Radiopharmaceutical therapy dosimetry

6 problems

• Microdosimetry of $\alpha$ emitters with mobile daughters

  Open

  Alpha-emitting drugs release a chain of short-lived radioactive descendants, which can break free of the carrier molecule and travel elsewhere in the body before decaying. Where that dose ends up is not known.

• Cell killing by Auger emitters located outside the nucleus

  Open

  Some radioactive atoms release electrons that mostly travel less than a thousandth of a millimetre, so they should harm a cell only if they are right next to its DNA. Reports of killing when the atoms are on the cell surface or in other compartments challenge that picture.

• Does absorbed dose predict outcome in radionuclide therapy?

  Partially resolved

  In external beam treatment, more dose means more tumour control. Whether the same holds for radioactive drugs, where dose arrives slowly and unevenly, has not been shown convincingly.

• Accelerator production routes for therapeutic alpha emitters

  Partially resolved

  The most promising alpha-emitting drugs are limited by how little of the isotope can be made. Which production reaction is best is not settled.

• Quantitative imaging of low-yield therapeutic emitters

  Open

  To compute the dose, the drug must be seen and counted inside the body, but alpha-emitting drugs give off very few detectable photons.

• Dose at the scale of nephrons and marrow cavities

  Open

  Organ-average dose hides the fact that a drug concentrates in particular microscopic structures, such as parts of the kidney filter or pockets of bone marrow.