{"entity":{"id":"idea-net-dosimetry-prrt","kind":"idea","name":"Dosimetry-personalised PRRT instead of four fixed cycles","aka":[],"tldr":"Measure the radiation each patient's tumour and kidneys actually absorb and adjust the number and size of doses, instead of giving everyone four identical cycles.","summary":"The idea is to personalise peptide receptor radionuclide therapy with lutetium-177 dotatate or 177Lu-edotreotide by measuring the radiation each patient's tumour, kidneys and marrow actually absorb on SPECT/CT after each cycle, and adjusting the number and size of doses. The standard of 7.4 GBq for four cycles leaves many patients under-dosed relative to renal and marrow limits, uptake varies widely, and retrospective dosimetry shows tumour absorbed dose correlates with response. The hypothesis is that dosimetry-guided PRRT raises cumulative tumour dose and response rate without exceeding organ limits. The test is a randomised phase 2 of individualised versus fixed activity; P-PRRT in Canada is already testing this, and the idea addresses the wrong-doses bottleneck.","asOf":"2026-09-07","links":[{"label":"ClinicalTrials.gov NCT03049189: COMPETE","url":"https://clinicaltrials.gov/study/NCT03049189"}],"tags":[],"related":["lu-177"],"indications":["neuroendocrine"],"sections":[],"technologies":["prrt","spect"],"targets":[],"drugs":["lutathera","itm-11"],"companies":[],"institutions":[],"pathways":[],"terms":["dosimetry"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"hypothesis":"Dosimetry-guided PRRT increases cumulative tumour dose and response rate without exceeding renal/marrow limits, versus fixed dosing.","rationale":"Wide inter-patient variation in uptake; SPECT/CT after each cycle makes dosimetry feasible.","test":"Randomised phase 2 of individualised vs fixed activity with ORR and PFS endpoints.","maturity":"early-clinical"},"route":"/ideas/idea-net-dosimetry-prrt/","neighbours":{"isotope":[{"id":"lu-177","kind":"isotope","name":"Lutetium-177","route":"/isotopes/lu-177/"}],"indication":[{"id":"grade-3-net","kind":"indication","name":"Grade 3 well-differentiated neuroendocrine tumour","route":"/indications/grade-3-net/"},{"id":"neuroendocrine","kind":"indication","name":"Neuroendocrine tumours","route":"/indications/neuroendocrine/"},{"id":"pancreatic-net","kind":"indication","name":"Pancreatic neuroendocrine tumours","route":"/indications/pancreatic-net/"},{"id":"small-intestinal-net","kind":"indication","name":"Small intestinal neuroendocrine tumours","route":"/indications/small-intestinal-net/"}],"technology":[{"id":"prrt","kind":"technology","name":"Peptide receptor radionuclide therapy (PRRT)","route":"/technologies/prrt/"},{"id":"spect","kind":"technology","name":"SPECT & bone scan","route":"/technologies/spect/"}],"drug":[{"id":"itm-11","kind":"drug","name":"177Lu-edotreotide","route":"/drugs/itm-11/"},{"id":"lutathera","kind":"drug","name":"Lutetium-177 dotatate","route":"/drugs/lutathera/"}],"term":[{"id":"dosimetry","kind":"term","name":"Dosimetry","route":"/terms/dosimetry/"},{"id":"fixed-versus-personalised-dosing","kind":"term","name":"Fixed versus personalised (dosimetry-guided) dosing","route":"/terms/fixed-versus-personalised-dosing/"}],"bottleneck":[{"id":"b-dosimetry-standardisation","kind":"bottleneck","name":"Dosimetry standardisation for radioligand therapy","route":"/bottlenecks/b-dosimetry-standardisation/"},{"id":"b-dose-optimisation","kind":"bottleneck","name":"Wrong doses","route":"/bottlenecks/b-dose-optimisation/"}],"idea":[{"id":"idea-dosimetry-guided-dosing-standard","kind":"idea","name":"Kidney-dosimetry-guided dosing as the default for PSMA radioligand therapy","route":"/ideas/idea-dosimetry-guided-dosing-standard/"}],"roadmap":[{"id":"dosimetry-roadmap","kind":"roadmap","name":"Dosimetry roadmap: MIRD schema → fixed dosing → personalised, image-based dose","route":"/roadmaps/dosimetry-roadmap/"}]}}