RESUMO
A high-speed radiation imaging system based on an image converter of liquid scintillator filled capillary arrays has been developed, which is sensitive to x rays, gamma rays, and neutrons. This imaging system has advantages of both high spatial resolution and high sensitivity because increasing the thickness of the image converter only leads to little deterioration on imaging resolution. The capillary arrays have dimensions of 150 mm diameter and 50 mm thickness, with 100 µm diameter of each capillary. The fluorescence decay time of the filled liquid scintillator based on the mixture of p-xylene and 2,5-diphenyloxazole has been evaluated to be â¼3 ns with the single photon method under the gamma ray excitation. The spatial resolution has been experimentally evaluated to be about 1.15 and 0.6 mm, under excitation of x rays and neutrons, respectively. The imaging system has been applied for diagnosing the dynamic x-ray spot generated by the rod pinch. Two frames in single shot with 15 ns temporal resolution and 20 ns inter-frame separation time have been obtained, which show the spatiotemporal distribution of the electrons bombarding the tungsten rod, indicating the ability of this imaging system in diagnosing dynamic radiation objects. In addition, the technique of capillary arrays provides a promising path for applications of advanced liquid scintillators in the field of radiation imaging.
RESUMO
An image converter based on an indium phosphide has been developed to measure the two-dimensional spatial profile of the incident photon flux by probing the rapid change of the refractive index in the semiconductor. The spatial resolution, dynamic range, and temporal response of this image converter have been investigated with optical methods. The results show that the spatial resolution is â¼15 cycles/mm at the percent modulation transfer function of 0.5, the dynamic range is about 100, and the time response is in the order of 600 ps. This scheme can provide an alternative choice as an imaging diagnostic for experiments in the area of high-energy density physics.
RESUMO
OBJECTIVE: To establish the criteria for screening macroprolactinemia (MP) after Polyethylene glycol (PEG) treatment plus different assays of Prolactin (PRL) in a clinical setting. PATIENTS AND METHODS: This study recruited 122 patients, and their PRL-elevated serum samples were collected. Twenty-two of the 122 serum samples were treated by gel filtration chromatography (GFC) and PEG precipitation. The PRL content in the eluent and supernatant were tested separately by two analyzers: i2000sr (Abbott Laboratories, Chicago, IL, USA) and E170 (Roche Diagnostics, Basel, Switzerland). The GFC-method (the gold standard) was applied, in order to establish the criteria of screening MP after PEG-method. The MP positive rate and PRL concentrations in 100 PRL-elevated patients were compared between the literature criteria (a PRL recovery of < 40%) and the new criteria. RESULTS: The detected value of macroprolactin with the new criteria in the i2000sr (a PRL recovery of < 50%) was higher than in the E170 (a PRL recovery of < 60%). The E170 analyzer detected 38 cases of MP in 100 PRL-elevated samples by using new criteria, which was higher than the literature criteria (24 cases) (p < 0.05). Therefore, there were 15 samples could not be judged consistently using the literature criteria by the i2000sr and E170 analyzers. There was also a significant difference in PRL concentrations between the two groups (p < 0.01). If using the new criteria, the inconsistency between the two analyzers was reduced to 2 samples. There was a very significant difference in the inconsistency between two criteria (p < 0.01). The reported values of PRL from the i2000sr and E170 were 27.8 (16.2-42.6) ng/ml and 32.0 (19.6-49.9) ng/ml. There were no significant differences between two analyzers. CONCLUSIONS: Establishment of different criteria for screening MP by using PEG-method is helpful for the accuracy of PRL determination and its comparability.
