Comparing pre-therapeutic 124I and 131I uptake tests with intra-therapeutic 131I uptake in benign thyroid disorders

Gühne, Falk; Kühnel, Christian; Freesmeyer, Martin

doi:10.1007/s12020-017-1267-8

Cited by 6 publications

(6 citation statements)

References 37 publications

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“…Similar pretherapeutic tracer studies have been reported in hyperthyroid cats 52‐54 . However, when pretherapeutic 131 I uptakes are compared to those measured after administration of therapeutic doses of 131 I, the 131 I uptake values do not always agree 49,54‐57 . One possible reason for this discrepancy is that 131 I therapy might induce early radiobiological effects, which changes the 131 I uptake and limits the usefulness of pretherapeutic dosimetry 49,55‐57 .…”

Section: Discussionmentioning

confidence: 99%

“…52 , 53 , 54 However, when pretherapeutic 131 I uptakes are compared to those measured after administration of therapeutic doses of 131 I, the 131 I uptake values do not always agree. 49 , 54 , 55 , 56 , 57 One possible reason for this discrepancy is that 131 I therapy might induce early radiobiological effects, which changes the 131 I uptake and limits the usefulness of pretherapeutic dosimetry. 49 , 55 , 56 , 57 To avoid these discrepancies, some investigators have proposed doing a 2‐step 131 I treatment in human patients, as needed based on 131 I uptakes measured after administration of an initial 131 I therapy dose.…”

Section: Discussionmentioning

confidence: 99%

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A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism

Peterson

Rishniw

2021

Veterinary Internal Medicne

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Background Radioiodine (131I) is the treatment of choice for hyperthyroidism in cats, but current 131I‐dosing protocols can induce iatrogenic hypothyroidism and expose azotemia. Objectives To develop a cat‐specific algorithm to calculate the lowest 131I dose to resolve hyperthyroidism, while minimizing risk of iatrogenic hypothyroidism and subsequent azotemia. Animals One thousand and four hundred hyperthyroid cats treated with 131I. Methods Prospective case series (before‐and‐after study). All cats had serum concentrations of thyroxine (T4), triiodothyronine (T3), and thyroid‐stimulating hormone (TSH) measured (off methimazole ≥1 week). Using thyroid scintigraphy, each cat's thyroid volume and percent uptake of 99mTc‐pertechnatate (TcTU) were determined. An initial 131I dose was calculated by averaging dose scores for T4/T3 concentrations, thyroid volume, and TcTU; 80% of that composite dose was administered. Twenty‐four hours later, percent 131I uptake was measured, and additional 131I administered, as needed, to deliver an adequate radiation dose to the thyroid tumor(s). Serum concentrations of T4, TSH, and creatinine were determined 6 to 12 months later. Results The median calculated 131I dose was 1.9 mCi (range, 1.0‐10.6 mCi); 1380 cats required additional 131I administration on day 2. Of the cats, 1047 (74.8%) became euthyroid, 57 (4.1%) became overtly hypothyroid, 240 (17.1%) became subclinically hypothyroid, and 56 (4%) remained hyperthyroid. More overtly (71.9%) and subclinically (39.6%) hypothyroid cats developed azotemia than euthyroid cats (14.2%; P < .0001). Conclusions and Clinical Importance Our algorithm for calculating individual 131I doses resulted in cure rates similar to historical treatment rates, despite much lower 131I doses. This algorithm appears to lower prevalence of both 131I‐induced overt hypothyroidism and azotemia.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism

Peterson

Rishniw

2021

Veterinary Internal Medicne

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“…Regardless of the fact that incorrectly measured values are generated by incorrect tilting of the phantoms or of the patient, the distance of 30 cm between measuring object and probe is extremely susceptible to errors. The mentioned previous study showed that these measurement errors can easily be relativized by increasing the distance [31].…”

Section: Discussionmentioning

confidence: 96%

“…We noticed measurement deviations due to patient positioning. Overflexion of the head leads to less, and overinflexion to more distance [31]. Regardless of the fact that incorrectly measured values are generated by incorrect tilting of the phantoms or of the patient, the distance of 30 cm between measuring object and probe is extremely susceptible to errors.…”

