DSpace Community:

CdSe/CdZnS core/shell nanocrystal scintillators: Light yield, decay time, and solvent effects

2026-03-30T08:29:20Z

Title: CdSe/CdZnS core/shell nanocrystal scintillators: Light yield, decay time, and solvent effects Authors: Boo, Jihwan; Kim, Byong Jae; Kim, Nam Young; Han, Ill-hyuk; Lim, Soobin; Lim, Jaehoon; Kim, Geehyun Abstract: Semiconductor nanocrystals (NCs) have emerged as promising candidates for next-generation scintillators owing to their tunable band gaps and high photoluminescence quantum yields (PLQYs). However, most NC-based scintillators rely on polymer or solvent matrices, in which inefficient energy transfer and self-absorption significantly limit their light yield. In this study, we developed solvent- and polymer-free CdSe/CdZnS NC films (50-200 mu m thick) and quantitatively evaluated their gamma-ray response and its light yield through single-photoelectron (SPE)-based measurements. The NC films preserved their intrinsic optical characteristics after fabrication and exhibited distinct photopeaks at 59.5 keV (Am-241) and 81.0 keV (Ba-133), achieving a light yield of approximately 3200 +/- 100 photons/MeV with a fast decay time of similar to 20 ns-comparable to reported NC/polymer nanocomposite scintillators. We further investigated solvent effects using NC-doped liquid scintillators, revealing the importance of solvent selection for observing measurable scintillation signals.

Impact of trastuzumab deruxtecan (T-DXd) and brain stereotactic radiosurgery on intracranial control and radionecrosis risk in HER2-positive or -low breast cancer brain metastases

2026-04-13T08:35:30Z

Title: Impact of trastuzumab deruxtecan (T-DXd) and brain stereotactic radiosurgery on intracranial control and radionecrosis risk in HER2-positive or -low breast cancer brain metastases Authors: Chun, Seok-Joo; Kim, Kyubo; Chang, Won Ick; Kim, Yong Bae; Ha Paek, Sun; Lee, Kyung-Hun; Song, Jin-Ho; Hong, Ji Hyun; Lee, Jieun; Il Jang, Won; Kim, Tae Hyun; Shin, Kyung Hwan Abstract: Background While trastuzumab deruxtecan (T-DXd) demonstrates intracranial efficacy, the potential for radionecrosis (RN) when combined with stereotactic radiosurgery (SRS) remains a concern, given the established risk with other antibody-drug conjugates like T-DM1. This study evaluated the safety and efficacy of T-DXd and SRS in patients with HER2-positive or -low breast cancer brain metastases (BCBM). Methods We conducted a multi-center retrospective analysis of 113 patients (461 SRS treatments) treated with SRS and anti-HER2 agents. Patients were stratified into T-DXd(+) (n = 29 patients, 61 treatments) and T-DXd(-) (n = 84 patients, 400 treatments) groups. Endpoints included RN, radionecrosis-free survival (RNFS), and intracranial control outcomes (any intracranial progression, local failure, and distant intracranial metastasis). Results No cases of RN were observed in the T-DXd(+) group, compared with 11 cases in the T-DXd(-) group (p = 0.028). On multivariate analysis, T-DXd(+) status remained significantly associated with improved RNFS (HR 0.31, p = 0.009). In the treatment-level analysis, the 1-year cumulative incidence of RN was 0% for T-DXd(+) versus 4.3% for T-DXd(-) (p = 0.009). Additionally, T-DXd(+) was associated with significantly better 1-year outcomes for any intracranial progression (40% vs. 76%, p < 0.001), local failure (6.6% vs. 29%, p = 0.002), and distant intracranial metastasis (40% vs. 66%, p = 0.009). All efficacy endpoints remained significant on multivariate analysis. Conclusion Combining T-DXd with SRS demonstrated a favorable safety profile without increasing the risk of radionecrosis. Furthermore, this combination was associated with superior intracranial control, encompassing both local and distant outcomes, supporting the potential of T-DXd combined with SRS as an effective and well-tolerated approach for HER2-positive or -low BCBM.

