A Monte Carlo simulation study on the evaluation of radiation protection properties of spectacle lens materials.

The eye lens has been known a radiosensitive tissue. Radiation exposure can cause opacities, cataracts and vision loss. The sensitivity of the eyes to ionizing radiation has attracted attention in the last decade. ICRP announced that equivalent dose limit of eye lens has dropped in recent years. Therefore, spectacle lens selection is becoming increasingly important. In this study, the radiation protection properties of spectacle lens (CR-39, Polycarbonate and Trivex) materials were investigated using the MCNP-6.2 Monte Carlo code and SRIM software. The suitability of the results obtained with MCNP-6.2 Monte Carlo code was provided by comparing the theoretical results obtained from the WinXCOM program. The results showed that the CR-39 spectacle lens had minimum half-value layer, tenth value layer and mean free path values. In addition to the photon protection properties of spectacle lens materials, proton (H1) and alpha (He+2) radiation protection properties were also investigated. Mass stopping power and projected range (PR) values for proton and alpha particles were calculated using SRIM code in the energy range of 0.01-10 MeV. As a result of the research, it was seen that the CR-39 lens had minimum PR values.

Phenotyping for percutaneous coronary intervention and long-term recurrent weighted outcomes.

INTRODUCTION: Percutaneous coronary interventions (PCI) are often performed in multimorbid patients with heterogeneous characteristics and variable clinical outcomes. We aimed to identify distinct clinical phenotypes utilizing machine learning and explore their relationship with long-term recurrent and weighted outcomes. METHODS: This prospective observational cohort study enrolled all-comer PCI patients in 2020-2021. Multiple imputation k-means clustering was utilized to detect specific phenotypes. The study endpoints were patient-oriented and device oriented composite endpoints (POCE, DOCE), its individual components, and major bleeding. We applied semiparametric regression models for recurrent and weighted endpoints. RESULTS: The study included a total of 643 patients. We unveiled three phenotype clusters: 1) inflammatory (n = 44, with high white blood cell counts, high values of C-reactive protein (CRP) and neutrophil-to-lymphocyte ratio), 2) high erythrocyte sedimentation rate (ESR) (n = 204), and 3) non-inflammatory (n = 395). For ACS-only population, we four distinct phenotypes (high-CRP, high-ESR, high aspartate-aminotransferase, and normal). For all-comer PCI patients, identified phenotypes had a higher risk of POCE (mean ratio (MR) 1.42 (95% confidence interval (CI) 1.11-1.81) and MR 2.01 (95% CI 1.58-2.56), respectively), DOCE (MR 1.61 (95% CI 1.20-2.16), MR 2.60 (95%CI 1.94-3.48), respectively), and stroke (hazard ratio (HR) 2.86 (95% CI 1.10-7.4), 6.83 (95% CI 2.01-23.2)). Similarly, high-ESR and high-CRP phenotypes of ACS patients were significantly associated with the development of clinical composite outcomes. CONCLUSION: Machine learning unveiled three distinct phenotype clusters in patients after PCI that were linked with the risk of recurrent and weighted clinical endpoints. German Clinical Trial Registry number: DRKS00020892.

Pharyngocutaneous fistula after total laryngectomy: emphasis on lymph node metastases as a new predisposing factor.

OBJECTIVE: We investigated patient-related and local risk factors for pharyngocutaneous fistula developing after total laryngectomy. DESIGN: Retrospective clinical study. SETTING: Tertiary medical centre. METHOD: The study included 255 patients who underwent total laryngectomy and concurrent neck dissection between July 2001 and February 2006 for laryngeal cancer. MAIN OUTCOME MEASURES: The association of fistula and patient-related (age, sex, hemoglobin and albumin levels, diabetes mellitus, chronic obstructive pulmonary disease, chronic congestive heart disease, hypertension) and local risk factors (T stage of the tumour and localization, previous radiotherapy, preoperative tracheostomy, lymph node metastases, surgical margin) was analyzed using the chi-square and independent-sample t-tests. RESULTS: Pharyngocutaneous fistulae were found in 18.4% of the patients. Lymph node metastases, chronic congestive heart disease, and postoperative hemoglobin and albumin levels lower than 10.84 +/- 1.2 g/dL and 3.06 +/- 0.5 g/dL, respectively, were found to be statistically significant risk factors in fistula formation. The logistic regression model was carried out on these risk factors. CONCLUSION: Pharyngocutaneous fistula remains the most frequent complication of total laryngectomy despite improved preoperative assessment and postoperative care. Lymph node metastases emerged for the first time as a risk factor for fistula formation. Our experience confirmed that meticulous postoperative care should be paid to the patients who have contributing risk factors and lymph node metastases.

[Pharyngocutaneous fistula after total laryngectomy: incidence and analysis of risk factors]. / Total larenjektomi sonrasinda farengokutanöz fistül sikligi ve risk faktörlerinin analizi.

OBJECTIVES: We evaluated the incidence and predisposing risk factors of pharyngocutaneous fistulas that develop after total laryngectomy. PATIENTS AND METHODS: The records of 210 patients (19 females, 191 males; mean age 60+/-9 years; range 39 to 77 years) who underwent total laryngectomy were retrospectively reviewed. Thirteen predisposing risk factors were evaluated (age, sex, pre-and postoperative anemia and hypoalbuminemia, diabetes mellitus, coronary artery disease, chronic obstructive pulmonary disease, hypertension, preoperative tracheotomy, tumor stage and localization). RESULTS: Pharyngocutaneous fistulas were found in 41 patients (19.5%). The mean duration for fistula formation was 7.7 days (range 2 to 16 days). Coronary artery disease (p=0.00), postoperative hemoglobin (p=0.000) and albumin (p<0.005) levels lower than 10.7+/-1.2 g/dl and 3.0+/-0.5 g/dl, respectively, were found to be significant risk factors for fistula formation. CONCLUSION: Fistula formation is the most frequent complication in laryngectomy patients. To prevent fistula formation, special attention should be paid to surgical technique and postoperative care especially in patients who have coronary artery disease, anemia, and hypoalbuminemia.

[Castleman's disease of the cervical region: a case report]. / Servikal bölgede Castleman hastaligi: olgu sunumu.

Castleman's disease is a rare disorder characterized by massive proliferation of the lymphoid tissue due to an unknown cause. Two clinical types (localized, multicentric) have been described with three histological variants (hyaline-vascular, plasma cell, and mixed type). A 47-year-old female patient was referred to our department because of a swelling in the posterior cervical region. Fine-needle aspiration biopsy was suggestive of lymphoma. Total excision of the mass was performed under general anesthesia with intraoperative frozen section examination. Histopathologic diagnosis was Castleman's disease of hyaline-vascular type. Castleman's disease should also be considered for suspicious masses in the neck.