[en] It was shown that the k_0-method using the recently developed extended Hogdahl formalism for non-1/ν nuclides and neutron temperatures from thermocouple readings can give k_0-NAA results for Eu and Lu accurate to about 1 %. The necessary Q_0 and k_0 values for "1"5"1Eu(n,γ)"1"5"2Eu, "1"5"1Eu(n,γ)"1"5"2"mEu and "1"7"6Lu(n,γ)"1"7"7Lu were measured by reactor irradiation of certified standards and gamma-ray counting. The present measurements of k_0-values did not confirm the previously published values; they were higher by 6 % for "1"5"2Eu and by 16 % for "1"5"2"mEu. (author)

[en] In neutron activation analysis the sample to be analysed is counted with the same detection efficiency as the standard or else a correction factor is determined to correct for the difference. The components contributing to the uncertainty of the detection efficiency correction factor were identified and evaluated by using "1""2Ta gamma-rays for typical NAA samples counted 1 and 100 mm from the detector. Uncertainties as high as 20 % were found due to coincidence summing and gamma attenuation. It was shown how to incorporate these components into the NAA uncertainty budget. (author)

[en] The k₀ values of 6 non-1/v nuclides (¹⁵²Eu, ¹⁵²mEu, ¹⁵⁴Eu, ¹⁷⁷Lu, ¹⁹²Ir and ¹⁹⁴Ir) were determined using the extended Hogdahl formalism at the research reactor FRM II with very high f values. Standards were irradiated in 4 channels at different local temperatures between 40 °C and 55 °C measured using temperature sensitive irreversible labels. A good agreement with the recommended values was found for ¹⁵²Eu, ¹⁵⁴Eu and ¹⁷⁷Lu using the original g(T_n) factors by Gryntakis, however, the k₀ values for ^152mEu in this work were 7% higher. New k₀ values were also determined using the g(T_n) factors by Van Sluijs. Differences up to 6% were found for Eu isotopes compared with the recommended values. The recommended k₀ values for ¹⁹²Ir and ¹⁹⁴Ir could be confirmed using g = 1. The theoretical k₀ values for ¹⁷⁷Lu were calculated using new nuclear data. They are up to 6% less than the recommended values. The present k₀ values determined in this work showed a similar trend. The influence of different g(T_n) factors on the determination of the k₀ values was investigated. (author)

[en] In the WEPAL IPE 2009.2 proficiency test, Jozef Stefan Institute (JSI) participated by measuring Cr by k₀-INAA; it was the only laboratory providing data by an instrumental technique. The JSI Cr result was about 38% higher than the assigned value in plant sample 124 (Lucerne/Medicago sativum). The same sample was again studied in 2012. This time, more labs, including JSI, used instrumental techniques and the average Cr result was higher and consistent with the 2009 and 2012 JSI results. From the results obtained in the present study, involving four INAA labs, it is confirmed that Cr losses in this sample occurred during the chemical digestion required by the techniques applied by other laboratories, illustrating the inherent advantage of nuclear techniques to be almost matrix independent and independent of the chemical state of the element under study. (author)

[en] The uniaxial strain dynamic densification behavior of cerium dioxide powders as a function of powder compact green density is investigated in this work. Cerium dioxide powders of two particle morphologies (rod-like and equiaxed) and two green densities (55% and 62.5% TMD) are shock compressed using the gas gun with specifically designed fixtures and their particle and shock wave velocities are measured using VISAR and multiple PDV probes. The obtained data describe the Hugoniot of the shocked cerium dioxide powders. Finally, the method used to produce this high fidelity Hugoniot data for cerium dioxide powders is discussed and preliminary data are shown.

[en] Intraoperative molecular imaging (IMI) with folate-targeted NIR tracers has been shown to improve lesion localization in more than 80% of lung adenocarcinomas. However, mucinous adenocarcinomas (MAs) and invasive mucinous adenocarcinomas (IMAs) of the lung, which are variants of adenocarcinoma, appear to have decreased fluorescence despite appropriate folate receptor expression on the tumor surface. We hypothesized that the etiology may be related to light excitation and emission through non-Newtonian fluid (mucin) produced by goblet and columnar cancer cells. Intraoperative data for 311 subjects were retrospectively reviewed from a prospectively collected 6-year database. For standardization, all patients underwent infusion of the same targeted molecular optical contrast agent (pafolacianine, folate receptor-targeted NIR fluorochrome) for lung cancer resections. Then, the ratio of the mean fluorescence intensity of the tumors and background tissues (TBR) was calculated. Tumors were examined for mucin, FRa, FRb, and immunofluorescent tracer uptake by a board-certified pathologist. The optical properties of mucin analyzed by imaging software were used to create in vitro gel models to explore the effects on NIR tracer fluorescence intensity. A large proportion (192, 62%) of the patients were female, with an average of 62.8 years and a 34-year mean pack smoking history. There were no severe (Clavien-Dindo > III) complications related to pafolacianine infusion. A total of 195 lesions in the study were adenocarcinomas, of which 19 (6.1%) were of the mucinous subtype. A total of 14/19 of the patients had a smoking history, and more than 74% of the IMA lesions were in the lower lobes. IMA lesions had a lower in situ TBR than nonmucinous adenocarcinomas (2.64 SD 0.23) vs (3.45 SD 0.11), respectively (p < 0.05). Only 9/19 (47%) were localized in situ. Tumor bisection and removal of mucin from IMAs significantly increased pafolacianine fluorescence, with resultant TBR not being significantly different from the control group (4.67 vs 4.89) (p = 0.19). Of the 16 lesions that underwent FR expression analysis, 15/16 had FR presence on cancer cells or tumor-associated macrophages in the tumor microenvironment. There was no statistically significant difference in fluorescence intensity during immunofluorescence analysis (4.99 vs 5.08) (p = 0.16). Physical removal of mucin from IMAs improved the TBR from 3.11 to 4.67 (p < 0.05). In vitro analysis of the impact of synthetic non-Newtonian fluid (agarose 0.5%) on NIR tracer fluorescence showed a decrease in MFI by a factor of 0.25 regardless of the concentration for each 5 mm thickness of mucin. The mucinous subtype of lung adenocarcinomas presents a unique challenge in pafolacianine-targeted IMI-guided resections. The presence of non-Newtonian fluids presents a physical barrier that dampens the excitation of the tracer and fluorescence emission detected by the camera. Knowledge of this phenomenon can allow the surgeon to critically analyze lesion fluorescence parameters during IMI-guided lung cancer resections.

