Lasers in Surgery and Medicine最新文献

Objectives: To study the healing response of rat Achilles tendon when lacerated or treated with intense therapeutic ultrasound (ITU) via utilization of multiphoton microscopy (MPM) imaging and histology.

Materials and methods: The right Achilles tendon of each Sprague Dawley rat within a cohort was partially lacerated. 1 to 2 days post-surgery, each rat received ITU treatment of the Achilles tendon on either the right or left leg. Rats were euthanized in groups at 1, 3, 7, 14, or 28 days posttreatment and their tendons were explanted, formalin fixed, paraffin embedded, sectioned, and placed on slides for imaging. Slides from each time point were imaged using a laboratory built MPM with a 780 nm Ti:Sapphire laser. The resulting second harmonic generation (SHG) and two-photon excited fluorescence (2PEF) signals were captured, assessed, and compared to brightfield microscopy images of the same section subsequently stained with hematoxylin and eosin.

Results: At early timepoints, 2PEF images show the presence of red blood cells, infiltration of inflammatory cells and formation of a fibrin clot at laceration sites, and attraction of fibroblasts to ITU coagula. SHG images indicate an absence of organized collagen in both types of lesions. At later timepoints, new organized collagen can be seen at the laceration sites, and the concentration of inflammatory cells has noticeably decreased. Automated detection of red blood cells and infiltrative cells, as well as analysis of SHG signal intensity and homogeneity was performed at laceration locations. Results show that all quantities except SHG signal intensity approach normal values by day 28. Thus, combined analysis of 2PEF and SHG images elucidates tendon healing processes that align with and complement histological findings.

Conclusion: These results indicate that multiphoton imaging can effectively visualize the healing response to mechanical (laceration) and thermal (ITU) injury, including the organization of new collagen which is more difficult to visualize with histology.

Objective: Physical treatment modalities, such as ablative fractional laser (AFL), electrocautery, and cryotherapy, are extensively used in the field of dermatology. This study aimed to characterize the short-term innate and adaptive immune responses induced by AFL compared with heat- and cold-based procedures.

Materials and methods: Innate (CD11b⁺Ly6G⁺ neutrophils) and adaptive (CD8⁺CD3⁺ T cells) immune cell infiltration and histopathological changes were examined in murine skin on Days 1 and 7, following AFL, monopolar-electrocautery (RF), thermocautery, and cryotherapy. Interventions were standardized to reach the reticular dermis. Clinical skin reactions were photo-documented daily. As a comparator, the adaptive immune response was examined in murine basal cell carcinomas (BCC) on Day 7 after AFL exposure.

Results: Baseline histopathology confirmed immediate deep dermal tissue impact by all procedures. Immune cell dynamics varied across treatments throughout the progression of clinical and histopathological responses. On Day 1, AFL and heat-based procedures triggered an innate immune response, characterized by CD11b⁺Ly6G⁺ neutrophil cell infiltration that correlated with histopathological findings and immediate onset of clinical skin reactions. In addition, heat-based procedures led to an increase in overall dermal CD45⁺ cells (Day 1), which continued to rise for AFL and RF-electrocautery at Day 7 posttreatment. On the contrary, cryotherapy did not induce immediate (Day 1) innate immune responses, but instead a delayed increase in neutrophil and CD45⁺ cell infiltration (Day 7), which coincided with the late onset of clinical reaction. CD3⁺ T cells and CD8⁺CD3⁺ T cells demonstrated a similar pattern, with an increase observed for heat-based procedures on Day 1 and a delayed increase for cryotherapy on Day 7. Distinctive for AFL-treated skin, the level of dermal CD3⁺ T cells increased over time, significant by Day 7, and AFL-treated mouse BCCs responded with increased CD8⁺ T cell infiltration at Day 7 posttreatment.

Conclusion: Heat- and cold-based procedures developed distinct cutaneous immune responses, with cryotherapy resulting in a delayed response compared to immediate immune responses from heat-based procedures. The substantial T cell response induced by AFL in the skin and BCC tumors indicates a potential for AFL as an adjuvant in immunotherapeutic treatments of keratinocyte cancers.

