[en] Lumped constant (LC) is the ratio of FDG metabolism ratio to glucose metabolism ratio. There is different LC in the different tissue, and the different physiologic condition in a tissue can also result in the different LC. In this paper authors summarize LC values in several tissue and the method to calculation them, and introduce several simple method to get input function

[en] The anion-exchange behavior of neptunium ions was studied by the use of ²³⁹Np. Neptunium adsorbed on the column of Dowex-1 resin was eluted with nitric acid. The shape of the resulting curves was studied by changing the experimental conditions of eluting solution and by using exchanger with different degree of cross linkage. The oxidation states of neptunium were assigned by coprecipitation tests with sample drops taken from the vicinity of elution peaks. From the position of peaks of the elution curves, K_d values for Np (V) and Np (VI) were calculated. The K_d value of Np (V) is a second power dependence on the acidity of eluting solution, whereas that for Np (VI) gives first power dependence. Such relationships for Np (V) and Np (VI) coincide with those of Pa (V) and U (VI), respectively. K_d values of actinide ions in the oxidation state of IV, increase with increase of atomic number but those of (V) and (VI) give reverse relation; e. g. the K_d values for Np (V) and Np (VI) are smaller than those of Pa (V) and U (VI), respectively. Np (VI) is eluted out before Np (V) with nitric acid of the concentration higher than 6M, but the reverse relationships hold for lower concentrations. K_d values give linear relationship with the degree of cross linkage of the anion exchanger up to 8 when 6M nitric acid was used as eluant. (author)

No abstract available

[en] The influence factor on efficiency of ¹⁸F-FDG is investigated with '2-pot' system to improve the yield of ¹⁸F-FDG. The synthesis efficiency is leaded to low in evidence by water in synthesis system which it comes from K2.2.2 or acetonitrile of delivered tube. The lower impurity of recovery H₂¹⁸O also lead to low yield. The Triflate more than 15 mg can accord with operating requirement. The shortened synthesis time will benefit to EOS. The synthesis time shorten from 55 min to 44 min, EOB can be increased from 50% to 65% by optimized synthesis time and controlled less water in synthesis

[en] N-succinimidyl-4-[¹⁸F]fluorobenzoate([¹⁸F]SFB) was prepared using a multifunction chemistry process control unit module. The dried K₂₂₂/¹⁸F^- was resolubilized with a solution of 4-trimethlammoniumbenzoate trifluoromethane-sulfonate and reacted to produce ethyl-4-[¹⁸F] fluorobenzoate. The ethylester was subsequently hydrolyzed using alkali to obtain the 4-[¹⁸F] fluorobenzoic acid([¹⁸F]FBA). After purifying through Sep-Pak C18 cartridge, [¹⁸F]FBA was dissolved with TSTU in CH₃CN and reacted to produce [¹⁸F]SFB. The nucleophilic reaction reated for 10 min at 115 degree C in the covered vial, mixturing solvents with netrogen for several seconds and the ethylester was subsequently hydrolyzed using alkali. The decay-corrected yields of [¹⁸F]SFB were much higher. The radiochemical yield of [¹⁸F]SFB is (28.2±1.9) (n=5), and radiochemical purity of [¹⁸F]SFB is more than 90%. The whole reaction time is only 45 min from ¹⁸F-F^- to [¹⁸F]SFB. The whole reaction time can be shorten and the yield of product is high by using the multifunction chemistry process control unit module. It is a quick and highly efficient method for labeling bioactive compound. (authors)

[en] Objective: To determine the pixel radioactive concentration using the pixel counts on dual-head coincidence detection (DHC) FDG images. Methods: To convert the count rate per pixel into radioactivity concentration, the calibration factor (CF) was determined by phantom studies. The DHC equipment was produced by GE Hawkeye. The phantom was Toshiba AZ-618 SPECT phantom. Emission scanning was performed for 18 times with the radioactivity escalating stepwise at a range of 15.15-204.33 MBq. Results: 1) The CF depended on the detected single count rate, and the relationship was expressed with a biquadratic polynomial. 2)The radioactive concentration of lesion pixel depended on the pixel counts, the acquisition time and CF, and the relationship was expressed with an empirical formula. Conclusion: A method for calculating the pixel radioactive concentration is developed and it would lay the foundation for quantitative analysis of DHC images

