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1

Assessment of the staff absorbed dose related to cyclotron operation and service in the production of 18F radiopharmaceuticals

Sadat-Eshkevar S. M., Karimian A., Mirzaii M.

Nukleonika

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2012

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Vol. 57, No. 3

407-410

EN

Cyclotron accelerators are used to produce medical radioisotopes. One of the most important problems which may be encountered is malfunction of a part of the target or beam line which requires stopping of the bombardment and making a repair. The decision about doing the repair depends on the whole body dose rate in a target room. In this work, dosimetric conditions related to the production of 18FDG radiopharmaceutical were simulated by the Monte Carlo (MC) method. Independently, the dose rates were measured by 7 ICRU spherical body phantoms placed inside the liquid target room and the maze of the cyclotron. The radiation dose rate inside the target room depends on the duration of the bombardment and the time passed after stopping the bombardment. The correlation between duration of the bombardment and required time after stopping the bombardment to reach the absorbed dose rate less than 25 mi Sv/h, was calculated for the presence and absence of the irradiated target. The results showed that the repair can be started immediately after stopping of the proton bombardment only if the target has been ejected from the target room and the duration of bombardment has not taken more than 10 min.

2

Preliminary design and simulation of a spherical brain PET system (SBPET) with liquid xenon as scintillator

Moghaddam N. M., Karimian A., Mostajaboddavati S. M., Vondervoort E., Sossi V.

Nukleonika

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2009

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Vol. 54, No. 1

33-38

EN

Preliminary design of a spherical brain PET (SBPET) using liquid xenon (LXe) as detector is considered in this research work. The major advantage of a spherical design is the large solid angle of acceptance which improves the sensitivity and increases signal-to-noise ratio (SNR) of the image. The use of a liquid active medium enabled us to design a spherical detector. LXe, due to the intrinsic physical properties, is an excellent liquid medium for accurate tracking of gamma rays in the relevant energy range. The performance of SBPET was evaluated by Monte Carlo simulation tools (GATE) and compared to ECAT HRRT. The numerical results showed the SBPET has a sensitivity of 1.14% and spatial resolution of ~2.7 mm FWHM which is superior to ECAT HRRT especially at high-count rates.

3

Production, quality control and initial imaging studies of [82mRb]RbCl for PET studies

Rowshanfarzad P., Jalilian A., Kiyomarsi M., Sabet M., Karimian A., Moradkhani S., Mirzaii M.

Nukleonika

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2006

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Vol. 51, nr 4

209-215

EN

Rubidium-82m was prepared via 15.4 MeV proton irradiation of a krypton-82 gaseous target (30% enrichment). Washing the target chamber with hot water yielded a Rb-82m containing solution, which was further purified using short column chromatography in order to remove organic/inorganic impurities. The flowthrough was formulated in normal saline for injection. Radionuclide, radiochemical and chemical purity tests were performed prior to administration to rats for imaging (radiochemical yield: 95-97%, radiochemical purity > 97%). Preliminary dual-head coincidence studies were performed to determine the distribution of [82mRb]Rb in normal rats. For biodistribution studies, Rb-81 was injected to rats and tracer accumulation in heart, GI and bladder was determined after sacrification in time intervals. A yield of 1.3 GBq at EOB, 235.7 MBq/mAh was obtained.

4

Preparation and biodistribution of [201Tl](III)vancomycin complex in normal rats

Jalilian A., Hosseini M., Karimian A., Saddadi F., Sadeghi M.

Nukleonika

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2006

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Vol. 51, nr 4

203-208

EN

Thallium-201 (T1/2 = 3.04 days) in Tl+ form was converted to Tl3+ cation in presence of O3 in 6 M HCl controlled by RTLC/gel electrophoresis methods. The final evaporated activity was reacted with vancomycin (VAN) in water to yield [201Tl](III)VAN. The best results were obtained at room temperature in water after 30 min with a radiochemical yield > 99%, after mixing the reactants followed by SPE purification using Si Sep-Pak. The studies showed that thallic ion is mostly incorporated into vancomycin with a radiochemical purity of more than 98 š 1% by RTLC. A specific activity of about 4.14 x 1010 Bq/mmol was obtained. Radiochemical purity and stability of 201Tl-VAN in the preparation and in presence of human serum was determined up to 5.5 days. Biodistribution study of 201Tl(III)-vancomycin in normal rats was performed up to 52 h.

5

Development of 62Zn bleomycin as a possible PET tracer

Jalilian A., Fateh B., Ghergherehchi M., Karimian A., Moradkhani S., Kamali-Dehghan M., Tabeie F.

Nukleonika

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2005

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Vol. 50, nr 4

143-148

EN

Abstract Bleomycin (BLM), labeled with radioisotopes, is widely used in therapy and diagnosis. In this study, BLM was labeled with 62Zn for oncologic PET studies. The complex was obtained at pH = 2 in saline at 90°C in 25 min. Radio-TLC showed an overall radiochemical yield of 95 97% (radiochemical purity > 97%). Stability of complex was checked in vitro in mice and human plasma/urine. Preliminary in vivo studies were performed to determine complex stability and distribution of 62Zn BLM in normal and fibrosarcoma-bearing mice. 62Zn BLM accumulated significantly in induced fibrosarcoma tumors in mice according to biodistribution/imaging studies. 62Zn BLM can be used in PET oncology studies due to its suitable physicochemical properties as a diagnostic complex in vitro and in vivo. Further studies should be performed for evaluation of the complex behavior in larger mammals.