Evaluated cross-sections of 55 Co radionuclide, a non-standard positron emitter for clinical applications

Khandaker, Mayeen Uddin; Ali, Samer K.I.; Kassim, Hasan Abu; Yusof, Norimah

doi:10.1016/j.radphyschem.2017.01.011

“…Cobalt radionuclides were first synthesized >40 years ago, but there has been a resurgence of interest recently due to the development of more accessible production routes and the increased availability of low-energy cyclotrons. Cobalt-55 (t 1/2 = 17.5 h, E β+ = 570 keV (77%), EC (23%)) 41 is an emerging radioisotope with decay properties suitable for PET imaging with radiolabeled peptides, proteins, and antibody fragments. The positron abundance is >4 times higher than that of 64 Cu; however, this advantage is partially offset by the higher β + energy (570 vs 278 keV), which decreases image quality, and the presence of several high-energy γ rays (477 keV, 20%; 931 keV, 75%; 1409 keV, 17%), which contribute to the patient radiation dose and increase shielding requirements.…”

Section: Common Radionuclides and Their Propertiesmentioning

confidence: 99%

Radioactive Transition Metals for Imaging and Therapy

Boros

¹

,

Packard

²

2018

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Nuclear medicine is composed of two complementary areas, imaging and therapy. Positron emission tomography (PET) and single-photon imaging, including single-photon emission computed tomography (SPECT), comprise the imaging component of nuclear medicine. These areas are distinct in that they exploit different nuclear decay processes and also different imaging technologies. In PET, images are created from the 511 keV photons produced when the positron emitted by a radionuclide encounters an electron and is annihilated. In contrast, in single-photon imaging, images are created from the γ rays (and occasionally X-rays) directly emitted by the nucleus. Therapeutic nuclear medicine uses particulate radiation such as Auger or conversion electrons or β − or α particles. All three of these technologies are linked by the requirement that the radionuclide must be attached to a suitable vector that can deliver it to its target. It is imperative that the radionuclide remain attached to the vector before it is delivered to its target as well as after it reaches its target or else the resulting image (or therapeutic outcome) will not reflect the biological process of interest. Radiochemistry is at the core of this process, and radiometals offer radiopharmaceutical chemists a tremendous range of options with which to accomplish these goals. They also offer a wide range of options in terms of radionuclide half-lives and emission properties, providing the ability to carefully match the decay properties with the desired outcome. This Review provides an overview of some of the ways this can be accomplished as well as several historical examples of some of the limitations of earlier metalloradiopharmaceuticals and the ways that new technologies, primarily related to radionuclide production, have provided solutions to these problems.

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Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals

Lin,

Śmiłowicz,

Joaqui‐Joaqui

et al. 2024

Angewandte Chemie

0

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The elementally matched 55Co (t1/2 = 17.53 h, Iβ+ = 77%)/58mCo (t1/2 = 9.10 h, IC= 100%) radioisotope pair is of interest for development of paired diagnostic/therapeutic radiopharmaceuticals. Due to the accessibility of the Co2+/3+ redox couple, the redox state can be readily modulated. Here, we show that macroscopic and radiochemical redox reactions can be closely monitored and controlled using spectroscopic and radiochemical methods. We employ model systems to inform how to selectively synthesize thermodynamically favored coordination complexes. In addition to exogenous oxidants, our data indicates that 55Co‐induced radiolysis of water efficiently and directly drives selective oxidation to the Co3+ species under no‐carrier added (n.c.a.) conditions. Our synthetic strategies subsequently stabilize the respective 55Co2+ or 55Co3+ species for targeted Co‐compounds’ imaging in a mouse tumor model.

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Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals

Lin,

Śmiłowicz,

Joaqui‐Joaqui

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

The elementally matched 55Co (t1/2 = 17.53 h, Iβ+ = 77%)/58mCo (t1/2 = 9.10 h, IC= 100%) radioisotope pair is of interest for development of paired diagnostic/therapeutic radiopharmaceuticals. Due to the accessibility of the Co2+/3+ redox couple, the redox state can be readily modulated. Here, we show that macroscopic and radiochemical redox reactions can be closely monitored and controlled using spectroscopic and radiochemical methods. We employ model systems to inform how to selectively synthesize thermodynamically favored coordination complexes. In addition to exogenous oxidants, our data indicates that 55Co‐induced radiolysis of water efficiently and directly drives selective oxidation to the Co3+ species under no‐carrier added (n.c.a.) conditions. Our synthetic strategies subsequently stabilize the respective 55Co2+ or 55Co3+ species for targeted Co‐compounds’ imaging in a mouse tumor model.

show abstract

Evaluated cross-sections of 55 Co radionuclide, a non-standard positron emitter for clinical applications

Cited by 6 publications

References 21 publications

Radioactive Transition Metals for Imaging and Therapy

Radioactive Transition Metals for Imaging and Therapy

Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals

Controlling the Redox Chemistry of Cobalt Radiopharmaceuticals

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