Other therapeutic radionuclides

Lutetium-177 has been identified as a suitable radionuclide for targeted therapy of various malignant disorders. Some of the participants were introduced to the chemistry of Lu and the application of other therapeutic radionuclides for the first time. The sourcing of Lu, a radionuclide that can... 

In addition to the above mentioned radioisotopes, several other cyclotron-produced, useful or potentially useful, therapeutic radionuclides, e.g., Tb (Ty2 = 4.1 h = 3.97 MeV), Nd... 

Labelled compounds have found broad application in various fields of science and technology. A great variety of labelled compounds are applied in nuclear medicine. The compounds are produced on a large scale as radiopharmaceuticals in cooperation with nuclear medicine, mainly for diagnostic purposes and sometimes also for therapeutic application. The study of metabolism by means of labelled compounds is of great importance in biology. More details on the application of radionuclides and labelled compounds in medicine and other areas of the life sciences will be given in chapter 19. 

Small antibody fragments can be converted into therapeutic agents by modification with suitable radionuclides, drugs (using cleavable linkers or liposomal preparations), enzymes catalyzing prodrug conversion, cytokines, pro-coagulant factors, photosensitizers, and other classes of... 

Fig. 6.3 Targeting moieties (ligands) can be converted into imaging or therapeutic agents by modification with suitable radionuclides, fluorophores, drugs, enzymes, cytokines or other bioactive molecules.

The above discussion has focused on a comparison of Y and l because these are the most frequently utilized radionuclides in endoradiotherapy however, the effect of particle range on therapeutic utility has been evaluated theoretically for other radionuclides as well. For a comprehensive discussion of the relationship between tumor size and therapeutic effectiveness for 22 uniformly distributed P emitters, the reader is referred to a paper by O Donoghue et al. (1995). In this study, a model was developed that took into account both tumor radiosensitivity and proliferation and yielded the diameter of tumor that could be optimally treated by each radionuclide. These ranged from 0.6 mm for to 3.4 cm for Y. A tumor control probability model has also been utilized to compare the potential therapeutic efficacy of six P emitters (Nahum 1996). 

Some radionuclides are emitting a combined spectrum of radiation. One type of the radiation spectrum (alpha or beta) is used for its therapeutic properties the other type of the radiation spectrum (gamma) might be used for localisation of the tracer and the targeted tissue or for dosimetry. These radiopharmaceuticals are called theranostics. 

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