Diagnostic procedures imply the administration of activity levels that do not lead to the appearance of radiation deterministic effects; therefore only stochastic risks have to be considered.
Autologous marrow transplantation or peripheral blood stem cell reinfusion has been investigated as a means to overcome bone marrow toxicity in RIT, thereby allowing administration of activity doses more than twice as high as without any bone marrow support.
Performing a study within the workers' own department, aiming at the optimization of a procedure used in the preparation and administration of activity for imaging or therapy, is an excellent way to achieve radiation awareness, to educate and train workers, and to show compliance with dose limits.
An increasingly common protocol is to deliver a whole-body absorbed dose of 4 Gy in two administrations of activity separated by 2 weeks, followed by stem cell rescue.
Conclusion: While the pump infusion techniques produce uniform and homogeneous perfusates, gravity technique was found to deliver a variable content perfusate making difficult the control of cumulative perfused activity, and perilous the planning administration of partial activities following dose adjustments.
The half-life of 213Bi results in a low bone marrow dose in humans, allowing administration of high activities.
However, the high toxicity of α-emitting radionuclides often does not permit administration of high activities for fear of normal tissue toxicity.
According to recently established guidelines, peptide receptor radionuclide therapy (PRRT) consists in the systemic administration of fixed activities of radiolabeled somatostatine analogues, usually fractionated in sequential cycles of 6 12 weeks [2].
The short half-life in combination with relatively long retention time in the peritoneal cavity of the patient allows administration of higher activities, and the resulting irradiation from unbound 213Bi-antibodies in the surrounding i.p. fluid could substantially contribute to a high absorbed dose to microtumors.
Such partnership may increase resources to improve the infrastructure at CBE sites, provide accommodation of trainees or transport to communities, finance the administration of CBE activities or provide social amenities for the welfare of the trainees at site tutors.
