Development and clinical application of targeted alpha therapy using astatine (²¹¹At)

Area of Science:

• Nuclear medicine
• Radiotherapy
• Oncology

Background:

• Targeted alpha therapy (TAT) offers higher efficacy than beta-emitter radionuclide therapy.
• Astatine-211 (²¹¹At) is a promising alpha-emitting radionuclide producible with a 30-MeV cyclotron.
• ²¹¹At functions as an iodine analogue, suitable for thyroid cancer treatment.

Purpose of the Study:

• To evaluate [²¹¹At] NaAt as a targeted alpha therapy for refractory thyroid cancer.
• To assess radiation safety and patient management protocols for ²¹¹At-based TAT.
• To explore the potential of ²¹¹At for broader oncological applications.

Main Methods:

• Investigator-initiated clinical trial using [²¹¹At] NaAt.
• Comparison of radiation dose and exposure with conventional beta-emitters (¹³¹I, ¹⁷⁷Lu).
• Assessment of radiation exposure to the public and caregivers post-administration.

Main Results:

• ²¹¹At requires smaller administration doses compared to beta-emitters.
• ²¹¹At emits lower-energy gamma rays, reducing external radiation exposure.
• Radiation exposure levels were demonstrated to be well below public limits, negating the need for isolation wards.

Conclusions:

• [²¹¹At] NaAt enables targeted alpha therapy for refractory thyroid cancer without requiring inpatient isolation.
• ²¹¹At offers reduced radiation exposure and enhanced safety for patients and caregivers.
• ²¹¹At's imaging capabilities and labeling potential position it as a versatile agent for various cancers.