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Quantitative imaging of 223Ra-chloride (Alpharadin) for targeted alpha-emitting radionuclide therapy of bone metastases.

Hindorf, Cecilia LU ; Chittenden, Sarah; Aksnes, Anne-Kirsti; Parker, Chris and Flux, Glenn (2012) In Nuclear Medicine Communications 33(7). p.726-732
Abstract
OBJECTIVE: Ra is an alpha particle emitter that targets areas of increased bone turnover in bone metastases. Alpha particles account for 95% of the 27.8 MeV emitted per decay. Less than 2% of the emissions are from photons. This means that a high absorbed dose will be delivered locally, although the number of photons for imaging will be low. The purpose of this study was to investigate the possibility of quantitative imaging of Ra to enable biodistribution studies. METHODS: A Philips Forte gamma camera, equipped with a medium-energy collimator, was used. Basic imaging parameters were determined from phantom studies, and the accuracy of activity quantification was tested in a phantom study and within a patient study. RESULTS: Imaging... (More)
OBJECTIVE: Ra is an alpha particle emitter that targets areas of increased bone turnover in bone metastases. Alpha particles account for 95% of the 27.8 MeV emitted per decay. Less than 2% of the emissions are from photons. This means that a high absorbed dose will be delivered locally, although the number of photons for imaging will be low. The purpose of this study was to investigate the possibility of quantitative imaging of Ra to enable biodistribution studies. METHODS: A Philips Forte gamma camera, equipped with a medium-energy collimator, was used. Basic imaging parameters were determined from phantom studies, and the accuracy of activity quantification was tested in a phantom study and within a patient study. RESULTS: Imaging parameters were determined for the three most suitable photon peaks from the acquired energy spectrum (82, 154 and 270 keV). Camera sensitivity is constant for circular sources with areas greater than 10 cm. The spatial resolution (full-width at half-maximum) was 1.1 cm for each of the three energy windows. The possibility for quantitative imaging was further investigated for the 82 keV energy window, which showed the highest sensitivity and spatial resolution. A phantom study showed that activity could be quantified to within 10% for a 200 ml volume placed within water containing background activity and to within 50% for a 0.5 ml phantom. Quantification of activity in bone after administrations of 100 kBq/kg of Ra-chloride proved the feasibility of quantitative imaging of patients who have received radionuclide therapy. CONCLUSION: Because of the high-energy deposition of Ra, only a low injected activity is required for therapy, which results in a low count rate for the gamma camera. Nevertheless, this study has demonstrated that it is possible to quantify uptake with a sufficient degree of accuracy to obtain clinically relevant information. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ra-223, alpha particles, quantitative imaging, targeted radionuclide, therapy
in
Nuclear Medicine Communications
volume
33
issue
7
pages
726 - 732
publisher
Lippincott Williams & Wilkins
external identifiers
  • wos:000305500600007
  • pmid:22513884
  • scopus:84862239106
ISSN
1473-5628
DOI
10.1097/MNM.0b013e328353bb6e
language
English
LU publication?
yes
id
bf060c61-ed9a-487c-a2d5-fe173e8628f6 (old id 2519293)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/22513884?dopt=Abstract
date added to LUP
2012-07-25 10:56:28
date last changed
2017-10-22 03:02:23
@article{bf060c61-ed9a-487c-a2d5-fe173e8628f6,
  abstract     = {OBJECTIVE: Ra is an alpha particle emitter that targets areas of increased bone turnover in bone metastases. Alpha particles account for 95% of the 27.8 MeV emitted per decay. Less than 2% of the emissions are from photons. This means that a high absorbed dose will be delivered locally, although the number of photons for imaging will be low. The purpose of this study was to investigate the possibility of quantitative imaging of Ra to enable biodistribution studies. METHODS: A Philips Forte gamma camera, equipped with a medium-energy collimator, was used. Basic imaging parameters were determined from phantom studies, and the accuracy of activity quantification was tested in a phantom study and within a patient study. RESULTS: Imaging parameters were determined for the three most suitable photon peaks from the acquired energy spectrum (82, 154 and 270 keV). Camera sensitivity is constant for circular sources with areas greater than 10 cm. The spatial resolution (full-width at half-maximum) was 1.1 cm for each of the three energy windows. The possibility for quantitative imaging was further investigated for the 82 keV energy window, which showed the highest sensitivity and spatial resolution. A phantom study showed that activity could be quantified to within 10% for a 200 ml volume placed within water containing background activity and to within 50% for a 0.5 ml phantom. Quantification of activity in bone after administrations of 100 kBq/kg of Ra-chloride proved the feasibility of quantitative imaging of patients who have received radionuclide therapy. CONCLUSION: Because of the high-energy deposition of Ra, only a low injected activity is required for therapy, which results in a low count rate for the gamma camera. Nevertheless, this study has demonstrated that it is possible to quantify uptake with a sufficient degree of accuracy to obtain clinically relevant information.},
  author       = {Hindorf, Cecilia and Chittenden, Sarah and Aksnes, Anne-Kirsti and Parker, Chris and Flux, Glenn},
  issn         = {1473-5628},
  keyword      = {Ra-223,alpha particles,quantitative imaging,targeted radionuclide,therapy},
  language     = {eng},
  number       = {7},
  pages        = {726--732},
  publisher    = {Lippincott Williams & Wilkins},
  series       = {Nuclear Medicine Communications},
  title        = {Quantitative imaging of 223Ra-chloride (Alpharadin) for targeted alpha-emitting radionuclide therapy of bone metastases.},
  url          = {http://dx.doi.org/10.1097/MNM.0b013e328353bb6e},
  volume       = {33},
  year         = {2012},
}