Purpose: This study aimed to present a novel method for estimating the effective atomic number(Zeff ) using dual-energy computed tomography (DECT) designed to improve accuracy andstreamline clinical workflows by reducing computational complexity. Methods: The proposed model leverages the DECT-derived mass attenuation coefficients without detailed compositional analysis. By incorporating additional parameters into the conventional Rutherford model, such as exponential and trigonometric functions, the model effectively capturescomplex variations in attenuation, enabling precise Zeff estimation. Model fitting was performedusing dual-energy data and evaluated using the percentage difference in error rates. Results: Compared with the Rutherford model, which recorded a maximum error rate of 0.55%, the proposed model demonstrated a significantly lower maximum error rate of 0.15%, highlightingits precision. Zeff estimates for various materials closely matched the reference values, confirmingthe improved accuracy of the model. Conclusions The proposed DECT-based model provides a practical and efficient approach to Zeff estimation, with potential applications in radiation oncology, particularly for accurate stopping power ratio calculations in proton and heavy ion therapies.

Purpose: This study aimed to present a novel method for estimating the effective atomic number(Zeff ) using dual-energy computed tomography (DECT) designed to improve accuracy andstreamline clinical workflows by reducing computational complexity. Methods: The proposed model leverages the DECT-derived mass attenuation coefficients without detailed compositional analysis. By incorporating additional parameters into the conventional Rutherford model, such as exponential and trigonometric functions, the model effectively capturescomplex variations in attenuation, enabling precise Zeff estimation. Model fitting was performedusing dual-energy data and evaluated using the percentage difference in error rates. Results: Compared with the Rutherford model, which recorded a maximum error rate of 0.55%, the proposed model demonstrated a significantly lower maximum error rate of 0.15%, highlightingits precision. Zeff estimates for various materials closely matched the reference values, confirmingthe improved accuracy of the model. Conclusions The proposed DECT-based model provides a practical and efficient approach to Zeff estimation, with potential applications in radiation oncology, particularly for accurate stopping power ratio calculations in proton and heavy ion therapies.

This study explores the development, roles, and key initiatives of the Regional Environmental Health Centers in Korea, detailing their evolution through four distinct phases and their impact on environmental health policy and local governance. It chronicles the establishment and transformation of these centers from their inception in May 2007, through four developmental stages. Originally named Environmental Disease Research Centers, they were subsequently renamed Environmental Health Centers following legislative changes. The analysis includes the expansion in the number of centers, the transfer of responsibilities to local governments, and the launch of significant projects such as the Korean Children’s Environmental Health Study (Ko-CHENS ). During the initial phase (May 2007–February 2009), the 10 centers concentrated on research-driven activities, shifting from a media-centered to a receptor-centered approach. In the second phase, prompted by the enactment of the Environmental Health Act, six additional centers were established, broadening their scope to address national environmental health issues. The third phase introduced Ko-CHENS, a 20-year national cohort project designed to influence environmental health policy by integrating research findings into policy frameworks. The fourth phase marked a decentralization of authority, empowering local governments and redefining the centers' roles to focus on regional environmental health challenges. The Regional Environmental Health Centers have significantly evolved and now play a crucial role in addressing local environmental health issues and supporting local government policies. Their capacity to adapt and respond to region-specific challenges is essential for the effective implementation of environmental health policies, reflecting geographical, socioeconomic, and demographic differences.

Stoma formation for fecal diversion is a common procedure in patients with various complicated conditions after colorectal surgery, such as anastomotic leakage. The singleincision laparoscopic approach for stoma creation offers several advantages, including a reduction in surgical wounds and related complications as well as optimal visualization of the surgical field. This video demonstrates a single-port–assisted diverting ileostomy in a 61-yearold man with anastomotic leakage following low anterior resection for advanced rectal cancer.

Background and Objectives: Pediatric chronic rhinosinusitis (CRS) significantly affects children’s quality of life and learning abilities. This study aimed to evaluate the postoperative outcomes in pediatric patients who underwent functional endoscopic sinus surgery (FESS) for CRS. Methods: A retrospective review was conducted on pediatric patients who underwent FESS for CRS at 11 university hospitals. The inclusion criteria were patients under 20 years old with bilateral disease who were operated on between January 2005 and December 2021. The data collected included demographics, clinical history, blood tests, preoperative computed tomography, and preoperative and postoperative symptom control. The Kruskal-Wallis and Fisher exact tests were used to compare the quantitative and qualitative data, respectively. Results: In total, 213 patients were enrolled. The mean age was 13.4±3.0 years, and 145 (68.1%) were male. One hundred sixty-four patients (77.0%) had nasal polyps and 33 patients (15.5%) underwent revision FESS. The preoperative symptoms, in order of prevalence, included nasal obstruction (87.8%), rhinorrhea (71.8%), a sense of postnasal drip (58.2%), hyposmia (44.6%), cough (24.4%), and facial fullness (18.3%). These symptoms were significantly alleviated for up to 3 years after surgery (p<0.001). At the time of the last follow-up, 121 patients (56.8%) were controlled, 80 (37.6%) were partly controlled, and 12 (5.6%) were uncontrolled. Patients in the uncontrolled group had higher Lund-Mackay scores, longer follow-up durations, and more instances of revision surgery compared to those in the controlled and partly controlled groups. When age was categorized into three groups, those aged 16 years or older tended to have lower Lund-Mackay scores and better control. Conclusion FESS significantly improves both the postoperative symptoms and the long-term quality of life in pediatric CRS patients. Better symptom control is associated with older age and a lower disease burden.

