Effects of high photon fluence rate from therapeutic radionuclides on preclinical and clinical PET systems
(2016) IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014 In 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014- Abstract
Tumor response in radionuclide therapy can be monitored with PET/CT and/or PET/MR. A high background photon fluence from a therapy radionuclide may influence both image quality and quantification, when imaging is performed intra-therapeutically, i.e. with high activity of the therapeutic radionuclide present. Here, count losses and image distortion have been investigated for preclinical and clinical PET systems with different detector designs. The effect on the spatial resolution was studied with a point source of 22Na in a background of 99mTc, where 99mTc emulated the photon emission from a therapeutic radionuclide. An in-house made mouse phantom with silicon tubes filled with 99mTc with a centrally placed 22Na point source was used.... (More)
Tumor response in radionuclide therapy can be monitored with PET/CT and/or PET/MR. A high background photon fluence from a therapy radionuclide may influence both image quality and quantification, when imaging is performed intra-therapeutically, i.e. with high activity of the therapeutic radionuclide present. Here, count losses and image distortion have been investigated for preclinical and clinical PET systems with different detector designs. The effect on the spatial resolution was studied with a point source of 22Na in a background of 99mTc, where 99mTc emulated the photon emission from a therapeutic radionuclide. An in-house made mouse phantom with silicon tubes filled with 99mTc with a centrally placed 22Na point source was used. For the clinical systems, a 70 cm long NEMA PET Scatter Phantom was used, with a 22Na point source placed at the center whereas the off-center silicon tube was filled with 99mTc. In addition, image quality was also evaluated in the presence of different levels of 99mTc with a 18F-filled NEMA image quality phantom on the preclinical systems and a 18F-filled Jaszczak phantom on the clinical system. Preclinical PET systems with different detector geometries showed that the addition of 99mTc affected the count rate capability considerably, especially those with a low number of read-out channels. The coincidence rate for was significantly reduced when high activities of 99mTc were present. The clinical PET system also showed an effect of reduced coincidence rate with increased photon fluence rate. At high 99mTc activities, the spatial resolution was degraded for both the preclinical and the clinical systems. The quantitative capability of PET systems used intra-therapeutically is significantly affected by the additional high photon fluence rate. The dead-time correction implemented on some of the investigated PET systems, was able to accurately compensate for the coincidence count losses. The reduced spatial resolution at high photon fluence rate, however, remains a potentially limiting factor.
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- author
- Dahlbom, Magnus ; Mellhammar, Emma LU ; Axelsson, Johan LU ; Tran, Thuy LU and Strand, Sven Erik LU
- organization
- publishing date
- 2016-03
- type
- Chapter in Book/Report/Conference proceeding
- publication status
- published
- subject
- host publication
- 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014
- series title
- 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014
- article number
- 7430875
- publisher
- IEEE - Institute of Electrical and Electronics Engineers Inc.
- conference name
- IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014
- conference location
- Seattle, United States
- conference dates
- 2014-11-08 - 2014-11-15
- external identifiers
-
- scopus:84965079418
- ISBN
- 9781479960972
- DOI
- 10.1109/NSSMIC.2014.7430875
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2014 IEEE.
- id
- f058e35b-d9d6-4167-a00a-6686ee61ce0d
- date added to LUP
- 2022-04-04 08:49:32
- date last changed
- 2023-05-15 08:34:25
@inproceedings{f058e35b-d9d6-4167-a00a-6686ee61ce0d, abstract = {{<p>Tumor response in radionuclide therapy can be monitored with PET/CT and/or PET/MR. A high background photon fluence from a therapy radionuclide may influence both image quality and quantification, when imaging is performed intra-therapeutically, i.e. with high activity of the therapeutic radionuclide present. Here, count losses and image distortion have been investigated for preclinical and clinical PET systems with different detector designs. The effect on the spatial resolution was studied with a point source of 22Na in a background of 99mTc, where 99mTc emulated the photon emission from a therapeutic radionuclide. An in-house made mouse phantom with silicon tubes filled with 99mTc with a centrally placed 22Na point source was used. For the clinical systems, a 70 cm long NEMA PET Scatter Phantom was used, with a 22Na point source placed at the center whereas the off-center silicon tube was filled with 99mTc. In addition, image quality was also evaluated in the presence of different levels of 99mTc with a 18F-filled NEMA image quality phantom on the preclinical systems and a 18F-filled Jaszczak phantom on the clinical system. Preclinical PET systems with different detector geometries showed that the addition of 99mTc affected the count rate capability considerably, especially those with a low number of read-out channels. The coincidence rate for was significantly reduced when high activities of 99mTc were present. The clinical PET system also showed an effect of reduced coincidence rate with increased photon fluence rate. At high 99mTc activities, the spatial resolution was degraded for both the preclinical and the clinical systems. The quantitative capability of PET systems used intra-therapeutically is significantly affected by the additional high photon fluence rate. The dead-time correction implemented on some of the investigated PET systems, was able to accurately compensate for the coincidence count losses. The reduced spatial resolution at high photon fluence rate, however, remains a potentially limiting factor.</p>}}, author = {{Dahlbom, Magnus and Mellhammar, Emma and Axelsson, Johan and Tran, Thuy and Strand, Sven Erik}}, booktitle = {{2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014}}, isbn = {{9781479960972}}, language = {{eng}}, publisher = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}}, series = {{2014 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2014}}, title = {{Effects of high photon fluence rate from therapeutic radionuclides on preclinical and clinical PET systems}}, url = {{http://dx.doi.org/10.1109/NSSMIC.2014.7430875}}, doi = {{10.1109/NSSMIC.2014.7430875}}, year = {{2016}}, }