divided into four categories: (1) time to fluorescence (n=19), (2) contrast-to-background ratio (n=3), (3) pixel intensity (n=3), and (4) numeral classification score (n=2). The first category was subdivided into (a) time to fluorescent enhancement (n=7) and (b) fluorescent-time curves (n=12). Thirteen studies correlated the fluorescent parameters to the occurrence of AL. Cut-off values for AL were derived for time to fluorescent enhancement (speed in gastric conduit wall) and derivatives of the fluorescent-time curves (Fmax, T1/2, TR, and slope). Conclusion Of the four categories, time to fluorescent enhancement seems the most promising quantitative parameter for clinical usage, as development of a cut-off value is possible on a large scale in the near future and no software is required. Future research might want to focus on fluorescent-time curves, as many different parameters can be derived and the fluorescence intensity can be bypassed. However, consensus on study set-up, and calibration of the different fluorescent imaging systems and software programs is mandatory to allow future data aggregation.
This study investigates the feasibility of in vivo quantitative optical coherence tomography (OCT) of human brain tissue during glioma resection surgery in six patients. High-resolution detection of glioma tissue may allow precise and thorough tumor resection while preserving functional brain areas, and improving overall survival. In this study, in vivo 3D OCT datasets were collected during standard surgical procedure, before and after partial resection of the tumor, both from glioma tissue and normal parenchyma. Subsequently, the attenuation coefficient was extracted from the OCT datasets using an automated and validated algorithm. The cortical measurements yield a mean attenuation coefficient of 3.8 ± 1.2 mm
Extracellular vesicles (EVs) are nanoparticles secreted from cells into bodily fluids. EVs are potential biomarkers for diseases such as thrombosis or cancer. However, the small size and low refractive index of EVs complicates their detection. A flow cytometer is suited for EV characterisation, but typically lacks scatter sensitivity on one or both scatter detectors for derivation of both particle size and refractive index. Here, we aim to improve the FACSCanto (Becton Dickinson) forward scatter detector for the detection of 100 nm EVs, which requires an improvement in SNR of 107-fold based on Mie theory. This was achieved through replacement of the 20 mW laser by an 200 mW laser, replacement of the photodiode detector with a photomultiplier tube and a confocalized optical geometry. Using a prototype optical setup, we obtained an improvement in SNR which was 1,11·104 – fold better than the standard design. However, the optics was suboptimal and far from diffraction-limited. Zemax simulations led to a nearly diffraction limited optical design which is expected to yield another 200-fold improvement. Taken together these changes will improve the SNR 2.2·106-fold and thus improve the detection limit of the FACSCanto to 130 nm EVs.
We present a bi-modal bench-top system combining OCT with broadband, single-fiber reflectance spectroscopy. This combination aims to address the limited molecular sensitivity of standard OCT imaging in order to obtain co-registered morphological and molecular information. We present various technical innovations for this work, including an all-reflective scanner head with adaptive optic components for focus scanning and reduction of field curvature. Furthermore, we demonstrate the use of specialty fiber components to obtain multiple illumination schemes for the spectroscopic channel and enhance the spatially resolved reconstruction of optical properties.
Abstract Intralesional corticosteroid injections are a first-line treatment for keloids; yet clinical treatment results are highly variable and often suboptimal. Variation in triamcinolone acetonide (TAC) biodistribution may be an important reason for the variable effects of TAC treatment in keloids. In this exploratory study we investigated the biodistribution of TAC in keloids and normal skin using different drug delivery techniques. Fluorescent-labeled TAC suspension was administered into keloids and normal skin with a hypodermic needle and an electronic pneumatic jet injector. TAC biodistribution was represented by the fluorescent TAC volume and 3D biodistribution shape of TAC, using a 3D-Fluorescence-Imaging Cryomicrotome System. Twenty-one keloid and nine normal skin samples were analyzed. With needle injections, the mean fluorescent TAC volumes were 990 µl ± 479 in keloids and 872 µl ± 227 in normal skin. With the jet injector, the mean fluorescent TAC volumes were 401 µl ± 252 in keloids and 249 µl ± 67 in normal skin. 3D biodistribution shapes of TAC were highly variable in keloids and normal skin. In conclusion, TAC biodistribution in keloids is highly variable for both needle and jet injection. This may partly explain the variable treatment effects of intralesional TAC in keloids. Future research is needed to confirm this preliminary finding and to optimize drug delivery in keloids.