[en] 2-[¹⁸F]-fluoro-2-deoxy-D-glucose (¹⁸F-FDG) is synthesized using ultrasound promoted method (UPM). The results show that the 2-nucleophilic substitution of F ion has relationship with phase-transfer catalyst and reaction temperature. The ultrasound promoted nucleophilic substitution reaction can finish 70% under 84 degree C for 10 min without catalyst, 85% under 22 degree C for 10 min with 10 mg catalyst and 95% under 84 degree C for 2 min with 10 mg catalyst. Comparing with CTI method, the utilization of F ion of UPM improves 10% and the radioactivity absorption on vessel decreases 5%. The EOS is 60% and EOB is 78% in synthesis time of 40 min using UPM. The free F ion of ¹⁸F-FDG is lower than 1% after one C-18 column purification. So ¹⁸F-FDG synthesis yield can be proved obviously using UPM

[en] Objective: To calculate the radioactivity disposition in endovascular irradiation for preventing restenosis after angioplasty and to give an empirical formula easy to use. Methods: 1) The process of intravascular brachytherapy with ⁹⁰Y, ¹⁸⁸Re or ³²P filled balloon was simulated with the computer program based on beta particle dose point kernel; and the absorbed dose distribution was calculated. 2) The curve of absorbed dose rate versus the outer radius of the balloon and the penetrating depth in the vessel wall were fitted to a function with non-linear least squares method and an empirical formula easy to use was built. Results: The absorbed doses distributing along the radial direction of the standard balloon showed that the peak value was inside the balloon, and the inflexion of the dose curve was at the endothelial surface of the vessel. The dose decreased sharply with the radial distance approximately in an exponential manner in the vessel wall. The relationship of absorbed dose to radiation time, initial radioactivity, tissue depth, balloon outer radius were all expressed with an empirical formula. Conclusions: The dose decreases sharply within the vessel wall, and that is very advantageous for focusing radiation energy on the vessel wall and preventing damaging distant normal tissue. Using the empirical formula, according to the required absorbed dose, the required radiation time can be easily calculated for clinical purpose

[en] Objective: To make a simple device for automatic synthesis of ¹⁸F-FDG. Methods: The ¹⁸F was processed by azeotropic drying with anhydrous acetonitrile using hot air bath at the temperature of 116 degree C for two times. Subsequently triflate precursor was added at an air bath temperature of 85-90 degree C for 3-5 min. Acetonitrile was evaporated at 116 degree C. The residue was cooled down to 40 degree C with air bath and the residue was dissolved in 2 mL 0.3 mol/L NaOH for 2 min. The aqueous solution was neutralized and purified with Dowex-50W/ AG11A8 resin and Alumin-N, C-18 column. Results: The device can synthesize ¹⁸F-FDG within 20 min, and the radiochemical yield was 61% [42%-70%, n=60, end of synthesis (EOS)]. Conclusion: The technology and automatic device can synthesize ¹⁸F-FDG with high yield within a short time, and it can be used in PET centers

[en] Objective: To assess PET reconstructed image effected by different ¹⁸F-FDG dosages with quantitative and qualitative analysis. Methods: To perform PET phantom acquisition by routine clinical parameters after filled with different doses of ¹⁸F-FDG solution. An identical slice was extracted from reconstructed image for doing following analysis: the hot area standard uptake value (SUV), the ratio of hot area to cold area, the standard deviation on background area, the ratio of true coincidence to random. Results: 296 MBq: The image uniformity was terribly worse, T/R=0.83, other indexes were irregular. 148 MBq: The image presentation looked like the image without attenuation correction, T/R=1.64, other indexes were moderate. 74, 37 and 18.5 MBq: The images were with excellent uniformity, resolution and contrast, the background noise was suitable, all of the quantitative indexes were good. 9.25 and 4.625 MBq: The uniformity and resolution was degraded terribly because of the higher noise and lower information. Conclusion: Combining above results with other considerations, such as radiation exposure, information amount and acquisition time, the authors think the optimal dosage should be 4.625-11.1 MBq/kg