A case report of image-based dosimetry of bone metastases with Alpharadin ((223)Ra-dichloride) therapy: inter-fraction variability of absorbed dose and follow-up

A 70-year-old man affected by bone metastases from castration resistant prostate cancer underwent Alpharadin ((223)Ra-dichloride) therapy (6 administrations of 50 kBq per kg i.v., once every 4 weeks).

The inter-fraction variability of the absorbed dose to lesions was evaluated for four injections. Dosimetric assessments were performed following the MIRD approach and a recently published methodology. The mean absorbed dose and standard deviation for 4 lesions [mean (σ %)] were: 434 mGy (15 %) and 516 mGy (21 %) for the right and left humeral head, 1205 mGy (14 %) and 781 mGy (8 %) for the right and left glenoid. The estimated total absorbed dose after the whole treatment, considering also the relative-biological effectiveness of alpha particles (RBE = 5), yielded a D RBE range of 13-36 Gy. A good correlation between (99m)Tc and (223)Ra uptake was obtained (R (2) = 0. 7613). The tumour-non-tumour (TNT) ratio of 8 lesions (those above, plus 4 additional), monitored by six (99m)Tc-MDP bone scans over a period of about 10 months, evidenced a TNT reduction in two lesions (-42 and -48 %), but in most lesions the TNT remained fairly constant, evidencing that (223)Ra-dichloride therapy tends to prevent further progression of osseous disease, leading to chronicity of the metastatic status.

Annals of nuclear medicine. 2015 Nov 27 [Epub ahead of print]

Massimiliano Pacilio, Guido Ventroni, Bartolomeo Cassano, Pasquale Ialongo, Leda Lorenzon, Elisabetta Di Castro, Federica Recine, Cora N Sternberg, Lucio Mango

Department of Medical Physics, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy. Department of Nuclear Medicine, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy. Health Physics Postgraduate School, "Sapienza" University of Rome, Piazzale Aldo Moro No. 5, 00185, Rome, Italy. Department of Radiology, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy. Health Physics Postgraduate School, "Sapienza" University of Rome, Piazzale Aldo Moro No. 5, 00185, Rome, Italy. Department of Radiological, Oncological and Anatomo Pathological Sciences, "Sapienza" University of Rome, Viale Del Policlinico No. 155, 00161, Rome, Italy. Department of Medical Oncology, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy.  Department of Medical Oncology, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy. Department of Nuclear Medicine, Azienda Ospedaliera San Camillo Forlanini, Circonvallazione Gianicolense No. 87, 00152, Rome, Italy.  

PubMed

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