Objectives: With over 184,000 new cases and more than 99,000 deaths per year, malignancies of the larynx are a global health problem. Currently, a dedicated screening method enabling a direct onsite diagnosis is missing. This can lead to delayed diagnosis and worse outcomes of the patients. An endoscopic optical method enabling a direct distinction between healthy tissue, dysplastic tissue and cancerous tissue would be an ideal tool for the detection of tumors of the upper aerodigestive tract (UADT). Healthy and tumor cells differ significantly in their metabolic state due to the different metabolic pathways they use (more oxidative phosphorylation in healthy cells, more glycolysis in tumor cells). Optical metabolic imaging (OMI) measuring relative intracellular concentration of NAD(P)H and FAD redox pairs could be a promising approach for early tumor detection and differentiation of suspicious mucosal lesions.

Methods: In this study, a specially designed endoscopic two-beam two-photon fluorescence lifetime imaging (FLIM) system was used to perform two-photon two-beam FLIM of NAD(P)H and FAD to image the metabolic state in different tissue samples of the UADT. FLIM data sets of 27 tissue samples from 16 patients were recorded directly after surgery ex vivo in a special tissue culture medium at 37°C on a dedicated microscope using multiphoton excitation.

Results: Based on the FLIM measurements of NAD(P)H and FAD, six of the most common indices for the characterization of the cells' metabolism were calculated. Three of them, the ratio of the exponential coefficients (amplitudes) of the short and long lifetime components both for NAD(P)H and FAD (NAD(P)H a1/a2 ratio and FAD a1/a2 ratio) and the fluorescence lifetime redox ratio (FLIRR) enabled differentiation between healthy tissue, benign lesions, dysplastic tissue, and cancer tissue with statistical significance.

Conclusions: We showed by measurements on freshly collected tissue samples that mucosal lesions of the UADT can be differentiated using our newly designed endoscopic FLIM device. In vivo measurements in healthy volunteers were also possible. By means of this technology, differentiation of cancerous, pre-cancerous, and healthy tissue in the UADT by OMI could be possible. Of six indices used to characterize cell metabolism we calculated, the FLIRR showed the most significant differences between tissue types.

Introduction: The 595-nm wavelength pulsed dye laser (PDL) is well-established in the treatment of vascular lesions. In June 2023, it received FDA clearance for the treatment of port-wine birthmarks (PWB) and infantile hemangiomas (IH) in the pediatric population.

Objective: Review the evidence regarding the efficacy, safety, and implications of using PDL for management of pediatric PWB and IH.

Methods: A systematic literature search was performed to identify peer-reviewed articles and clinical trials published between July 2002 and December 2022 in which PDL was used to treat pediatric PWB and IH.

Results: After application of criteria, 33 journal articles with 7725 total patients were included. Only 16 (0.8%) of the 2,033 patients with PWB and 11 (0.2%) of the 5692 patients with hemangioma reported permanent adverse effects including scarring, keloids, or permanent pigmentation change, and none reported blindness or other serious injury. Good, excellent, or complete clearance after PDL-on average or in greater than 50% of patients-was reported in 17 of 19 studies (89%) that reported these measures for PWB, and seven of the seven studies (100%) for IH.

Conclusion: The 595-nm PDL is an excellent treatment option for early intervention in pediatric patients with PWB or IH.

Background: Ablative fractional CO₂ laser (10,600 nm) treatment creates an array of microscopic treatment zones composed of an ablation zone (AZ) surrounded by a denatured coagulation zone (CZ). The CZ is believed to play a functional role in skin tightening, posttreatment inflammation, and laser-assisted drug delivery. This study investigates the viability of enzymatic post-processing to remove the CZ without affecting the surrounding tissue.

Methods: Ex vivo skin samples were treated with either control, papain, urea, or papain-urea solutions before being covered with occlusive dressing and incubated at 37°C for 1 h. Tissue viability as well as AZ and CZ geometries were assessed histologically.

