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Biomedical subjects

R Iwata

Publications and source records attributed to R Iwata.

At least 127 records · Page 7Linked to original sources
PubMed1981

[The development of the apparatus for the fully automated synthesis of short-lived radiopharmaceutical. --13NH3 automated automated synthesis (author's transl)].

A fully automated apparatus for repeated production of 13NH3 from proton-bombarded water has been developed. Its operation sequence consists of the introduction of NaOH, the bombarded water containing 13NO3- and TiCl3 into a reaction vessel, the distillation of 13NH3 formed by the reduction of the 13NO3-, and the washing of the vessel for the next sequence. The NaOH and TiCl3 are added as 4 ml of saturated solution and 4 ml of 10% aqueous solution, respectively, and halogen lamps are used as the heat source for the distillation. By this apparatus, 13NH3 can be produced automatically and repeatedly in a radiochemical yield of 80-90% within 10 min from the EOB.

Ammonia↗
PubMed1980

[Clinical study of adrenal imaging with 123I-labeled-6 beta-iodomethyl-19-norcholesterol (author's transl)].

Although adrenal scintigraphy with 131I-6 beta-iodomethyl-19-norcholesterol (NCL-6-131I) was used for the first noninvasive imaging of the adrenal glands, it has the disadvantages. These are: (i) relatively high radiation dose to patients, (ii) the long time required for completion of the scan. To solve these problems, 123I-labeled 6 beta-iodomethyl-19-norcholesterol (NCL-6-123I) was synthesized and was used for adrenal scintigraphy in 6 cases. Successful images were obtained with 185 MBq (5 mCi)-260 MBq (7 mCi) of NCL-6-123I, and optimal time required for the satisfactory scan was 2-3 days after the administration. The estimate radiation dose was reduced by using 185 MBq (5 mCi) of NCL-6-123I instead of 18.5 MBq (0.5 mCi) of NCL-6-131I. From the result of this clinical study, NCL-6-123I was preferred for the adrenal scintigraphy.

Adosterol↗
PubMed1978

[Simple method for producing 13NN and 15OO by proton bombardment of aqueous phase (author's transl)].

A simple method has been developed for the production of 13NN and 15OO by proton irradiation of aqueous solutions. 90 mCi of 13NN was obtained in a 200 ml. of He by using 1.0M NH4CI solution at pH 11 as the target with 10 min irradiation of 15 MeV, 10 microamperemeter protons. 80 mCi/min of 15OO was continuously obtained in a 200 ml of O2 by using pure water as the target with 40 MeV, 2 microamperemeter protons. The radiochemical purity of these short-lived radioactive gases obtained by this method was greater than 99.9% by passing through a single absorber.

Ammonium Chloride↗
PubMed1978

[Caffeine-11C, ephedrine-11C and methylephedrine-11C: Synthesis and distribution in mice (author's transl)].

Caffeine, ephedrine and methylephedrine were labeled with carbon-11 by the action of methyliodide-11C on theophylline, norephedrine and ephedrine, respectively. Caffeine-11C was prepared in 44 min with a radiochemical yield of 40%, ephedrine-11C in 45 min with a 11% radiochemical yield and methylephedrine-11C in 36 min with a 43% radiochemical yield. When injected in mice intravenously, these products show a high uptake in the liver, the kidney and the blood for caffeine-11C and in the liver and the kidney for ephedrine-11C and methylephedrine-11C. The brain uptake for these products was found to be 2.4 to 3.9% of the injected dose per gram at 5 min after injection. These studies in mice have demonstrated that these products are potentially useful agents for the dynamic studies of the brain.

Animals↗
PubMed1977

[Remote system for the mass production of short-lived radioisotopes in a cyclotron. Development of the system and radioisotope production].

A system was developed for producing short-lived radioactive substances (11CO, 11CO2, 13NN, 13NH3, 18F-, 62Zn2+, 123I-, etc.) on a scale enough for clinical use, which could also be used for analyzing them rapidly and for investigating their production methods, with less received dose by workers. The system enabled us to produce remotely several tens mCi of of short-lived radioactive susbtances readily usable for clinical diagnosis, continuosly for radioactive gases, 11CO, 11CO2 and 13NN, or repeatedly at short intervals for radioactive aqueous solutions of 13NH3, 18F-, etc. Employing this system, the average received dose per month was reduced considerably.

Carbon Radioisotopes↗