scholarly journals Radioiodination and Purification of [131I]β-CIT and [131I]FP-CIT with an Automated Radiosynthesizer

2022 ◽  
Vol 15 (1) ◽  
pp. 96
Author(s):  
Elisabeth Plhak ◽  
Edith Gößnitzer ◽  
Reingard M. Aigner ◽  
Herbert Kvaternik
Keyword(s):  
Solid Phase ◽  
Single Photon ◽  
Photon Emission ◽  
Tropane Alkaloids ◽  
Radiochemical Yield ◽  
Emission Computed Tomography ◽  
Dopaminergic Dysfunction ◽  
Free Iodine ◽  
Iodine 131 ◽  
Photon Emission Computed Tomography

Dopaminergic transporter (DAT) imaging with single photon emission computed tomography (SPECT) is used to diagnose Parkinson’s disease and to differentiate it from other neurodegenerative disorders without presynaptic dopaminergic dysfunction. The radioiodinated tropane alkaloids [123I]FP-CIT and [123I]β-CIT enable the evaluation of the integrity of DATs. Commonly, the labeling of these compounds is performed by electrophilic substitution of the alkylstannylated precursors with radioactive iodine and following purification by HPLC or solid phase extraction (SPE). This work presents the first radioiodination of β-CIT and FP-CIT with no carrier added [131I]NaI on a Scintomics GRP synthesis module. Free iodine-131 and impurities were removed by SPE over a C-18 Sep-Pak cartridge. We achieved a radiochemical yield of >75% and a radiochemical purity of >98% with both compounds. Our development of an automated synthesis on a commercially available synthesizer ensures robust and efficient labeling of [131I]FP-CIT and [131I]β-CIT starting with low concentrated radioiodine.

scholarly journals Production, purification, and radiolabeling of the 203Pb/212Pb theranostic pair

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Brooke L. McNeil ◽  
Andrew K. H. Robertson ◽  
Winnie Fu ◽  
Hua Yang ◽  
Cornelia Hoehr ◽  
...  
Keyword(s):  
Solid Phase ◽  
Single Photon ◽  
Lead Isotopes ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
The Novel ◽  
Production Methods ◽  
Single Photon Emission Computed ◽  
Photon Emission Computed Tomography ◽  
Acetate Form

Abstract Background Lead-212 (212Pb, t1/2 = 10.6 h) and lead-203 (203Pb, t1/2 = 51.9 h) are an element-equivalent, or a matched theranostic radioisotope pair that show great potential for application in targeted radionuclide therapy (TRT) and single-photon emission computed tomography (SPECT), respectively. At TRIUMF we have produced both 203Pb and 212Pb using TRIUMF’s TR13 (13 MeV) and 500 MeV cyclotrons, and subsequently purified and evaluated both radioisotopes using a series of pyridine-modified DOTA analogues in comparison to the commercially available chelates DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and TCMC (1,4,7,10-tetraaza-1,4,7,10-tetra(2-carbamoylmethyl)cyclododecane). Results Proton irradiation (12.8 MeV) of natural and enriched thallium-203 (203Tl) targets gave 203Pb saturation yields of 134 ± 25 and 483 ± 3 MBq/μA, respectively. Thorium-228 (228Th, t1/2 = 1.9 y), a by-product of 232Th proton spallation on TRIUMF’s main 500 MeV beamline (beamline 1A, BL1A), was recovered to build a 228Th/212Pb generator with the ability to deliver up to 9–10 MBq of 212Pb daily. Both lead isotopes were purified via solid phase extraction chromatography (Pb resin), and isolated in an acetate form ([203/212Pb]Pb(OAc)2) suitable for direct radiolabeling of chelators and bioconjugates. A series of cyclen-based chelators (herein referred to as DOTA-1Py, -2Py, and -3Py) along with established chelates DOTA and TCMC were evaluated for their ability to complex both 203Pb and 212Pb. All chelates incorporated 212Pb/203Pb efficiently, with higher radiolabeling yields observed for the 212Pb-complexes. Conclusion The production of 203Pb and 212Pb was established using TRIUMF 13 MeV and 500 MeV cyclotrons, respectively. Both production methods provided radiometals suitable for subsequent radiolabeling reactions using known and novel chelates. Furthermore, the novel chelate DOTA-3Py may be a good candidate for biomolecule conjugation and further theranostic 212Pb/203Pb studies.