Results: Treatment with all three experimental solutions resulted in a decrease in CZ. The largest average reduction in CZ area was observed in the papain-urea group (44%, p < 0.001), followed by the papain (14%, p < 0.001) and urea (11%, p < 0.001) only groups. Only the papain-urea group showed a significant increase in AZ (14%) and changes in lesion geometry.

Conclusion: This exploratory study of enzymatic post-processing with papain-urea highlighted the potential of selectively removing the CZ after treatment with ablative fractional laser therapy. If results can be translated to in vivo studies, these findings could expand the use of high-fluence CO₂ laser therapy with functional implications for lowering posttreatment recovery time, providing clinicians more control over skin tightening, and enabling a broader range of laser-assisted drug delivery.

Objectives: One of the widely used optical biopsy methods for monitoring cellular and tissue metabolism is time-resolved fluorescence. The use of this method in optical liver biopsy has a high potential for studying the shift in energy-type production from oxidative phosphorylation to glycolysis and changes in the antioxidant defense of malignant cells. On the other hand, machine learning methods have proven to be an excellent solution to classification problems in medical practice, including biomedical optics. We aim to combine time-resolved fluorescence measurements and machine learning to automate the division of liver parenchyma and tumors (primary malignant, metastases and benign tumors) into classes.

Materials and methods: An optical biopsy was performed using a developed setup with a fine-needle optical probe in clinical conditions under ultrasound control. Fluorescence decays were recorded in a conditionally healthy liver and lesions during percutaneous needle biopsy. The labeled data set was created on the basis of the recorded fluorescence results and the histopathological classification of the biopsies obtained. Several machine learning methods were trained using different separation strategies of the training test set, and their respective accuracy was compared.

Results: Our results show that each of the tumor types had its own characteristic metabolic shifts recorded by the time-resolved fluorescence spectroscopy. The application of machine learning demonstrates a reliable separation of the liver and all tumor types into cancer and noncancer classes with sensitivity, specificity and corresponding accuracy greater than 0.91, 0.79 and 0.90, using the random forest method. We also show that our method is capable of giving a preliminary diagnosis of the type of liver tumor (primary malignant, metastases and benign tumors) with a sensitivity, specificity and accuracy of at least 0.80, 0.95 and 0.90.

Conclusions: These promising results highlight its potential as a key tool in the future development of diagnostic and therapeutic strategies for liver cancers. Lasers Surg. Med. 00:00-00, 2024. 2024 Wiley Periodicals LLC.

Background: Photodynamic therapy (PDT) induced lipid peroxidation reaction can lead to necrosis and apoptosis of extrahepatic cholangiocarcinoma (ECC) cells, reducing the tumor load. However, the depth of action of PDT is shallow, and its therapy efficacy is weak, making it difficult to achieve eradication even with multiple treatments.

Objectives: This study aims to investigate the mechanism and main pathways of ferroptosis in cholangiocarcinoma under Hematoporphyrin-mediated photodynamic therapy, and to compare the effects of different ferroptosis inducers on photodynamic therapy-induced ferroptosis in cholangiocarcinoma. To provide an experimental basis for selecting appropriate ferroptosis-inducing agents and synergizing with photodynamic therapy during the clinical perioperative period.

Methods: The Cell Counting Kit-8 (CCK-8) was used to examine the cytotoxicity of cholangiocarcinoma cells following PDT. Flow cytometry was used to detect apoptotic cell percentage and cell cycle changes to assess the enhanced photodynamic production of reactive oxygen species (ROS) by different ferroptosis inducers, confocal imaging was used to de-assay ROS content. Western blot analysis was employed to detect the expression of GPX4 、FSP1、ASCL4 and SLC7A11. Furthermore, a fluorescence spectrophotometric assay was used to quantify the alterations in lipid peroxides (MDA, LPO, GSH, and Fe²⁺).

