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Monte Carlo investigation of PET [68Ga]Ga-DOTA-TOC activity-administration protocols for consistent image quality

Kalaitzidis, Philip LU ; Gustafsson, Johan LU ; Hindorf, Cecilia LU and Ljungberg, Michael LU (2023) In Heliyon 9(9).
Abstract

One example of a PET exam that suffers from noise problems is [68Ga]Ga-DOTA-TOC, where patients are generally administered between 100 and 200 MBq [68Ga]Ga-DOTA-TOC, irrespective of size. However, a fixed activity can result in low signal-to-noise ratios (SNRs) in larger patients. This study aimed to evaluate the impact on image quality with respect to injected activity and patient habitus through Monte Carlo (MC) simulation. Eight anthropomorphic computer phantoms with body mass indices (BMIs) between 19 kg/m2 and 38 kg/m2 and tumours distributed in the liver were simulated using the MC software Gate v8.2 with an activity distribution defined according to [68Ga]Ga-DOTA-TOC... (More)

One example of a PET exam that suffers from noise problems is [68Ga]Ga-DOTA-TOC, where patients are generally administered between 100 and 200 MBq [68Ga]Ga-DOTA-TOC, irrespective of size. However, a fixed activity can result in low signal-to-noise ratios (SNRs) in larger patients. This study aimed to evaluate the impact on image quality with respect to injected activity and patient habitus through Monte Carlo (MC) simulation. Eight anthropomorphic computer phantoms with body mass indices (BMIs) between 19 kg/m2 and 38 kg/m2 and tumours distributed in the liver were simulated using the MC software Gate v8.2 with an activity distribution defined according to [68Ga]Ga-DOTA-TOC standardised uptake values. Three activity-administration protocols were simulated: (i) with a fixed activity of 100 MBq, (ii) with the activity scaled by 2 MBq/kg, and (iii) with the activity scaled by a body size-dependent power-function based on the SNR obtained with (ii). BMI, weight, body surface area, and abdominal circumference were evaluated body size parameters. Images were reconstructed with the CASToR software and evaluated for background SNR and lesion contrast-to-noise ratio (CNR). Large SNR variabilities were obtained with protocols (i) and (ii), while (iii) generated good consistency. Several tumours failed to reach a CNR of 5 for large phantoms with protocol (i), but the CNR was generally improved by (ii) and (iii). An activity scaled by patient habitus generate better image quality consistency, which increases the likelihood that patients receive a similar standard of care.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ga]Ga-DOTA-TOC, Anthropomorphic computer phantoms, Monte Carlo simulation, Positron emission tomography
in
Heliyon
volume
9
issue
9
article number
e19504
publisher
Elsevier
external identifiers
  • pmid:37681181
  • scopus:85169511011
ISSN
2405-8440
DOI
10.1016/j.heliyon.2023.e19504
language
English
LU publication?
yes
id
05acc56c-dda5-451e-a240-19d8a97fa49a
date added to LUP
2023-12-08 10:22:16
date last changed
2024-04-21 04:20:09
@article{05acc56c-dda5-451e-a240-19d8a97fa49a,
  abstract     = {{<p>One example of a PET exam that suffers from noise problems is [<sup>68</sup>Ga]Ga-DOTA-TOC, where patients are generally administered between 100 and 200 MBq [<sup>68</sup>Ga]Ga-DOTA-TOC, irrespective of size. However, a fixed activity can result in low signal-to-noise ratios (SNRs) in larger patients. This study aimed to evaluate the impact on image quality with respect to injected activity and patient habitus through Monte Carlo (MC) simulation. Eight anthropomorphic computer phantoms with body mass indices (BMIs) between 19 kg/m<sup>2</sup> and 38 kg/m<sup>2</sup> and tumours distributed in the liver were simulated using the MC software Gate v8.2 with an activity distribution defined according to [<sup>68</sup>Ga]Ga-DOTA-TOC standardised uptake values. Three activity-administration protocols were simulated: (i) with a fixed activity of 100 MBq, (ii) with the activity scaled by 2 MBq/kg, and (iii) with the activity scaled by a body size-dependent power-function based on the SNR obtained with (ii). BMI, weight, body surface area, and abdominal circumference were evaluated body size parameters. Images were reconstructed with the CASToR software and evaluated for background SNR and lesion contrast-to-noise ratio (CNR). Large SNR variabilities were obtained with protocols (i) and (ii), while (iii) generated good consistency. Several tumours failed to reach a CNR of 5 for large phantoms with protocol (i), but the CNR was generally improved by (ii) and (iii). An activity scaled by patient habitus generate better image quality consistency, which increases the likelihood that patients receive a similar standard of care.</p>}},
  author       = {{Kalaitzidis, Philip and Gustafsson, Johan and Hindorf, Cecilia and Ljungberg, Michael}},
  issn         = {{2405-8440}},
  keywords     = {{Ga]Ga-DOTA-TOC; Anthropomorphic computer phantoms; Monte Carlo simulation; Positron emission tomography}},
  language     = {{eng}},
  number       = {{9}},
  publisher    = {{Elsevier}},
  series       = {{Heliyon}},
  title        = {{Monte Carlo investigation of PET [<sup>68</sup>Ga]Ga-DOTA-TOC activity-administration protocols for consistent image quality}},
  url          = {{http://dx.doi.org/10.1016/j.heliyon.2023.e19504}},
  doi          = {{10.1016/j.heliyon.2023.e19504}},
  volume       = {{9}},
  year         = {{2023}},
}