Abstract
Background177Lu-DOTATATE is a valuable treatment option for patients with advanced neuroendocrine tumours overexpressing somatostatin receptors. Though well tolerated in general, bone marrow toxicity can, besides renal exposure, become dose limiting and affect the ability to sustain future therapies. The aim of this study was to develop a novel planar image-based method for bone marrow dosimetry and evaluate its correlation with haematological toxicity during 177Lu-DOTATATE treatment. In this study, 46 patients with advanced neuroendocrine tumours were treated with 7.2 GBq (3.5–8.3 GBq) of 177Lu-DOTATATE on two to five occasions. Planar gamma camera images were acquired at 2, 24, 48 and 168 h post-injection. Whole-body regions of interest were created in the images, and a threshold-based segmentation algorithm was applied to separate the uptake of 177Lu-DOTATATE into high and low uptake compartments. The conjugate view method was used to quantify the activity, the accumulated activity was calculated and the absorbed dose to the bone marrow was estimated according to the MIRD scheme. Patients were monitored for haematological toxicity based on haemoglobin (Hb), white blood cell (WBC) and platelet (PLT) counts every other week during the treatment period.ResultsThe mean absorbed dose to the bone marrow was estimated to 0.20 Gy (0.11–0.37 Gy) per 7.4 GBq of 177Lu-DOTATATE, and the mean dose per fraction correlated with a decrease in Hb (p = 0.01), WBC (p < 0.01) and PLT (p < 0.01) counts. The total mean absorbed dose to the bone marrow was 0.64 Gy (0.30–1.5 Gy) per 24 GBq (8.2–37 GBq) of 177Lu-DOTATATE and also correlated with a decrease in Hb (p < 0.01), WBC (p = 0.01) and PLT (p < 0.01) counts.ConclusionsThe planar image-based method developed in this study resulted in similar absorbed doses to the bone marrow as reported in earlier studies with blood-based bone marrow dosimetry. The results correlated with haematological toxicity, making it a promising method for estimating bone marrow doses in 177Lu-DOTATATE treatment without the need for blood and urine sampling.
Highlights
IntroductionThe aim of this study was to develop a novel planar image-based method for bone marrow dosimetry and evaluate its correlation with haematological toxicity during 177Lu-DOTATATE treatment
177Lu-DOTATATE is a valuable treatment option for patients with advanced neuroendocrine tumours overexpressing somatostatin receptors
Bone marrow dosimetry is only performed occasionally, and instead haematological toxicity monitored in terms of haemoglobin (Hb), white blood cell (WBC) and platelet (PLT) counts serves as a surrogate of bone marrow function
Summary
The aim of this study was to develop a novel planar image-based method for bone marrow dosimetry and evaluate its correlation with haematological toxicity during 177Lu-DOTATATE treatment. The conjugate view method was used to quantify the activity, the accumulated activity was calculated and the absorbed dose to the bone marrow was estimated according to the MIRD scheme. Patients were monitored for haematological toxicity based on haemoglobin (Hb), white blood cell (WBC) and platelet (PLT) counts every other week during the treatment period. Treatment with 177Lu-labelled somatostatin analogues (177Lu-DOTATATE) for patients with advanced neuroendocrine tumours has been proven safe and efficient [1,2,3]. Bone marrow dosimetry is only performed occasionally, and instead haematological toxicity monitored in terms of haemoglobin (Hb), white blood cell (WBC) and platelet (PLT) counts serves as a surrogate of bone marrow function. Serious haematological toxicity (grade 3–4 according to NCI CTCAE version 3.0) is reported in 10 % of treated patients, and long-term effects in terms of myelodysplastic syndrome or leukaemia are described in 1–2 % of treated patients [1, 9]
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