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SPECT/CT localization of oral radioiodine activity: a retrospective study and in-vitro assessment.

Burlison JS, Hartshorne MF, Voda AM, Cocks FH, Fair JR - Nucl Med Commun (2013)

Bottom Line: Despite subsequent washings with normal saline, significant 131I activity (maximally 12% for amalgam and 68% for Argenco HP 77) was retained by these metals.Subsequent soaking in a saturated solution of potassium iodide partially displaced 131I from amalgam, with near-total displacement of I from Argenco HP 77.Furthermore, in-vitro studies demonstrate partially reversible binding of 131I to common dental metals.

View Article: PubMed Central - PubMed

Affiliation: aDepartment of Radiology, University of New Mexico bPrivate Practice, Albuquerque, New Mexico cDepartment of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA.

ABSTRACT

Purpose: We sought to further localize radioiodine activity in the mouth on post-thyroid cancer therapy imaging using single-photon emission computed tomography/computed tomography (SPECT/CT).

Materials and methods: We retrospectively reviewed all patients (58) who underwent thyroid cancer therapy with iodine-131 (131I) at our institution from August 2009 to March 2011 whose post-therapy radioiodine imaging included neck SPECT/CT. A small group (six) of diagnostic 131I scans including SPECT/CT was also reviewed. Separately, we performed in-vitro 131I (sodium iodide) binding assays with amalgam and Argenco HP 77 (77% dental gold alloy) as proof of principle for these interactions.

Results: Of the 58 post-therapy patients, 45 (78%) had undergone metallic dental restorations, and of them 41 (91%) demonstrated oral 131I activity localizing preferentially to those restorations. It was observed that radioiodine also localized to other dental restorations and to orthodontic hardware. Gum-line activity in edentulous patients suggests radioiodine interaction with denture adhesive. In vitro, dental amalgam and Argenco HP 77 bound 131I in a time-dependent manner over 1-16 days of exposure. Despite subsequent washings with normal saline, significant 131I activity (maximally 12% for amalgam and 68% for Argenco HP 77) was retained by these metals. Subsequent soaking in a saturated solution of potassium iodide partially displaced 131I from amalgam, with near-total displacement of I from Argenco HP 77.

Conclusion: SPECT/CT shows that radioiodine in the oral cavity localizes to metallic dental restorations. Furthermore, in-vitro studies demonstrate partially reversible binding of 131I to common dental metals.

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Related in: MedlinePlus

Percentage of iodine-131 (131I) retained in Argenco HP 77 after incubating in 131I/normal saline (NS) solution and subsequent saturated solution of potassium iodide (SSKI) soak (each after multiple NS washes). The greatest amount of radioiodine retention occurs with the longest 131I/NS incubation time. Except for the 1-day 131I/NS incubation, with very little 131I retained, most radioiodine is removed by the SSKI soak.
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Figure 6: Percentage of iodine-131 (131I) retained in Argenco HP 77 after incubating in 131I/normal saline (NS) solution and subsequent saturated solution of potassium iodide (SSKI) soak (each after multiple NS washes). The greatest amount of radioiodine retention occurs with the longest 131I/NS incubation time. Except for the 1-day 131I/NS incubation, with very little 131I retained, most radioiodine is removed by the SSKI soak.

Mentions: For the Argenco HP 77 gold alloy (Fig. 6), binding likewise increased with increasing incubation time: only 1.4% of the 131I bound after 1 day, in contrast with 51 and 68% after 7 and 14 days, respectively. Even with a 2-day shorter incubation compared with the amalgam 16-day incubation samples, significantly more radioiodine bound to the Argenco HP 77 at 14 days, which was confirmed with repeated incubations. For the 1-day incubation, 3 days in SSKI displaced an additional 28% of 131I from Argenco HP 77, whereas only 1 day of SSKI soaking displaced nearly all of the remaining 131I bound to the 7- and 14-day samples. Presumably, the relatively small amount removed from the 1-day 131I incubation by the 3-day SSKI soak is attributable to the very little 131I (1.4%) that remained on the sample after NS washes.


