Astatine-211: Production and Availability

Zalutsky, Michael R.; Pruszyński, Marek

doi:10.2174/1874471011104030177

Cited by 154 publications

(130 citation statements)

References 35 publications

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“…211 At can be cyclotron-produced by bombarding natural bismuth with a medium-energy a-particle beam (28-29.5 MeV) using the 209 Bi(a,2n) 211 At reaction (13). Even though the production and purification of 211 At are inexpensive, the number of accelerators capable of generating a 28-MeV a-particle beam limits the availability of this isotope (13).…”

Section: Atmentioning

confidence: 99%

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α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

et al. 2018

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Learning Objectives: On successful completion of this activity, participants should be able to (1) cite α-emitter families available for therapeutic use and understand their current production limit; (2) consider radiation safety concerns when handling α-emitters; and (3) overcome radiolabeling and daughter redistribution hurdles with the approaches described in this educational review. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, SAM, and other credit types, participants can access this activity through the SNMMI website (http://www.snmmilearningcenter.org) through June 2021.With a short particle range and high linear energy transfer, α-emitting radionuclides demonstrate high cell-killing efficiencies. Even with the existence of numerous radionuclides that decay by α-particle emission, only a few of these can reasonably be exploited for therapeutic purposes. Factors including radioisotope availability and physical characteristics (e.g., half-life) can limit their widespread dissemination. The first part of this review will explore the diversity, basic radiochemistry, restrictions, and hurdles of α-emitters. Radi onuclide strategies for curative therapy, disease control, or palliation are positioned to constitute a major portion of nuclear medicine. The range of available therapeutic radioisotopes, including a, b, or Auger electron emission, has considerably expanded over the last century (1). Matching the particle decay pathway, effective range, and relative biological effectiveness to tumor mass, size, radiosensitivity, and heterogeneity is the primary consideration for maximizing therapeutic efficacy. b-emitting radioisotopes have the longest particle pathlength (#12 mm) and lowest linear energy transfer (LET) (;0.2 keV/mm), supporting their effectiveness in medium to large tumors (Fig. 1). Although the long b-particle range is advantageous in evenly distributing radiation dose in heterogeneous tumors, it can also result in the irradiation of healthy tissue surrounding the tumor site. Conversely, Auger electrons have high LET (4-26 keV/mm) but a limited pathlength of 2-500 nm that restricts their efficacy to single cells, thus requiring the radionuclide to cross the cell membrane and reach the nucleus. Finally, a-particles have a moderate pathlength (50-100 mm) and high LET (80 keV/mm) that render them especially suitable for small neoplasms or micrometastases. A recent clinical study highlighted the ability of a-radiotherapy to overcome treatment resistance to b-particle therapy, prompting a paradigm shift in the approach toward radionuclide therapy (2).For optimized therapeutic efficacy, the a-cytotoxic payload is expected to accumulate selectively in diseased tissue and deliver a suf...

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Section: Atmentioning

confidence: 99%

“…Even though the production and purification of 211 At are inexpensive, the number of accelerators capable of generating a 28-MeV a-particle beam limits the availability of this isotope (13).…”

Section: Atmentioning

confidence: 99%

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

et al. 2018

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“…However, only a limited number of cyclotrons in the world are able to generate a-beam energies beyond 25 MeV, which strongly limits the availability of this radionuclide. 11 Another limitation to consider is the low melting point of the irradiated material (Bismuth mp = 272°C) and its low thermal conductivity (k = 7.9 W m -1 K -1 ). Together, with the relatively high volatility of astatine (337°C), this potentially leads to vaporization of the produced activity due to overheating of the target during the irradiation.…”

Section: Physical Propertiesmentioning

confidence: 99%

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Guérard

Gestin

Brechbiel

2013

Cancer Biotherapy and Radiopharmaceuticals

105

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(211)At is a promising radionuclide for α-particle therapy of cancers. Its physical characteristics make this radionuclide particularly interesting to consider when bound to cancer-targeting biomolecules for the treatment of microscopic tumors. (211)At is produced by cyclotron irradiation of (209)Bi with α-particles accelerated at ~28 MeV and can be obtained in high radionuclidic purity after isolation from the target. Its chemistry resembles iodine, but there is also a tendency to behave as a metalloid. However, the chemical behavior of astatine has not yet been clearly established, primarily due to the lack of any stable isotopes of this element, which precludes the use of conventional analytical techniques for its characterization. There are also only a limited number of research centers that have been able to produce this element in sufficient amounts to carry out extensive investigations. Despite these difficulties, chemical reactions typically used with iodine can be performed, and a number of biomolecules of interest have been labeled with (211)At. However, most of these compounds exhibit unacceptable instability in vivo due to the weakness of the astatine-biomolecule bond. Nonetheless, several compounds have shown high potential for the treatment of cancers in vitro and in several animal models, thus providing a promising basis that has allowed initiation of the first two clinical studies.

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“…Nevertheless, these longer-lived isotopes can only be produced in small quantities 4 , which, combined with their short half-lives and high costs, have considerably limited astatine research. Of the artificial isotopes,…”

mentioning

confidence: 99%

Enigmatic astatine

Wilbur

2013

Nature Chem

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Astatine-211: Production and Availability

Cited by 154 publications

References 35 publications

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Enigmatic astatine

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Astatine-211: Production and Availability

Cited by 154 publications

References 35 publications

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

α-Emitters for Radiotherapy: From Basic Radiochemistry to Clinical Studies—Part 1

Production of [211At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy

Enigmatic astatine

Contact Info

Product

Resources

About

Production of [²¹¹At]-Astatinated Radiopharmaceuticals and Applications in Targeted α-Particle Therapy