See the published version of this preprint at EJNMMI Physics.
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Original research
Martina Stella
Universitair Medisch Centrum Utrecht
Corresponding Author
ORCiD: https://orcid.org/0000-0001-9794-3184
License:
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Purpose: Accurate dosimetry is essential in radioembolization. To this purpose, an automatic protocol for healthy liver dosimetry based on dual isotope (DI) SPECT imaging, combining holmium-166 (166Ho)-microspheres and technetium-99m (99mTc)-colloid, was developed: 166Ho-microspheres used as scout and therapeutic particles and 99mTc-colloid to identify the healthy liver. DI SPECT allows for an automatic and accurate estimation of absorbed doses, introducing true personalized dosimetry. However, photon crosstalk between isotopes can compromise image quality. This study investigates the effect of 99mTc downscatter on 166Ho dosimetry, by comparing 166Ho-SPECT reconstructions of patient scans acquired before (166Ho-only) and after additional administration of 99mTc-colloid (166Ho-DI).
Methods: The 166Ho-only and 166Ho-DI scans were performed in short succession by injecting 99mTc-colloid on the scanner table. To compensate for 99mTc downscatter, its influence was accounted for in the DI image reconstruction using energy window-based scatter correction methods. The qualitative assessment was performed by independent blinded comparison by two nuclear medicine physicians assessing 65 pairs of SPECT/CT. Inter-observer agreement was tested by Cohen's kappa coefficient. For the quantitative analysis, two volumes of interest within the liver, VOITUMOR and VOIHEALTHY, were manually delineated on the 166Ho-only reconstruction and transferred to the co-registered 166Ho-DI reconstruction. Absorbed dose within the resulting VOIs, and in the lungs (VOILUNGS), was calculated based on the administered therapeutic activity.
Results: The qualitative assessment showed no distinct clinical preference for either 166Ho-only or 166Ho-DI SPECT (kappa=0.093). Quantitative analysis indicated that the mean absorbed dose difference between 166Ho-DI and 166Ho-only was -2.00±2.84 Gy (median 27 Gy; p-value<0.00001), -5.27±8.99 Gy (median 116 Gy; p-value =0.00035) and 0.80±1.08 Gy (median 3 Gy; p-value<0.00001) for VOIHEALTHY, VOITUMOR and VOILUNGS respectively. The corresponding Pearson’s correlation coefficient between 166Ho-only and 166Ho-DI for absorbed dose was 0.97, 0.99 and 0.82, respectively.
Keywords
Radioembolization – Holmium-166 – SPECT/CT – Dual Isotope – Technetium – Scatter Correction
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View the published article at EJNMMI Physics.
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Editorial decision: Accept
On 02 Jul, 2020
Review #2 received
Received 30 Jun, 2020
Reviewer #2 agreed
On 25 Jun, 2020
Review #1 received
Received 21 Jun, 2020
Editor assigned
On 10 Jun, 2020
Reviewers invited
Invitations sent on 10 Jun, 2020
Reviewer #1 agreed
On 10 Jun, 2020
Submission checks complete
On 09 Jun, 2020
Editor invited
On 09 Jun, 2020
No comments provided
Editorial decision: Minor Revision
On 29 May, 2020
Review #2 received
Received 25 May, 2020
Reviewer #3 agreed
On 22 May, 2020
Review #1 received
Received 10 May, 2020
Reviewer #2 agreed
On 22 Apr, 2020
Reviewers invited
Invitations sent on 21 Apr, 2020
Reviewer #1 agreed
On 21 Apr, 2020
Editor assigned
On 07 Apr, 2020
Editor invited
On 06 Apr, 2020
Submission checks complete
On 03 Apr, 2020
First submitted
On 02 Apr, 2020
Metrics
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PDF Downloads: ...
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Subject Areas
Biophysics
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See the published version of this preprint at EJNMMI Physics.
This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Original research
Martina Stella
Universitair Medisch Centrum Utrecht
Corresponding Author
ORCiD: https://orcid.org/0000-0001-9794-3184
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
View the published article at EJNMMI Physics.
Version 2
Posted 15 Jun, 2020
No community comments so far
Editorial decision: Accept
On 02 Jul, 2020
Review #2 received
Received 30 Jun, 2020
Reviewer #2 agreed
On 25 Jun, 2020
Review #1 received
Received 21 Jun, 2020
Editor assigned
On 10 Jun, 2020
Reviewers invited
Invitations sent on 10 Jun, 2020
Reviewer #1 agreed
On 10 Jun, 2020
Submission checks complete
On 09 Jun, 2020
Editor invited
On 09 Jun, 2020
No comments provided
Editorial decision: Minor Revision
On 29 May, 2020
Review #2 received
Received 25 May, 2020
Reviewer #3 agreed
On 22 May, 2020
Review #1 received
Received 10 May, 2020
Reviewer #2 agreed
On 22 Apr, 2020
Reviewers invited
Invitations sent on 21 Apr, 2020
Reviewer #1 agreed
On 21 Apr, 2020
Editor assigned
On 07 Apr, 2020
Editor invited
On 06 Apr, 2020
Submission checks complete
On 03 Apr, 2020
First submitted
On 02 Apr, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Biophysics
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published article at EJNMMI Physics.
Purpose: Accurate dosimetry is essential in radioembolization. To this purpose, an automatic protocol for healthy liver dosimetry based on dual isotope (DI) SPECT imaging, combining holmium-166 (166Ho)-microspheres and technetium-99m (99mTc)-colloid, was developed: 166Ho-microspheres used as scout and therapeutic particles and 99mTc-colloid to identify the healthy liver. DI SPECT allows for an automatic and accurate estimation of absorbed doses, introducing true personalized dosimetry. However, photon crosstalk between isotopes can compromise image quality. This study investigates the effect of 99mTc downscatter on 166Ho dosimetry, by comparing 166Ho-SPECT reconstructions of patient scans acquired before (166Ho-only) and after additional administration of 99mTc-colloid (166Ho-DI).
Methods: The 166Ho-only and 166Ho-DI scans were performed in short succession by injecting 99mTc-colloid on the scanner table. To compensate for 99mTc downscatter, its influence was accounted for in the DI image reconstruction using energy window-based scatter correction methods. The qualitative assessment was performed by independent blinded comparison by two nuclear medicine physicians assessing 65 pairs of SPECT/CT. Inter-observer agreement was tested by Cohen's kappa coefficient. For the quantitative analysis, two volumes of interest within the liver, VOITUMOR and VOIHEALTHY, were manually delineated on the 166Ho-only reconstruction and transferred to the co-registered 166Ho-DI reconstruction. Absorbed dose within the resulting VOIs, and in the lungs (VOILUNGS), was calculated based on the administered therapeutic activity.
Results: The qualitative assessment showed no distinct clinical preference for either 166Ho-only or 166Ho-DI SPECT (kappa=0.093). Quantitative analysis indicated that the mean absorbed dose difference between 166Ho-DI and 166Ho-only was -2.00±2.84 Gy (median 27 Gy; p-value<0.00001), -5.27±8.99 Gy (median 116 Gy; p-value =0.00035) and 0.80±1.08 Gy (median 3 Gy; p-value<0.00001) for VOIHEALTHY, VOITUMOR and VOILUNGS respectively. The corresponding Pearson’s correlation coefficient between 166Ho-only and 166Ho-DI for absorbed dose was 0.97, 0.99 and 0.82, respectively.
Figure 1
Figure 2
Figure 3
Figure 4
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