Metastasis-directed radiotherapy for oligometastatic cervical carcinoma: Identifying potential beneficiaries

2026-03-30T08:32:51Z

Title: Metastasis-directed radiotherapy for oligometastatic cervical carcinoma: Identifying potential beneficiaries Authors: Lee, Won Hee; Park, Sangjoon; Wee, Chan Woo; Kim, Yong Bae; 이원희 Abstract: Background: The role of metastasis-directed radiotherapy (MDRT) in oligometastatic cervical carcinoma (OCC) remains unclear. This study evaluated clinical outcomes of MDRT in patients with OCC and identified prognostic factors associated with survival. Materials and methods: Patients with OCC who received MDRT between 2019 and 2022 were retrospectively reviewed. Eligible patients had <= 5 metastatic lesions treated using stereotactic ablative radiotherapy (SABR), defined as radiotherapy delivered in <= 5 fractions with a fractional dose of >= 5 Gy. Oligometastatic disease was classified according to the ESTRO-EORTC consensus. Radiologic response, patterns of failure, progression-free survival (PFS), overall survival (OS), and treatment-related toxicities were analyzed. Results: A total of 83 patients with 114 temporally independent MDRT courses delivered using SABR were included. Repeat oligorecurrence was the most common oligometastatic subtype, observed in 35 patients. Lymph nodes were the most frequently treated sites (37 patients, 44.6%). Systemic therapy was administered either before and/or after MDRT in 54 patients (65.1%). With a median follow-up of 20 months, the local control rate was 60.8%, and disease progression predominantly occurred outside the treated fields. The 2-year PFS and OS rates were 14.5% and 62.9%, respectively. In multivariable analysis, oligometastatic disease classification and RT response were independently associated with OS. No grade 3 or higher treatment-related toxicities were observed. Conclusion: MDRT using SABR achieved favorable outcomes with minimal toxicity in OCC. Oligometastatic disease classification may assist in selecting appropriate patients for MDRT under multidisciplinary approach. Prospective studies are warranted to validate these findings and to define optimal MDRT strategies.

A prospective study for brain metastasis imaging screening in patients with advanced HER2-positive or triple-negative breast cancer

2026-03-31T01:10:46Z

Title: A prospective study for brain metastasis imaging screening in patients with advanced HER2-positive or triple-negative breast cancer Authors: Kim, G. M.; Kim, M. H.; Park, H. S.; Kim, J. H.; Kim, K. H.; Kim, S. -G.; Kim, J. Y.; Park, H, S.; Park, S.; Lee, S. -K.; Kim, Y. B.; Chang, J. H.; Kim, S. I.; Sohn, Joo Hyuk; 김건민; 김민환; 김지예; 박형석; 이승구; 김용배; 장종희; 김승일 Abstract: Background: Current guidelines for advanced breast cancer do not recommend routine brain imaging in neurologically asymptomatic patients. Prospective clinical evidence on the effectiveness of screening for early detection of brain metastasis (BM) remains limited. We conducted a prospective cohort study to evaluate the utility of magnetic resonance imaging (MRI) screening in patients with advanced human epidermal growth factor receptor 2-positive (HER2+) or triple-negative breast cancer (TNBC). Patients and methods: In this single-arm, prospective study, screening brain MRI was carried out at diagnosis in asymptomatic patients with advanced HER2+ or TNBC. Patients without BM on baseline MRI were monitored for the development of neurologic symptoms. Follow-up brain MRI studies were carried out at the initiation of second-and third-line systemic therapy. The primary endpoint was the detection rate of BM on screening MRI. Results: MRI detected asymptomatic BM in 11/112 (9.8%) patients at baseline; the cumulative detection rates increased to 17.0% and 19.6% by the initiation of second-and third-line therapy, respectively. Through this serial screening strategy, two-thirds of all BM cases (22/33) were identified at an asymptomatic stage. Patients with baseline metastatic involvement of three or more organ sites outside the central nervous system had an increased risk of BM (hazard ratio 3.38), and 38.5% of patients in this subgroup were diagnosed with BM by MRI screening. Stereotactic radiosurgery (66.7%) was the most common initial treatment for BM, and the median overall survival after BM diagnosis was 23.3 months. Conclusions: Two-thirds of BM cases in patients with advanced HER2+ or TNBC were diagnosed at an asymptomatic stage in this prospective serial brain MRI screening program.