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Macroscopic dosimetry for radioimmunotherapy: Nonuniform activity distributions in solid tumors
Author(s) -
Howell Roger W.,
Rao Dandamudi V.,
Sastry Kandula S. R.
Publication year - 1989
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596404
Subject(s) - radioimmunotherapy , radionuclide , dosimetry , common emitter , electron , context (archaeology) , nuclear medicine , radiochemistry , radionuclide therapy , materials science , atomic physics , chemistry , physics , nuclear physics , optoelectronics , medicine , paleontology , monoclonal antibody , antibody , immunology , biology
In the context of radioimmunotherapy of cancer, there is a need for continued improvement of dosimetry of radionuclides localized in tumors. Current methods assume uniform distribution of radionuclides in the tumor despite experimental evidence indicating nonuniformity. We have developed a model in which nonuniform distribution of radioactivity in the tumor is taken into account. Spherically symmetric radionuclide distributions, depending linearly and exponentially on the radial position, are considered. Dose rate profiles in the tumor are calculated for potentially useful beta‐emitting radionuclides, including 3 2 P, 6 7 Cu, 9 0 Y, 1 1 1 Ag, 1 3 1 I, and 1 8 8 Re, and for 193 m Pt, an emitter of conversion electrons and low‐energy Auger electrons. For the radionuclide distributions investigated, high‐energy beta emitters, such as 9 0 Y, are most effective in treating large tumors (diameter, d ≳1 cm), whereas for small tumors ( d ∼1 mm), medium energy beta emitters such as 6 7 Cu are better suited. Very small tumors ( d <1 mm), and micrometastases are best handled with low‐energy electron emitters such as 193 m Pt.