Section: Discussionmentioning

confidence: 99%

3D printing of fillable individual thyroid replicas based on nuclear medicine DICOM data used as phantoms for gamma probe calibration

et al. 2019

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Aim To proof the feasibility of manufacturing patient-indivdual (anthropomorphic) thyroid replicas from I-124 PET DICOM datasets by means of 3D printing. A possible field of application is the use of those phantoms for the calibration of gamma probes. Methods After editing of the DICOM datasets using several software types and transferring into a dedicated stereolithography format, 10 fillable thyroid replicas (35–200 mL) made of polylactide acid were manufactured via 3D printing. All replicas were filled with a water-solution containing 3.5 MBq I-131 and applied to a standard neck phantom. Calibration factor measurements were carried out using a clinical gamma probe. Measurements were performed with three different tilts: + 15°, 0° and –15°. The influence of the replicas’ volume and the tilt was investigated. Results Manufacturing of the replicas was successful in all cases. The time required for data processing was 13 ± 2 (median: 12, range: 9–25) min and 4–11 h for 3D printing (size-dependent). The printing process could be done overnight. Measured mean calibration factor for straight gamma probe positioning (0° tilt) was 31 965 ± 3360 (33 893, 25 470–34 253) cpm/MBq. A tilt of –15° resulted in lower calibration factors (–7.7 %), whereas a tilt of + 15° led to higher values (+ 9.5 %); p = 0.001. The calibration factors were highly inversely proportional correlated to the volume of the replicas (r = –0.91, p < 0.001). Conclusion 3D printing of patient-individual (anthropomorphic) fillable thyroid replicas was feasable for a large range of volumes. The study demonstrates the influence of the volume as well as the tilt of the measured object for calibration factor measurements with gamma probes.

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“…Takođe, značajan argument pobornika pristupa fiksne doze predstavlja i nepreciznost izračunate doze apsorbovanog zračenja, koja otežava korelaciju doza-efekat (6,22,33). Stvarna doza apsorbovanog zračenja koju prime tireociti nakon primjene izračunate doze aktivnosti može da se razlikuje od namjeravane (propisane) doze, što može biti posljedica primjene pojednostavljenih protokola za procjenu retencije radioaktivnog joda u štitastoj žlijezdi (17,34,35), razlika u poluvremenu eliminacije 131 I prije i tokom terapije (36,37), zatim smanjenja volumena štitaste žlijezde u toku terapije (38,39), razlika u veličini tireoidih folikula od koje zavisi izloženost tireocita zračenju (40), kao i primjena standardizovanih modela (fantoma) za procjenu E vrijednosti (33,41). Osim toga i brojni drugi faktori mogu da utiču na ishod terapije, poput individualne radiosenzitivnosti pacijenata i primjene antitireoidnih lijekova(42), što je, takođe, otežavajući faktor uspostavljanju korelacije između apsorbovane doze zračenja i efekta terapije (6).…”

Section: Doziranje Radioaktivnog Jodaunclassified

Challenges and current views on dosing of radioactive iodine in the treatment of benign thyroid disease

Topić-Vučenović¹,

Rajkovača²,

Vezmar-Kovačević³

et al. 2017

Arhiv za farmaciju

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Radioaktivni jod predstavlja značajnu terapijsku opciju u liječenju benignih oboljenja štitaste žlijezde. Uprkos višedecenijskom iskustvu i velikom broju liječenih pacijenata, mnoga pitanja vezana za terapiju radioaktivnim jodom još su uvijek predmet diskusija, uključujući način određivanja terapijske doze, kao i faktore koji utiču na ishod terapije. Klinička praksa, kao i preporuke odgovarajućih vodiča u pogledu doziranja radioaktivnog joda široko variraju u svijetu, od primjene fiksnih doza do kompleksnih dozimetrijskih protokola. Veća zastupljenost dozimetrijskog pristupa olakšala bi uspostavljanje korelacije doza-efekat i proučavanje uticaja raznih faktora na ishod terapije. Razvoj novih protokola za izračunavanje terapijske doze aktivnosti, kao i nova saznanja o faktorima koji utiču na ishod terapije omogućavaju dalje unaprijeđenje kako efikasnosti, tako i bezbjednosti terapije radioaktivnim jodom za individualnog pacijenta.

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Comparing pre-therapeutic 124I and 131I uptake tests with intra-therapeutic 131I uptake in benign thyroid disorders

Abstract: I RAIU tests represent a feasible alternative to standard I RAIU tests. The additional benefits ofI-PET/CT (e.g., functional topography, inclusion of retrosternal areas, possibility to enable fusion imaging) may thus increase the scope of this technology in benign thyroid disorders.

Cited by 6 publications

References 37 publications

A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism

A dosing algorithm for individualized radioiodine treatment of cats with hyperthyroidism

3D printing of fillable individual thyroid replicas based on nuclear medicine DICOM data used as phantoms for gamma probe calibration

Challenges and current views on dosing of radioactive iodine in the treatment of benign thyroid disease

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