Indirect assessment of the maximum empirical activity (250 mCi) with respect to dosimetry concepts in radioiodine therapy of metastatic differentiated thyroid cancer

Abuqbeitah, Mohammad; Demır, Mustafa; Kabasakal, Levent; Çavdar, İkbal; Uslu-Beşli, Lebriz; Yeyin, Nami; Razavikhosroshahi, SayedBaresh; Sönmezoğlu, Kerim

doi:10.1097/mnm.0000000000000900

Cited by 9 publications

(6 citation statements)

References 16 publications

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“…Six datasets including our own cohort were used to calculate the population means and SD for whole body TIAC prepared by rhTSH and THW [23][24][25][26][27][28][29]. These parameters in patients with metastases were obtained from three datasets including our own cohort [30][31].…”

Section: Resultsmentioning

confidence: 99%

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First Strike personalized predictive radioiodine prescription for inoperable metastatic differentiated thyroid cancer

Kao

2022

Preprint

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OBJECTIVE: The traditional practice of empiric radioiodine (I-131) prescription is scientifically obsolete and inappropriate for inoperable metastatic differentiated thyroid cancer. However, theranostically guided prescription is still years away for many institutions. A personalized predictive method of radioiodine prescription that bridges the gap between empiric and theranostic methods is presented. It aims to maximize crossfire benefits within safety constraints to overcome tumour absorbed dose heterogeneity for a safe and effective first radioiodine fraction i.e., the First Strike. METHODS: The EANM method of blood dosimetry was incorporated with population kinetics, marrow and lung safety constraints, body habitus and clinical assessment of metastatic extent. Population data of whole body and blood radioiodine kinetics in patients with and without metastases, prepared by recombinant human thyroid stimulating hormone or thyroid hormone withdrawal, and the maximum safe marrow dose rate were deduced by meta-analyses of published data. For diffuse lung metastases, the lung safety limit was linearly scaled by height and separated into lung and remainder-of-body components for dosimetric consideration. RESULTS: The worst whole body Time Integrated Activity Coefficient (TIAC) of patients with metastases was 33.5 ± 17.0h and percentage of whole body TIAC attributed to blood was 16.6 ± 7.9%, prepared by thyroid hormone withdrawal. A variety of other average radioiodine kinetics are tabulated. The maximum safe marrow dose rate was deduced to be 0.265Gy/h per fraction, where blood TIAC is normalised to administered activity. An easy-to-use calculator was developed which only requires height, weight and gender to populate recommendations for personalized First Strike prescription. The treating team decides whether the prescription is to be constrained by marrow or lung, the selects an activity depending on how extensive the metastases are likely to be. A Standard Female with oligometastasis and good urine output without diffuse lung metastasis is expected to safely tolerate 217mCi (8.03GBq) of radioiodine as the First Strike. Two more examples using Standard Asian Female and Standard Male are provided.CONCLUSIONS: Our predictive method will help institutions rationalise the First Strike prescription based on radiobiologic principles, personalised to individual circumstances. Its general concept may be adapted to other forms of systemic radionuclide therapies.

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Section: Resultsmentioning

confidence: 99%

“…Population means and SD for percentage of whole body TIAC attributed to blood were calculated from two studies for both THW and rhTSH [9,23]. These parameters with metastases were obtained from data published by Abuqbeitah et al [31]. Further details of all studies are provided in Supplemental Data.…”

Section: Resultsmentioning

confidence: 99%

First Strike personalized predictive radioiodine prescription for inoperable metastatic differentiated thyroid cancer

Kao

2022

Preprint

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Section: Discussionmentioning

confidence: 99%

“…In metastatic DTC patients, the survival rate was significantly decreased and larger activity administration is more demanded [27,28]. Commonly, a single dose of 7.4 GBq is applied for metastatic DTC, while higher activity (up to 9 GBq) was administered for advanced DTC therapy [27,28]. In 2015, less intense treatment strategies for many DTC patients including observation or thyroid lobectomy without RIT were recommended by the American Thyroid Association (ATA) making controversial and significant differences in clinical practice [29,30].…”