Comparison between planar and single-photon emission computed tomography images for radiation intensity quantification in iodine-131 scintigraphy

2021 ◽  
Author(s):  
Yusuke Iizuka ◽  
Tomohiro Katagiri ◽  
Minoru Inoue ◽  
Kiyonao Nakamura ◽  
Takashi Mizowaki
Keyword(s):  
Radiation Dose ◽  
Single Photon ◽  
Photon Emission ◽  
Correlation Coefficients ◽  
Emission Computed Tomography ◽  
Planar Images ◽  
Iodine 131 ◽  
The Mean ◽  
Photon Emission Computed Tomography ◽  
Spect Images

Abstract This study aimed to evaluate the feasibility of quantifying iodine-131 (131I) accumulation in scintigraphy images and compare planar and single-photon emission computed tomography (SPECT) images to estimate 131I radioactivity in patients receiving radioactive iodine therapy for thyroid cancer. We evaluated 72 sets of planar and SPECT images acquired between February 2017 and December 2018. Simultaneously, we placed a reference 131I capsule next to the patient during image acquisition. We evaluated the correlation between the intensity of the capsule in the images and the capsule dose and estimated the radiation dose at the thyroid bed. The mean capsule dose was 2.14 MBq (range, 0.63–4.31 MBq). The correlation coefficients (p-value) between capsule dose and maximum and mean intensities in both planar and SPECT images were 0.93 (p < 0.01), 0.96 (p < 0.01), 0.60 (p < 0.01), and 0.47 (p < 0.01), respectively. The mean intensities of planar images show the highest correlation coefficients. Based on a regression equation, the average radiation dose in the thyroid bed was 5.9 MBq. In conclusion, planar images reflected the radiation dose more accurately than SPECT images. The regression equation allows to determine the dose in other regions, such as the thyroid bed or sites of distant metastasis.

scholarly journals Production, Purification, and Radiolabeling of the 203Pb/212Pb Theranostic Pair

2020 ◽  
Author(s):  
Brooke L McNeil ◽  
Andrew K. H. Robertson ◽  
Winnie Fu ◽  
Hua Yang ◽  
Cornelia Hoehr ◽  
...  
Keyword(s):  
Solid Phase ◽  
Single Photon ◽  
Lead Isotopes ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
The Novel ◽  
Production Methods ◽  
Single Photon Emission Computed ◽  
Photon Emission Computed Tomography ◽  
Acetate Form

Abstract Background: Lead-212 (212Pb, t1/2 = 10.6 h) and lead-203 (203Pb, t1/2 = 51.9 h) are an element-equivalent, or a matched theranostic radioisotope pair that show great potential for application in targeted radionuclide therapy (TRT) and single-photon emission computed tomography (SPECT), respectively. At TRIUMF we have produced both 203Pb and 212Pb using TRIUMF’s TR13 (13 MeV) and 500 MeV cyclotrons, and subsequently purified and evaluated both radioisotopes using a series of pyridine-modified DOTA analogues in comparison to the commercially available chelates DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and TCMC (1,4,7,10-tetraaza-1,4,7,10-tetra(2-carbomoylmethyl)cyclododecane).Results: Proton irradiation (12.8 MeV) of natural and enriched thalium-203 (203Tl) targets gave 203Pb saturation yields of 134 ± 25 and 483 ± 3 MBq/μA, respectively. Thorium-228 (228Th, t1/2 = 1.9 y), a by-product of 232Th proton spallation on TRIUMF’s main 500 MeV beamline (beamline 1A, BL1A), was recovered to build a 228Th/212Pb generator with the ability to deliver up to 9-10 MBq of 212Pb daily. Both lead isotopes were purified via solid phase extraction chromatography (Pb resin), and isolated in an acetate form ([203/212Pb]Pb(OAc)2) suitable for direct radiolabeling of chelators and bioconjugates. A series of cyclen-based chelators (herein referred to as DOTA-1Py, -2Py, and -3Py) along with established chelates DOTA and TCMC were evaluated for their ability to complex both 203Pb and 212Pb. All chelates incorporated 212Pb/203Pb efficiently, with higher radiolabeling yields observed for the 212Pb-complexes. Conclusion: The production of 203Pb and 212Pb was established using TRIUMF 13 MeV and 500 MeV cyclotrons, respectively. Both production methods provided radiometals suitable for subsequent radiolabeling reactions using known and novel chelates. Furthermore, the novel chelate DOTA-3Py may be a good candidate for biomolecule conjugation and further theranostic 212Pb/203Pb studies.

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