SPECT/CT localization of oral radioiodine activity: a retrospective study and in-vitro assessment.

Burlison JS, Hartshorne MF, Voda AM, Cocks FH, Fair JR - Nucl Med Commun (2013)

Percentage of iodine-131 (131I) retained in Argenco HP 77 after incubating in 131I/normal saline (NS) solution and subsequent saturated solution of potassium iodide (SSKI) soak (each after multiple NS washes). The greatest amount of radioiodine retention occurs with the longest 131I/NS incubation time. Except for the 1-day 131I/NS incubation, with very little 131I retained, most radioiodine is removed by the SSKI soak.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815121&req=5

Figure 6: Percentage of iodine-131 (131I) retained in Argenco HP 77 after incubating in 131I/normal saline (NS) solution and subsequent saturated solution of potassium iodide (SSKI) soak (each after multiple NS washes). The greatest amount of radioiodine retention occurs with the longest 131I/NS incubation time. Except for the 1-day 131I/NS incubation, with very little 131I retained, most radioiodine is removed by the SSKI soak.
Mentions: For the Argenco HP 77 gold alloy (Fig. 6), binding likewise increased with increasing incubation time: only 1.4% of the 131I bound after 1 day, in contrast with 51 and 68% after 7 and 14 days, respectively. Even with a 2-day shorter incubation compared with the amalgam 16-day incubation samples, significantly more radioiodine bound to the Argenco HP 77 at 14 days, which was confirmed with repeated incubations. For the 1-day incubation, 3 days in SSKI displaced an additional 28% of 131I from Argenco HP 77, whereas only 1 day of SSKI soaking displaced nearly all of the remaining 131I bound to the 7- and 14-day samples. Presumably, the relatively small amount removed from the 1-day 131I incubation by the 3-day SSKI soak is attributable to the very little 131I (1.4%) that remained on the sample after NS washes.

Bottom Line: Despite subsequent washings with normal saline, significant 131I activity (maximally 12% for amalgam and 68% for Argenco HP 77) was retained by these metals.Subsequent soaking in a saturated solution of potassium iodide partially displaced 131I from amalgam, with near-total displacement of I from Argenco HP 77.Furthermore, in-vitro studies demonstrate partially reversible binding of 131I to common dental metals.

View Article: PubMed Central - PubMed

Affiliation: aDepartment of Radiology, University of New Mexico bPrivate Practice, Albuquerque, New Mexico cDepartment of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA.

ABSTRACT

Purpose: We sought to further localize radioiodine activity in the mouth on post-thyroid cancer therapy imaging using single-photon emission computed tomography/computed tomography (SPECT/CT).

Materials and methods: We retrospectively reviewed all patients (58) who underwent thyroid cancer therapy with iodine-131 (131I) at our institution from August 2009 to March 2011 whose post-therapy radioiodine imaging included neck SPECT/CT. A small group (six) of diagnostic 131I scans including SPECT/CT was also reviewed. Separately, we performed in-vitro 131I (sodium iodide) binding assays with amalgam and Argenco HP 77 (77% dental gold alloy) as proof of principle for these interactions.

Results: Of the 58 post-therapy patients, 45 (78%) had undergone metallic dental restorations, and of them 41 (91%) demonstrated oral 131I activity localizing preferentially to those restorations. It was observed that radioiodine also localized to other dental restorations and to orthodontic hardware. Gum-line activity in edentulous patients suggests radioiodine interaction with denture adhesive. In vitro, dental amalgam and Argenco HP 77 bound 131I in a time-dependent manner over 1-16 days of exposure. Despite subsequent washings with normal saline, significant 131I activity (maximally 12% for amalgam and 68% for Argenco HP 77) was retained by these metals. Subsequent soaking in a saturated solution of potassium iodide partially displaced 131I from amalgam, with near-total displacement of I from Argenco HP 77.

Conclusion: SPECT/CT shows that radioiodine in the oral cavity localizes to metallic dental restorations. Furthermore, in-vitro studies demonstrate partially reversible binding of 131I to common dental metals.

Show MeSH
Related in: MedlinePlus