| A Quantitative Whole Body Autoradiography |
Summary: A method for measuring non-destructively the absolute radioactivity distribution of the animal slice that was examined by whole body autoradiography (WARG) was presented. The key step was measuring the thickness (mg/cm2) of each tissue, which was dissolved by radiography using 147Pm plane radiation source. The result of the first trial of quantitative WARG were compared with those obtained measuring the radioactivity directly by rhe combustion method. |
| Reference: Synthesis and Applications of Isotopically Labelled Compounds, Paper 150, 1994, Shigeo BABA |
| Application of radioluminography to off-line counting of radioactivity in high-performance liquid chromatographic eluates |
Abstract: An off-line counting method for the determination of carbon-14 in HPLC eluates was developed using radioluminography (RLG). A succession of aliquots of the eluate were collected in the flat-bottomed wells of a polystyrene microplate, evaporated to dryness and contacted with an imaging plate, and radioactivity was determined with a Bio-Image analyser. The limit of detection was 0.35 Bq per injection. The inter-assay relative standard deviation was less than 3% over the range 2-20 Bq. The RLG off-line counting method was utilized to determine [14C]eicosapentaenoic acid metabolites formed by rat hepatic microsomes. The results were compared with those obtained with an off-line liquid scintillation counting method and an on-line counting method. |
| Reference: Journal of Chromatography A, 663 (1994) 35-41,Shigeo BABA |
| Validation Studies of Radioluminography I Measurement of Background Value |
Summary: A basic study was carried out in order to improve the detection accuracy of radioluminography (RLG) in drug evaluation studies. Back ground value of photo-stimulated luminescence (PSLBG) of an imaging plate (IP) was proven to decrease exponentially in proportion to the wall thickness of exposure vessels without any improvement of SD of PSLBG. This unexpected result was attributed to the fact that a non-uniformity in shielding occured. PSLBG was estimated in terms of β-particles from 32P. When IP was exposed in a shield box, a clear periodicity was observed in the PSLBG. A method for directly measuring the PSLBG of each area was developed, which involved exposing IPs simultaneously and assessing PSLBG of the IP in contact with a 14C from the PSLBGof the corresponding area of th other IPs. Key words: Validation, Radioluminography, Imaging plate (IP), Bio-Imaging analyzer system (BAS), Correction of background value |
| Reference: Xenobio, Metabol. and Dispos. 13(6): 566-571 (1998), Shigeo BABA |
| Validation Studies of Radioluminography II A Method for Monitoring Radioactive Contamination of Imaging Plates |
Summary: A simple method for monitoring radioactive contamination of imaging plates (IP) was proposed. IPs to be examined (IPEX) were exposed under a standardized condition togehter with a few brand-new IPs used for correction of area dependency in background (IPBG) and analyzed using a bio-imaging analyzer system (BAS). The background PSL values (PSLBG) of each 5 x 5 mm area in an IPEX were normalized with those of the corresponding area in IPBG to obtain a normalized PSLBG (PSLBG(nor.)). The areas of radioactive contamination were identified by higher PSLBG(nor.). The detection limit was approximately 6 mBq 14C/25 mm2, when IPs were exposed for 72 hr in a 20 mm brass box. This proposed method makes it possible to retrace past information about radioactive contamination of an IP, when necessary. Key words: Validation, Radioluminography, Imaging plate (IP), Bio-Imaging analyzer (BAS), Radioactive contamination |
| Reference: Xenobio, Metabol. and Dispos. 14(5): 367-370 (1999), Shigeo BABA |
| Validation Studies of Radioluminography III Examination of the Uniformity in β-Ray Sensitivity |
Summary: The validation study on the uniformity in β-ray sensitivity of radioluminography (RLG) has been performed. Imaging plates (IP) were irradiated with a 147PM planar radiation source and then analyzed by two bio-imaging analyzer systems (BAS). The PSL values observed (PSLOB) on the irradiated IPs were statistically analyzed by a split method. An area dependency of appreciable extent in β-ray sensitivity was observed, which could be mainly attributed to the mechanics in BAS. The area dependency in β-ray sensitivity could be corrected using imaging plates that were irradiated with a 147PM planar radiation source. Key words: Validation, Radioluminography, Imaging plate (IP), Bio-Imaging analyzer (BAS), Nonuniformity |
| Reference: Xenobio, Metabol. and Dispos. 15(6): 504-512 (2000), Shigeo BABA |
| Validation Studies of Radioluminography IV Confirmation of the Uniformities in Sensitivity of BAS and IP by USE of a 14C Test Radiation Source |
Summary: A 14C radiation source was prepared for the validation of radioluminography. Each five small polypropylene resin pieces , on which a few hundreds Bq 14C had been spotted accurately and air-dried, were fixed at eaqual intervals on the lengthwise and widthwise center lines and the two diagonal lines on a sheet of cardboard of IP size. Simple methods for daily examining the uniformities in sensitivity of BAS and IP were proposed. Key words: Validation, Radioluminography, Imaging plate (IP), Bio-Imaging analyzer (BAS), Uniformity examination |
| Reference: Xenobio, Metabol. and Dispos. 15(6): 513-518 (2000), Shigeo BABA |
| Measurement of Radioactivity by Microplate-Radioluminography, Development of Microplate-Evaporator. |
Abstract: A simple device for evaporating the sample solutions in 48 well-microplates (MP) was developed in order to facilitate the application of MP-radioluminography (RLG). The proposed device makes it possible to dry-up six MPs containing 0.2 ml water in each well within 1.5 h at one time. The MPs were placed overnight in a desiccator. The cross radioactive contamination accompanied with the evaporation process was not detected. A slight increase in the background photo-stimulated luminescence (PSL) value that was observed in the wells adjacent a radiation well could be attributed to a flare caused during analysis by a bio-imaging analyzer system (BAS). The detection limit of the MP-RLG was 0.005 Bq 14C, when the evaporated MP was brought into contact with an imaging plate for 72 h and analyzed by a BAS. Key words: measurement of radioactivity, microplate, radio-luminography, evaporator, cross-talk |
| Reference: RADIOISOTOPES, 49, 271-275 (2000), Shigeo BABA |
| Detection of radionuclides in capillary electrophoresis using a phosphor-imaging detector. |
Abstract: A capillary electrophoresis (CE) postcolumn radionuclide detector has been developed that uses a commercial phosphor-imaging detector and has been optimized for low-energy beta emitters. Eluant from the separation capillary is deposited on a membrane. Emission from radioactive analytes on the membrane is integrated using the phosphor-imaging system for 10-72 h. Results from the phosphor-imaging system are converted to conventional electropherograms. Modifications to a prior postcolumn CE deposition system have been accomplished by adding a buffer makeup capillary; this increases the electrolyte pH range and improves reproducibility. The limit of detection (LOD) for 35S-labeled analytes is 0.13 amol (8.7 pM or 0.007 Bq), while the LOD for 32P-labeled analytes is 4.9 zmol (0.33 pM or 0.002 Bq), with a linear range for 35S-Met from 1.5 amol to 1.5 fmol. |
| Reference: Department of Chemistry, University of Illinois, Urbana 61801, USA., Tracht SE |