Results: The combination of PDT with Lenvatinib or Erastin resulted in increased ROS levels, and decreased GSH content, tumor cells were inhibited in the G2 phase, and the proportion of apoptotic cells increased. Additionally, GPX4, FSP1, and SLC7A11 protein expression decreased, whereas ASCL4 increased This was accompanied by heightened levels of Fe²⁺, LPO, and MDA. Induction of the ferroptosis pathway was observed to enhance the therapeutic efficacy of PDT.

Conclusion: Our findings suggest that Erastin or Lenvatinib can enhance the induction of ferroptosis in cholangiocarcinoma cells by photodynamic therapy by increasing intracellular ROS and inhibiting intracellular antioxidant pathways.

Background and objectives: Commonly adopted in cosmetic dermatology, nonablative radiofrequency (RF) devices convert high-frequency electromagnetic energy into thermal energy to induce a wound-healing response in skin tissue. However, differences in the electrical properties of different skin layers raise questions about the impact of different RF frequencies and target temperatures on treatment effectiveness. This paper presents a finite element analysis (FEA)-based computational study aimed at simulating and optimizing the effects of a proportional integral derivative (PID)-controlled RF cosmetic devices under different combinations of these two parameters during treatment.

Study design/materials and methods: A 3D physical model for the application of a nonablative RF device was constructed using COMSOL, which included the human tissue and RF electrodes, electromagnetic and thermal boundary conditions, as well as the PID controller. FEA was performed for each of the twelve models with parameter combinations of three RF frequencies (0.1, 0.5, and 1 MHz) and three PID-controlled target temperatures (60°C, 65°C, and 70°C) plus one group without PID control. Treatment effectiveness was quantitatively assessed using the integration of tissue thermal damage fraction, i.e., thermal damage volume.

Results: In the earlier stage of heating (0-10 s), higher RF frequency resulted in a larger thermal damage volume. At 10 s, among models with a temperature target of 70°C, there is a 6.04% difference between the thermal damage volume at RF frequencies of 1.0 and 0.1 MHz. In the later stage of heating(11-80 s), the impact of RF frequency decreases. The difference in thermal damage volume caused by higher temperature targets is more significant, at 80 s, among models with an RF frequency of 1.0 MHz, the 70°C model produces 1.15 and 1.36 times more tissue thermal damage than the 65°C and 60°C models.

Conclusion: PID controller has ensured treatment safety and uniformity, in exchange for some efficiency. Among 12 parameter combinations, the one with a temperature of 70°C and RF frequency of 1.0 MHz achieved the highest thermal damage volume, which could potentially result in the best esthetic effect. Considering users' different susceptibility to heat, engineers or physicians can select better temperature targets and RF frequencies to bring the desired cosmetic results based on thermal damage volume curves from this study.

Background: Evaluate imaging photoplethysmography (iPPG) as a novel noninvasive technique to assess flap perfusion in head and neck free flap reconstructive (FFR) surgeries.

Methods: Intraoperative iPPG was performed in 17 patients undergoing FFR surgery. Imaging consisted of a 30-s video from which perfusion maps were extracted, providing detailed information about blood flow and pulsatility in the flap microvasculature. During each procedure, iPPG acquisitions were acquired representing distinct perfusion conditions of the flap (fully perfused/ischemic/reperfused). When possible, postoperative measurements were performed to assess flap recovery during the critical time period (3 days) and long-term follow-up (30 days).

Results: Perfusion maps, displaying iPPG amplitude and delay times, correlated strongly (p < 0.001) with the perfusion status of the tissue. One case of postoperative thrombosis, leading to flap failure, was identified with iPPG. After surgical revision in this case, flap perfusion was restored and confirmed by iPPG. Postoperative follow-up imaging allowed for objective visualization of flap recovery short term (3 days) and up to 30 days after the surgical procedure.

Conclusions: This study shows that iPPG is suitable for objective and noninvasive assessment of flap perfusion in head and neck FFR surgery. In addition, postoperative monitoring shows potential for assessing flap perfusion in patients with increased risk of postoperative complications.