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Analysis of activity uptake, effective half-life and time-integrated activity for low- and high-risk papillary thyroid cancer patients treated with 1.11 GBq and 3.7 GBq of 131I-NaI respectively

Mínguez, Pablo; Rodeño, Emilia; Genollá, José; Domínguez, Maite; Expósito, Amaia and Sjögreen Gleisner, Katarina LU (2019) In Physica Medica 65. p.143-149
Abstract

Purpose: To analyse the activity uptakes, effective half-lives and time-integrated activities, of relevance for remnant dosimetry, for patients treated for papillary thyroid cancer (PTC) with a different amount of activity of 131I-NaI. Methods: Fifty patients were included. Of those, 18 patients had low-risk PTC and were treated with 1.11 GBq of 131I-NaI (Group 1), and 32 patients had high-risk PTC and were treated with 3.7 GBq (Group 2). Radioiodine was administered after total thyroidectomy and rhTSH stimulation. Two SPECT/CT scans were performed for each patient to determine the remnant activities and effective half-lives. Results: Significantly higher values (p < 0.05) were obtained for Group 1 for the... (More)

Purpose: To analyse the activity uptakes, effective half-lives and time-integrated activities, of relevance for remnant dosimetry, for patients treated for papillary thyroid cancer (PTC) with a different amount of activity of 131I-NaI. Methods: Fifty patients were included. Of those, 18 patients had low-risk PTC and were treated with 1.11 GBq of 131I-NaI (Group 1), and 32 patients had high-risk PTC and were treated with 3.7 GBq (Group 2). Radioiodine was administered after total thyroidectomy and rhTSH stimulation. Two SPECT/CT scans were performed for each patient to determine the remnant activities and effective half-lives. Results: Significantly higher values (p < 0.05) were obtained for Group 1 for the remnant activity at 7 d (medians 1.4 MBq vs 0.27 MBq), the remnant activity per administered activity at 2 d (0.35% vs 0.09%) and at 7 d (0.13% vs 0.007%), and the effective half-life (93 h vs 40 h). Likewise, the time-integrated activity coefficient was significantly higher for Group 1. The time-integrated activity did not differ significantly between the two groups (p > 0.05). Conclusions: We found a significant difference in the remnant activity per administered activity, the rate of washout from thyroid remnants, and the time-integrated activity coefficient between low-risk PTC patients treated with 1.11 GBq and high-risk PTC patients treated with 3.7 GBq. On the contrary, there was no such difference in the time-integrated activity. If remnant masses were also not statistically different (reasonable assumption for this monocentric study) no difference in time-integrated activity would imply no difference in remnant absorbed dose, of relevance for treatment efficacy and the risks of stochastic effects.

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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
I-NaI activity, Differentiated thyroid carcinoma, Dosimetry, Pharmacokinetics, Thyroid remnants
in
Physica Medica
volume
65
pages
7 pages
publisher
ISTITUTI EDITORIALI E POLGRAFICI INTERNAZIONALI
external identifiers
  • scopus:85071388964
ISSN
1120-1797
DOI
10.1016/j.ejmp.2019.08.017
language
English
LU publication?
yes
id
5e29319b-15b8-4586-a249-b28d9900dce7
date added to LUP
2019-09-09 14:52:07
date last changed
2019-10-01 03:46:57
@article{5e29319b-15b8-4586-a249-b28d9900dce7,
  abstract     = {<p>Purpose: To analyse the activity uptakes, effective half-lives and time-integrated activities, of relevance for remnant dosimetry, for patients treated for papillary thyroid cancer (PTC) with a different amount of activity of <sup>131</sup>I-NaI. Methods: Fifty patients were included. Of those, 18 patients had low-risk PTC and were treated with 1.11 GBq of <sup>131</sup>I-NaI (Group 1), and 32 patients had high-risk PTC and were treated with 3.7 GBq (Group 2). Radioiodine was administered after total thyroidectomy and rhTSH stimulation. Two SPECT/CT scans were performed for each patient to determine the remnant activities and effective half-lives. Results: Significantly higher values (p &lt; 0.05) were obtained for Group 1 for the remnant activity at 7 d (medians 1.4 MBq vs 0.27 MBq), the remnant activity per administered activity at 2 d (0.35% vs 0.09%) and at 7 d (0.13% vs 0.007%), and the effective half-life (93 h vs 40 h). Likewise, the time-integrated activity coefficient was significantly higher for Group 1. The time-integrated activity did not differ significantly between the two groups (p &gt; 0.05). Conclusions: We found a significant difference in the remnant activity per administered activity, the rate of washout from thyroid remnants, and the time-integrated activity coefficient between low-risk PTC patients treated with 1.11 GBq and high-risk PTC patients treated with 3.7 GBq. On the contrary, there was no such difference in the time-integrated activity. If remnant masses were also not statistically different (reasonable assumption for this monocentric study) no difference in time-integrated activity would imply no difference in remnant absorbed dose, of relevance for treatment efficacy and the risks of stochastic effects.</p>},
  author       = {Mínguez, Pablo and Rodeño, Emilia and Genollá, José and Domínguez, Maite and Expósito, Amaia and Sjögreen Gleisner, Katarina},
  issn         = {1120-1797},
  keyword      = {I-NaI activity,Differentiated thyroid carcinoma,Dosimetry,Pharmacokinetics,Thyroid remnants},
  language     = {eng},
  pages        = {143--149},
  publisher    = {ISTITUTI EDITORIALI E POLGRAFICI INTERNAZIONALI},
  series       = {Physica Medica},
  title        = {Analysis of activity uptake, effective half-life and time-integrated activity for low- and high-risk papillary thyroid cancer patients treated with 1.11 GBq and 3.7 GBq of <sup>131</sup>I-NaI respectively},
  url          = {http://dx.doi.org/10.1016/j.ejmp.2019.08.017},
  volume       = {65},
  year         = {2019},
}