The impact of PET and SPECT on dosimetry for targeted radionuclide therapy.

摘要: Abstract Targeted radionuclide therapy (TRT) is an increasingly used treatment modality for a range of cancers. To date, few treatments have involved the use dosimetry either to plan or retrospectively ascertain absorbed dose delivered during treatment. Also correlation between and biological effect has been difficult establish. Tomographic methods permit determination activity volume on macroscopic scale at different time points. Proper attenuation correction in tomographic imaging requires patient-specific map. This can be obtained from scintillation-camera transmission scanning, CT, by using segmented scatter-emission images. Attenuation corrections performed projection images, reconstructed as part iterative reconstruction method. The problem image quantification radionuclides, particularly I-131, exacerbated fact that most cameras are optimised diagnostic with Tc-99m. In addition, problems may arise when high activities measured due count losses mis-positioned events, because insufficient pile-up dead methods. Sufficient quantification, however, only possible if all effects degrade quantitative content corrected for. Monte Carlo simulations appealing tool help model interactions occurring patient detector system. helpful develop test techniques, define detectors better suited imaging. PET probably accurate method concentrations tissue. considered pre-therapeutic planning but ideally radioisotope same element (e.g. I-124 I-131; Y-86 Y-90). Problems, that – some positron emitting isotopes shorter half-life non-standard procedures availability radiopharmaceutical presently limited; Many 3D-tools -techniques now available physicist clinician enable calculations both target critical organs-at-risk. challenge facing nuclear medicine this methodology routinely clinic, ensure common standard operating centres particular correlate response criteria estimates.