University of Twente Student Theses
Quantitative single-photon emission computed tomography for dose calculation of radioiodine therapy in benign thyroid diseases.
Rijntjes, J. (2024) Quantitative single-photon emission computed tomography for dose calculation of radioiodine therapy in benign thyroid diseases.
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| Full Text Status: | Access to this publication is restricted |
| Embargo date: | 16 March 2026 |
| Abstract: | Introduction: Treatment of hyperthyroidism caused by Graves’ disease (GD) or toxic multinodular goiter (tMNG) is commonly performed with radioiodine (I-131) therapy, aiming to achieve permanent euthyroidism. Currently, the patient-specific required I-131 dose is calculated based on the iodine uptake and thyroid volume measured in I-123 planar scintigraphy. It is hypothesized that these measurements lack accuracy, because patients often develop life-impacting complications after I-131 therapy, such as persistent hyperthyroidism or iatrogenic hypothyroidism. Improvement of I-131 dose calculation may be a solution to reduce the incidences of hyperthyroidism and hypothyroidism after radioiodine therapy as a treatment for hyperthyroidism. This study is divided into three sections: 1) assessment of the workflow of planar scintigraphy, 2) establishment of a workflow for quantitative SPECT/CT, and 3) comparison of planar scintigraphy and quantitative SPECT/CT and evaluation of administered I-131 dose in relation to thyroid function after radioiodine therapy. Methods: For the first and second aim, a phantom study was performed to assess the current planar scintigraphy workflow and to set up a workflow for quantitative SPECT/CT for measuring the iodine uptake and thyroid volume. For the third aim, the iodine uptake, thyroid volume and calculated I-131 dose obtained with planar scintigraphy and quantitative SPECT/CT were compared in a retrospective patient study. Additionally, the administered I-131 activity concentration was estimated and evaluated in relation to the thyroid function one year after I-131 therapy. Results: Assessment of planar scintigraphy workflow resulted in several changes in the current protocol. A workflow for iodine uptake and thyroid volume measurements in quantitative SPECT/CT was successfully set up. Quantitative SPECT/CT resulted in a reduction in calculated I-131 dose as a result of higher measured iodine uptakes and more accurate thyroid volume estimations. In patients who developed hypothyroidism after I-131 therapy, the administered I-131 activity concentration was the highest compared to patients who developed euthyroidism or had persistent hyperthyroidism. Conclusion: Improved dose calculation for radioiodine therapy with quantitative SPECT/CT may be a first step towards reducing the incidence of persistent hyperthyroidism and the development of hypothyroidism after radioiodine therapy. |
| Item Type: | Essay (Master) |
| Faculty: | TNW: Science and Technology |
| Subject: | 44 medicine, 50 technical science in general |
| Programme: | Technical Medicine MSc (60033) |
| Link to this item: | https://purl.utwente.nl/essays/98492 |
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