Clinical radionuclide therapy dosimetry: the quest for the "Holy Gray".
BACKGROUND
Radionuclide therapy has distinct similarities to, but also profound differences from external radiotherapy.


METHODS
This review discusses techniques and results of previously developed dosimetry methods in thyroid carcinoma, neuro-endocrine tumours, solid tumours and lymphoma. In each case, emphasis is placed on the level of evidence and practical applicability. Although dosimetry has been of enormous value in the preclinical phase of radiopharmaceutical development, its clinical use to optimise administered activity on an individual patient basis has been less evident. In phase I and II trials, dosimetry may be considered an inherent part of therapy to establish the maximum tolerated dose and dose-response relationship. To prove that dosimetry-based radionuclide therapy is of additional benefit over fixed dosing or dosing per kilogram body weight, prospective randomised phase III trials with appropriate end points have to be undertaken. Data in the literature which underscore the potential of dosimetry to avoid under- and overdosing and to standardise radionuclide therapy methods internationally are very scarce.


CONCLUSIONS
In each section, particular developments and insights into these therapies are related to opportunities for dosimetry. The recent developments in PET and PET/CT imaging, including micro-devices for animal research, and molecular medicine provide major challenges for innovative therapy and dosimetry techniques. Furthermore, the increasing scientific interest in the radiobiological features specific to radionuclide therapy will advance our ability to administer this treatment modality optimally.
Brans
B
B
Department of Nuclear Medicine, University Hospital Maastricht, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands. b.brans@lnug.azm.nl.
Bodei
L
L
Division of Nuclear Medicine, Istituto Europeo di Oncologia, Milan, Italy.
Giammarile
F
F
Service de Médecine Nucléaire, Centre Léon Bérard, Lyon, France.
Linden
O
O
Department of Oncology, Lund University Hospital, Lund, Sweden.
Luster
M
M
Department of Nuclear Medicine, University of Würzburg, Würzburg, Germany.
Oyen
W J G
WJG
Department of Nuclear Medicine, University Medical Center Nijmegen, Nijmegen, The Netherlands.
Tennvall
J
J
Department of Oncology, Lund University Hospital, Lund, Sweden.
D019797:3-Iodobenzylguanidine / Q000627:therapeutic use; D000818:Animals; D002986:Clinical Trials as Topic; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008223:Lymphoma / Q000532:radiotherapy*; D020714:Maximum Tolerated Dose; D018358:Neuroendocrine Tumors / Q000532:radiotherapy*; D010455:Peptides / Q000627:therapeutic use; D016499:Radioimmunotherapy / Q000379:methods; D011874:Radiometry / Q000379:methods*; D011878:Radiotherapy; D013964:Thyroid Neoplasms / Q000532:radiotherapy*
D007457:Iodine Radioisotopes; D010455:Peptides; D019797:3-Iodobenzylguanidine