Molecular radiotherapy (MRT) using radiopharmaceuticals 131I-mIBG and 177Lu-DOTATATE is increasingly utilized in the treatment regime of primary refractory or relapsed high-risk neuroblastoma. Whilst individualized dosimetric treatment planning is mandatory for external beam radiotherapy and brachytherapy, there is a need for treatment planning or post-therapy dosimetric verification to be implemented in MRT.
Indeed, the avoidance of unacceptable bone marrow and renal toxicities is essential for safety, and knowledge of tumour dose is desirable for correlation for response. Owing to the complexity of the individual disease status and metabolism, there is an unknown relationship between administered activity and absorbed dose. There is therefore a need for precise and accurately delivered tumour and organ sensitive absorbed doses, which will correlate with improved outcomes.
Currently, almost all trials in Europe incorporating MRT are multi-centre as there are too few patients for national statistics or nationally based randomized clinical trials to give reliable and meaningful data in a short time frame. There is therefore an absolute requirement for standardization of methodology for the assessment of dosimetry, which is essential for major European trials incorporating MRT.
UCLH is one of the leading centres in Europe providing MRT for Neuroblastoma. As such, we are key implementers and advisors in the role of dosimetry in MRT for other European sites.
We are using, or intending to use MRT dosimetry in the following open or proposed trials:
We present here our methodology and initial dosimetry results that we aim to see incorporated into all future international trials incorporating MRT, and our role in standardization across centres.