Section: Discussionmentioning

confidence: 99%

SPECT/CT-based dosimetry of salivary glands and iodine-avid lesions following 131I therapy

et al. 2023

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ObjectiveThe purpose was to provide uptake and radiation dose estimates to salivary glands (SG) and pathologic lesions following radioiodine therapy (RIT) of differentiated thyroid cancer patients (DTC). Methods A group of DTC patients (n = 25) undergoing 131 I therapy joined this study with varying amounts of therapeutic activity. Sequential SPECT/CT scans were acquired at 4 ± 2, 24 ± 2, and 168 ± 3 h following administration of 3497-9250 MBq 131I. An earlier experiment with Acrylic glass body phantom (PET Phantom NEMA 2012 / IEC 2008) was conducted for system calibration including scatter, partial volume effect and count loss correction. Dose calculation was made via IDAC-Dose 2.1 code. ResultsThe absorbed dose to parotid glands was 0.04-0.97 Gy/GBq (median: 0.26 Gy/GBq). The median absorbed dose to submandibular glands was 0.14 Gy/GBq (0.05 to 0.56 Gy/GBq). The absorbed dose to thyroid residues was from 0.55 to 399.5 Gy/GBq (median: 21.8 Gy/GBq), and that to distal lesions ranged from 0.78 to 28.0 Gy/GBq (median: 3.12 Gy/GBq). 41% of the thyroid residues received dose > 80 Gy, 18% between 70-80 Gy, 18% between 40-70 Gy, and 23% has dose < 40 Gy. In contrast, 18% of the metastases exhibited a dose > 80 Gy, 9% between 40-60 Gy, and the dose to the vast majority of lesions (64%) was < 40 Gy. Conclusion It was inferred that dose estimation after RIT with SPECT/CT is feasible to apply, together with good agreement with published 124 I PET/CT dose estimates. A broad and sub-effective dose range was estimated for thyroid residues and distal lesions. Moreover, the current methodology might be useful for establishing a dose-effect relationship and radiationinduced salivary glands damage after RIT.

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“…analytical assessments listed in Table 3 were made based on the exponential decay of two compartments and defined as instant or slow decay terms for the numerical analysis [15][16][17][18]20]. The most intricate model of Guiu-Souto et al [19] included ten compartments and assigned two feedback paths (from body fluid to stomach and liver to body fluid), whereas others either had no assigned feedback path or defined only one feedback path.…”

Section: Plos Onementioning

confidence: 99%

Biokinetic model of radioiodine I-131 in nine thyroid cancer patients subjected to in-vivo gamma camera scanning: A simplified five-compartmental model

et al. 2020

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A five-compartmental biokinetic model of I-131 radioiodine based on in-vivo gamma camera scanning results was developed and successfully applied to nine thyroid cancer patients who were administered 1,110 MBq I-131 in capsules for the residual thyroid gland ablation. The I-131 solution activity among internal organs was analyzed via the revised biokinetic model of iodine recommended by the ICRP-30 and-56 reports. Accordingly, a five-compartmental (stomach, body fluid, thyroid, whole body, and excretion) model was established to simulate the metabolic mechanism of I-131 in thyroid cancer patients, whereas the respective four simultaneous differential equations were solved via a self-developed program run in MATLAB. This made it possible to provide a close correlation between MATLAB simulation results and empirical data. The latter data were collected through in-vivo gamma camera scans of nine patients obtained after 1, 4, 24, 48, 72, and 168 hours after radioactive I-131 administration. The average biological half-life values for the stomach, body fluid, thyroid, and whole body of thyroid cancer patients under study were 0.54±0.32, 12.6±1.8, 42.8±5.1, and 12.6±1.8 h, respectively. The corresponding branching ratios I 12 , I 23 , I 25 , I 34 , I 42 , and I 45 as denoted in the biokinetic model of iodine were 1.0, 0.21±0.14, 0.79±0.14, 1.0, 0.1, and 0.9, respectively. The average values of the AT dimensionless index used to verify the agreement between empirical and numerical simulation results were 0.056±0.017, 0.017±0.014, 0.044±0.023, and 0.045±0.009 for the stomach, thyroid, body fluid + whole body, and total, respectively. The results obtained were considered quite instrumental in the elucidation of metabolic mechanisms in the human body, particularly in thyroid cancer patients.

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Indirect assessment of the maximum empirical activity (250 mCi) with respect to dosimetry concepts in radioiodine therapy of metastatic differentiated thyroid cancer

Cited by 9 publications

References 16 publications

First Strike personalized predictive radioiodine prescription for inoperable metastatic differentiated thyroid cancer

First Strike personalized predictive radioiodine prescription for inoperable metastatic differentiated thyroid cancer

SPECT/CT-based dosimetry of salivary glands and iodine-avid lesions following 131I therapy

Biokinetic model of radioiodine I-131 in nine thyroid cancer patients subjected to in-vivo gamma camera scanning: A simplified five-compartmental model

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