A simple method to shorten the apparent dead time in the dosimetry of Lu-177 for targeted radionuclide therapy using a gamma camera.
Phys Med
; 119: 103298, 2024 Mar.
Article
em En
| MEDLINE
| ID: mdl-38309102
ABSTRACT
BACKGROUND:
The dead-time loss reportedly degrades the accuracy of dosimetry using a gamma camera for targeted radionuclide therapy with Lu-177; therefore, the dead-time loss needs to be corrected. However, the correction is challenging. In this study, we propose a novel and simple method to shorten the apparent dead time rather than correcting it through experiments and Monte Carlo simulations.METHODS:
An energy window of 208 keV ± 10 % is generally used for the imaging of Lu-177. Lower-energy gamma photons and X-rays of Lu-177 do not contribute to image formation but lead to dead-time losses. In our proposed method, a thin lead sheet was used to shield gamma photons and X-rays with energies lower than 208 keV, while detecting 208 keV gamma photons that penetrated the thin sheet. We measured and simulated the energy spectra and count rate characteristics of a clinical gamma camera system using a cylindrical phantom filled with a Lu-177 solution. Lead sheets of 1.0- and 0.5-mm thicknesses were used as thin shields, and the dead-time losses in tumour imaging with consumed Lu-177 were simulated.RESULTS:
The apparent dead times with lead sheets of 1.0- and 0.5-mm thicknesses and without a lead sheet were 1.7, 1.9, and 5.8 µs for an energy window of 208 keV ± 10 %, respectively. The dead-time losses could be reduced from 10 % to 1.3 % using the 1.0-mm thick lead sheet in the simulated imaging of tumour.CONCLUSION:
Our method is promising in clinical situations and studies on Lu-177 dosimetry for tumours.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Radioisótopos
/
Neoplasias
Limite:
Humans
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article