Background and Objectives: Outcomes of deferring percutaneous coronary intervention (PCI) without invasive physiologic assessment for intermediate coronary lesions is uncertain.We sought to compare long-term outcomes between medical treatment and PCI of intermediate lesions without invasive physiologic assessment. Methods: A total of 899 patients with intermediate coronary lesions between 50% and 70% diameter-stenosis were randomized to the conservative group (n=449) or the aggressive group (n=450). For intermediate lesions, PCI was performed in the aggressive group, but was deferred in the conservative group. The primary endpoint was major adverse cardiac events (MACE, a composite of all-cause death, myocardial infarction [MI], or ischemia-driven any revascularization) at 3 years. Results: The number of treated lesions per patient was 0.8±0.9 in the conservative group and 1.7±0.9 in the aggressive group (p=0.001). At 3 years, the conservative group had a significantly higher incidence of MACE than the aggressive group (13.8% vs. 9.3%; hazard ratio [HR], 1.49; 95% confidence interval [CI], 1.00–2.21; p=0.049), mainly driven by revascularization of target intermediate lesion (6.5% vs. 1.1%; HR, 5.69; 95% CI, 2.20–14.73;p<0.001). Between 1 and 3 years after the index procedure, compared to the aggressive group, the conservative group had significantly higher incidence of cardiac death or MI (3.2% vs.0.7%; HR, 4.34; 95% CI, 1.24–15.22; p=0.022) and ischemia-driven any revascularization. Conclusions For intermediate lesions, medical therapy alone, guided only by angiography, was associated with a higher risk of MACE at 3 years compared with performing PCI, mainly due to increased revascularization.

Sarcoidosis is an inflammatory condition affecting multiple systems in the body, distinguished by the presence of noncaseating granulomas. It is believed that specific exposures to external antigens in individuals with genetic predisposition lead to the development of these granulomas. When diagnosing sarcoidosis, tuberculosis (TB) is a potential alternative explanation for the symptoms. Our case describes a rare coexistence of cutaneous sarcoidosis and TB pleurisy in a 75-year-old male. He was diagnosed with cutaneous sarcoidosis on his face. During the investigation for possible involvement of other organs, pleural effusion was discovered, and it was determined to be caused by mycobacterial infection. The patient received a 6-month course of anti-TB drugs to treat the TB pleurisy, while a topical calcineurin inhibitor was applied to the cutaneous sarcoidosis. This case serves as a reminder to dermatologists that the coexistence of TB with sarcoidosis is possible, not just as a differential diagnosis.

In forensic science, age estimation is essential for identifying both living and deceased individuals. Teeth and jawbones serve as reliable indicators due to their gradual age-related changes and resistance to environmental factors. Among the various methods, attrition and pulp cavity size are commonly used to estimate adult age. This study aimed to enhance the accuracy of age estimation in Korean adults by combining measurements of tooth attrition and pulp cavity size obtained from panoramic radiographs of mandibular first molars. We evaluated 118 patients (62 male, 56 female) who visited Pusan National University Dental Hospital between 2010 and 2024. Radiographs and clinical photographs were analyzed for grade C teeth with exposed dentin using Takei’s method, and the pulp chamber height ratio (PCHR) and width ratio (PCWR) were measured using Jeon’s method. Intraobserver reliability was high (intraclass correlation coefficient>0.6), with no significant sex-based differences in PCHR and PCWR. Both ratios negatively correlated with age, with PCWR showing a stronger correlation, particularly in females (r=–0.606). This study derived an improved age estimation formula with R² values ranging from 0.540 to 0.546 when both PCHR and PCWR were combined. Despite the limitations of this study, such as its small sample size and reliance on panoramic radiographs, the findings suggest that combining tooth wear and pulp cavity size offers a more robust tool for age estimation in clinical and forensic settings.