[en] The diagnostic yield of biopsies of solitary pulmonary nodules (SPNs) is low, particularly in sub-solid lesions. We developed a method (NIR-nCLE) to achieve cellular level cancer detection during biopsy by integrating (i) near-infrared (NIR) imaging using a cancer-targeted tracer (pafolacianine), and (ii) a flexible NIR confocal laser endomicroscopy (CLE) system that can fit within a biopsy needle. Our goal was to assess the diagnostic accuracy of NIR-nCLE ex vivo in SPNs. Twenty patients with SPNs were preoperatively infused with pafolacianine. Following resection, specimens were inspected to identify the lesion of interest. NIR-nCLE imaging followed by tissue biopsy was performed within the lesion and in normal lung tissue. All imaging sequences (n = 115) were scored by 5 blinded raters on the presence of fluorescent cancer cells and compared to diagnoses by a thoracic pathologist. Most lesions (n = 15, 71%) were adenocarcinoma-spectrum malignancies, including 7 ground glass opacities (33%). Mean fluorescence intensity (MFI) by NIR-nCLE for tumor biopsy was 20.6 arbitrary units (A.U.) and mean MFI for normal lung was 6.4 A.U. (p < 0.001). Receiver operating characteristic analysis yielded a high area under the curve for MFI (AUC = 0.951). Blinded raters scored the NIR-nCLE sequences on the presence of fluorescent cancer cells with sensitivity and specificity of 98% and 97%, respectively. Overall diagnostic accuracy was 97%. The inter-observer agreement of the five raters was excellent (κ = 0.95). NIR-nCLE allows sensitive and specific detection of cancer cells in SPNs. This technology has far-reaching implications for diagnostic needle biopsies and intraprocedural decision-making.

[en] Pafolacianine, a folate receptor alpha-targeted NIR tracer, has demonstrated clear efficacy in intraoperative molecular imaging-guided (IMI) lung cancer surgery. However, the selection of patients who would benefit from IMI remains challenging given the variability of fluorescence with patient-associated and histopathologic factors. Our goal in this study was to prospectively evaluate whether preoperative FRα/FRβ staining can predict pafolacianine-based fluorescence during real-time lung cancer resections. This was a prospective study conducted between 2018 and 2022 that reviewed core biopsy and intraoperative data from patients with suspected lung cancer. A total of 196 patients were deemed eligible, of whom core biopsies were taken from 38 patients and assessed for FRα and FRβ expression by immunohistochemistry (IHC). All patients underwent infusion of pafolacianine 24 h prior to surgery. Intraoperative fluorescence images were captured with the VisionSense bandpass filter-enabled camera. All histopathologic assessments were performed by a board-certified thoracic pathologist. Of the 38 patients, 5 (13.1%) were found to have benign lesions (necrotizing granulomatous inflammation, lymphoid aggregates) and 1 had metastatic non-lung nodule. Thirty (81.5%) had malignant lesions, with the vast majority (23, 77.4%) being lung adenocarcinoma (7 (22.5%) SCC). None of the benign tumors (0/5, 0%) exhibited in vivo fluorescence (mean TBR of 1.72), while 95% of the malignant tumors fluoresced (mean TBR of 3.11 ± 0.31) compared to squamous cell carcinoma (1.89 ± 0.29) of the lung and sarcomatous lung metastasis (2.32 ± 0.09) (p < 0.01). The TBR was significantly higher in the malignant tumors (p = 0.009). The median FRα and FRβ staining intensities were both 1.5 for benign tumors, while the FRα and FRβ staining intensities were 3 and 2 for malignant tumors, respectively. Increased FRα expression was significantly associated with the presence of fluorescence (p = 0.01), This prospective study sought to determine whether preoperative FRα and FRβ expression on core biopsy IHC correlates with intraoperative fluorescence during pafolacianine-guided surgery. These results, although of small sample size, including limited non-adenocarcinoma cohort, suggest that performing FRα IHC on preoperative core biopsies of adenocarcinomas as compared to squamous cell carcinomas could provide low-cost, clinically useful information for optimal patient selection which should be further explored in advanced clinical trials.