Radiopharmaceuticals are medicinal products that, when ready for use, are labeled with at least one isotope emitting ionizing radiation. Additionally, they contain a molecule responsible for accumulating in specific cells within the body. Radiopharmaceuticals routinely administered to patients are registered as medicinal products and have marketing authorization.
Depending on the type of radiation emitted by these radioisotopes, they may be used for the diagnosis or therapy of various diseases, including oncological conditions. Their applications include imaging of various organs, such as the brain, heart, kidneys, and bones, as well as the treatment of cancer and hyperthyroidism.
Before being administered to a patient, radiopharmaceuticals are thoroughly tested for quality and radiochemical, radionuclidic, and chemical purity, as well as for residual impurities from the synthesis process. The strict quality standards they must meet are regulated by the Polish or European Pharmacopoeia.
International Atomic Energy Agency
Radiopharmaceuticals can be classified based on their method of production, i.e., those produced in a cyclotron or obtained from a generator, or based on their application, diagnostic or therapeutic.
Radiopharmaceuticals produced in a cyclotron
The most commonly used radioisotopes produced by cyclotrons (particle accelerators) are those with a short half-life, meaning they lose a significant portion of their radioactivity within a few hours. As a result, some of them are unsuitable for long-distance transport. These include fluorine-18, carbon-11, oxygen-15, and nitrogen-13, which are dedicated to a type of imaging technique known as positron emission tomography (PET). PET is used to generate high-quality 3D images of target organs or cells in the body for disease diagnosis. Globally, cyclotrons account for 95 percent of radiopharmaceutical production used in PET. The production of radionuclides using an accelerator requires particle beams to be delivered with two specific characteristics: the beams must have sufficient energy to induce the required nuclear reactions, and a sufficient beam current to ensure practical yields.
Cyclotron-based radiopharmaceuticals are produced and synthesized overnight, then undergo quality control testing according to methods described in the pharmacopoeia. During this time, they are transported—typically in the morning, after synthesis—to the target facility. In the meantime, once the quality control tests are approved by a qualified person, the facility receives either a release or rejection of the production batch, which determines whether the radiopharmaceutical can be safely administered to the patient or must be withheld due to failure to meet quality standards.
When the radiopharmaceutical is delivered to the facility along with a positive quality control certificate, it is safe to prepare a patient-specific isotope dose from the bulk vial. Occasionally, a synthesis failure may occur, resulting in unsuccessful radiolabeling. In such cases, a certificate of batch rejection is issued for the radiopharmaceutical, and for patient safety, it cannot be administered. Therefore, the examination is rescheduled for another date, following prior coordination regarding the timing of the next synthesis.
Cyclotron-produced diagnostic radiopharmaceuticals available in our laboratory
[¹⁸F]FDG
[¹⁸F]FLT
[¹⁸F]PSMA-1007
[¹⁸F]Fluorocholine
Generator-produced radiopharmaceuticals
Radionuclide generators serve as a source of radionuclides for the on-site production of radiopharmaceuticals within a given laboratory. The operating principle of a generator is based on the decay of a parent isotope—usually long-lived (less commonly short-lived)—into a short-lived daughter isotope, which is eluted from a chromatographic column and used in the radiolabeling process on-site. In the generator, the parent element is strongly adsorbed onto an appropriate material, while the daughter element exhibits different physical and chemical properties and can be eluted from the parent-daughter mixture.
For example, gallium-68 (Ga-68) is primarily obtained from a germanium-gallium generator, which can be used for only one year and produces a sufficient amount of radionuclide for the diagnosis of four to six patients per day.
The use of a generator helps to avoid the difficulties associated with the distribution of short-lived radionuclides from the primary production site (typically a nuclear reactor) to individual users; the loss of activity due to decay during transport may result in the delivery of insufficient quantities or require the shipment of significantly larger initial amounts.
For labeling, we use a registered and authorized germanium-gallium generator as well as approved commercial kits.
Generator-produced diagnostic radiopharmaceuticals available in our laboratory
[⁶⁸Ga]Ga-PSMA-11
[⁶⁸Ga]Ga-DOTA-TOC
[⁶⁸Ga]Ga-DOTA-TATE
Are radiopharmaceuticals safe?
Radiopharmaceuticals are safe, provided they are used prudently and administered by experienced personnel in controlled conditions, in accordance with radiological and microbiological protection principles. Each use of ionizing radiation must be justified. Your doctor works closely with the radiopharmacist to ensure that the amount of radioactive drug you receive is appropriate and safe. The dose of the administered radiopharmaceutical is individually tailored and calculated for each patient to minimize exposure to ionizing radiation.
Radiopharmaceuticals are thoroughly tested, non-toxic, and do not negatively affect the patient’s well-being.
