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Count rate characteristics and image distortion in preclinical PET systems during intratherapeutic radiopharmaceutical therapy imaging

Mellhammar, Emma Matilda LU ; Dahlbom, Magnus; Axelsson, Johan LU and Strand, Sven-Erik LU (2016) In Journal of Nuclear Medicine 57(12). p.1964-1970
Abstract

Positron emission tomography (PET) may provide important information on the therapeutic response of radiopharmaceutical therapy (RPT) during therapy. The radiation emission from the RPT radionuclide may disturb the coincidence detection and impair the image resolution. In this study we tested the feasibility to perform intratherapeutic PET on three preclinical PET systems.

METHODS: Using (22)Na point sources and phantoms filled with (18)F, and a phantom filled with either (99m)Tc or (177)Lu, the coincidence count rate and the spatial resolution when both a PET and a therapeutic radionuclide were present in the PET camera, were evaluated. (99m)Tc was used as a substitute for a generic therapeutic radioisotope, since it has a... (More)

Positron emission tomography (PET) may provide important information on the therapeutic response of radiopharmaceutical therapy (RPT) during therapy. The radiation emission from the RPT radionuclide may disturb the coincidence detection and impair the image resolution. In this study we tested the feasibility to perform intratherapeutic PET on three preclinical PET systems.

METHODS: Using (22)Na point sources and phantoms filled with (18)F, and a phantom filled with either (99m)Tc or (177)Lu, the coincidence count rate and the spatial resolution when both a PET and a therapeutic radionuclide were present in the PET camera, were evaluated. (99m)Tc was used as a substitute for a generic therapeutic radioisotope, since it has a suitable half-life and is easy obtainable.

RESULTS: High activities of (99m)Tc deteriorated the coincidence count rate from the (18)F-filled phantom with a (22)Na point source on all three systems evaluated. One of the systems could to a high degree correct the count rate with its dead time correction. The spatial resolution was degraded at high activities of (99m)Tc for all systems. On one of the systems (177)Lu increased the coincidence count rate and slightly affected the spatial resolution. The results for high activities of (177)Lu were similar to those for (99m)Tc.

CONCLUSION: Intratherapeutic imaging might be a feasible method to study RPT treatment response. However, some sensitive preclinical PET systems, unable to handle high count rates, suffer count losses and may also introduce image artifacts.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Nuclear Medicine
volume
57
issue
12
pages
1964 - 1970
publisher
Society of Nuclear Medicine
external identifiers
  • scopus:85001022128
  • wos:000389106800026
ISSN
0161-5505
DOI
10.2967/jnumed.116.175539
language
English
LU publication?
yes
id
e0cfe503-00af-46fd-9754-5decdac4d4f8
date added to LUP
2016-10-20 13:35:06
date last changed
2017-09-18 11:32:08
@article{e0cfe503-00af-46fd-9754-5decdac4d4f8,
  abstract     = {<p>Positron emission tomography (PET) may provide important information on the therapeutic response of radiopharmaceutical therapy (RPT) during therapy. The radiation emission from the RPT radionuclide may disturb the coincidence detection and impair the image resolution. In this study we tested the feasibility to perform intratherapeutic PET on three preclinical PET systems.</p><p>METHODS: Using (22)Na point sources and phantoms filled with (18)F, and a phantom filled with either (99m)Tc or (177)Lu, the coincidence count rate and the spatial resolution when both a PET and a therapeutic radionuclide were present in the PET camera, were evaluated. (99m)Tc was used as a substitute for a generic therapeutic radioisotope, since it has a suitable half-life and is easy obtainable.</p><p>RESULTS: High activities of (99m)Tc deteriorated the coincidence count rate from the (18)F-filled phantom with a (22)Na point source on all three systems evaluated. One of the systems could to a high degree correct the count rate with its dead time correction. The spatial resolution was degraded at high activities of (99m)Tc for all systems. On one of the systems (177)Lu increased the coincidence count rate and slightly affected the spatial resolution. The results for high activities of (177)Lu were similar to those for (99m)Tc.</p><p>CONCLUSION: Intratherapeutic imaging might be a feasible method to study RPT treatment response. However, some sensitive preclinical PET systems, unable to handle high count rates, suffer count losses and may also introduce image artifacts.</p>},
  author       = {Mellhammar, Emma Matilda and Dahlbom, Magnus and Axelsson, Johan and Strand, Sven-Erik},
  issn         = {0161-5505},
  language     = {eng},
  month        = {07},
  number       = {12},
  pages        = {1964--1970},
  publisher    = {Society of Nuclear Medicine},
  series       = {Journal of Nuclear Medicine},
  title        = {Count rate characteristics and image distortion in preclinical PET systems during intratherapeutic radiopharmaceutical therapy imaging},
  url          = {http://dx.doi.org/10.2967/jnumed.116.175539},
  volume       = {57},
  year         = {2016},
}