Method for Ultratrace Level ²⁴¹Am Determination in Large Soil Samples by Sector Field-Inductively Coupled Plasma Mass Spectrometry: With Emphasis on the Removal of Spectral Interferences and Matrix Effect

A new method using sector field-inductively coupled plasma mass spectrometry (SF-ICPMS) was developed for the determination of ²⁴¹Am in large soil samples to provide realistic soil-plant transfer parameter data for dose assessment of nuclear waste disposal plans. We investigated four subjects: extraction behaviors of interfering elements (Bi, Tl, Hg, Pb, Hf, and Pt) on DGA resin (normal type, abbreviated as DGA-N); soil matrix element removal (Mg, Fe, Al, K, Na) using Fe­(OH)₃, CaF₂, and CaC₂O₄ coprecipitations; Am and rare earth elements (REEs) separation on DGA-N and TEVA resins; and optimization of SF-ICPMS (equipped with a high efficiency nebulizer (HEN)) for Am determination. Our method utilized concentrated HNO₃ to leach Am from 2 to 20 g soil samples. The CaC₂O₄ coprecipitation was used to remove major metals in soil and followed by Am/interfering elements separation using the proposed UTEVA + DGA-N procedure. After a further separation of REEs on TEVA resin, ²⁴¹Am was determined by HEN-SF-ICPMS. This method eliminated the matrix effect in ICPMS ²⁴¹Am measurement for large soil samples. The high decontamination factors (DFs) of interfering elements enable their thorough removal, and in particular, the DF of Pu (7 × 10⁵) was the highest ever reported in ²⁴¹Am studies; thus, this method is capable of analyzing ²⁴¹Pu-contaminated Fukushima Daiichi Nuclear Power Plant (FDNPP) sourced soil samples. A low detection limit of 0.012 mBq g^–1 for ²⁴¹Am was achieved. The chemical recovery of Am (76–82%) was stable for soil samples. This method can be employed for the low level ²⁴¹Am determination in large size soil samples that are contaminated with ²⁴¹Pu

High-Performance Method for Determination of Pu Isotopes in Soil and Sediment Samples by Sector Field-Inductively Coupled Plasma Mass Spectrometry

Plutonium is extensively studied in radioecology (e.g., soil to plant transfer and radiological assessment) and geochemistry (e.g., sediment dating). Here, we reported a new chemical separation method for rapid determination of Pu in soil and sediment samples, based on the following investigations: extraction behaviors of interfering elements (IEs, for inductively coupled plasma mass spectrometry (ICPMS) measurement) on TEVA resin; decontamination of U using TEVA, UTEVA, and DGA resins; and the impact of coprecipitation on Pu determination. The developed method consists of four steps: HNO₃ leaching for Pu release; CaF₂/LaF₃ coprecipitation for the removal of major metals and U; the proposed TEVA + UTEVA + DGA procedure for the removal of U, Pb, Bi, Tl, Hg, Hf, Pt, and Dy; and ICPMS measurement. The accuracy of this method in determining ^239+240Pu activity and ²⁴⁰Pu/²³⁹Pu and ²⁴¹Pu/²³⁹Pu isotopic ratios was validated by analyzing five standard reference materials (soil, fresh water sediment, and ocean sediment). This method is characterized by its stable and high Pu recovery (90–97% for soil; 92–98% for sediment) and high decontamination factor of U (1.6 × 10⁷), which is the highest reported for soil and sediment samples. In addition, the short analytical time of 12 h and the method detection limits, which are the lowest yet reported in literature, of 0.56 μBq g^–1 (0.24 fg g^–1) for ²³⁹Pu, 1.2 μBq g^–1 (0.14 fg g^–1) for ²⁴⁰Pu, and 0.34 mBq g^–1 (0.09 fg g^–1) for ²⁴¹Pu (calculated on the basis of a 1 g soil sample) allow the rapid determination of ultratrace level Pu in soil and sediment samples

Brain Radiotherapy plus Concurrent Temozolomide versus Radiotherapy Alone for Patients with Brain Metastases: A Meta-Analysis

<div><p>Objective</p><p>We performed a meta-analysis of randomized clinical trials to compare the efficacy of brain radiotherapy (RT) combined with temozolomide (TMZ) versus RT alone as first-line treatment for brain metastases (BM).</p><p>Methods</p><p>Medline, Embase, and Pubmed were used to search for relevant randomized controlled trials (RCTs). Two investigators reviewed the abstracts and independently rated the quality of trials and relevant data. The primary outcome was overall survival (OS). Secondary outcomes included progression-free survival (PFS), objective response rate (ORR), and adverse events.</p><p>Results</p><p>Seven studies were selected from the literature search. RT plus TMZ produced significant improvement in ORR with odds ratio (OR) of 2.27 (95% CI, 1.29 to 4.00; <i>P</i> = 0.005) compared with RT alone. OS and PFS were not significantly different between the two arms (OS: HR, 1.00; <i>P</i> = 0.959; PFS: HR, 0.73; <i>P</i> = 0.232). However, the RT plus TMZ arm was associated with significantly more grade 3 to 4 nausea and thrombocytopenia.</p><p>Conclusion</p><p>Concomitant RT and TMZ, compared to RT alone, significantly increases ORR in patients with BM, but yields increased toxicity and fails to demonstrate a survival advantage.</p></div

Forest plot of severe toxicities: (A) nausea; (B) thrombocytopenia.

<p>*Favors RT+TMZ = Lower risk in RT+TMZ.</p

Hazard ratios (HR) and 95% CIs for progression-free survival (PFS).

<p>Hazard ratios (HR) and 95% CIs for progression-free survival (PFS).</p

Forest plot of overall survival (OS) for patients with brain metastases (BM).

<p>Forest plot of overall survival (OS) for patients with brain metastases (BM).</p

Forest plot of subgroup analysis by cancer type for OS.

<p>Forest plot of subgroup analysis by cancer type for OS.</p

Trial Characteristics.

<p>Trial Characteristics.</p

Patient Characteristics.

<p>Patient Characteristics.</p

A flow chart showing the progress of trials through the review.

<p>A flow chart showing the progress of trials through the review.</p