The rational use of201Tl scintigraphy in the evaluation of differentiated thyroid cancer

Nĕmec, J; Zamrazil, V; Pohunková, D; Röhling, S; Holub, V

doi:10.1007/bf00803247

Cited by 19 publications

(5 citation statements)

References 14 publications

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“…The activity administered prior to radioiodine imaging influences the detection sensitivity of the diagnostic procedure. This subjectively plausible assumption was empirically proven in studies comparing images of patients who underwent dxWBS and shortly afterwards received therapy with subsequent rxWBS (Nemec et al 1979, Coakley et al 1980, Pacini et al 1987, de Keizer et al 2001, Koh et al 2003. Figure 5 shows an example comparing a scan two days after the administration of a diagnostic activity of 10 MBq 131 I (figure 5(a)) and a scan seven days after the subsequent therapy with 17.3 GBq (figure 5(b)) in the same patient.…”

Section: Discussionmentioning

confidence: 96%

The limit of detection in scintigraphic imaging with I-131 in patients with differentiated thyroid carcinoma

et al. 2014

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Radioiodine scintigraphy influences staging and treatment in patients with differentiated thyroid carcinoma. The limit of detection for fractional uptake in an iodine avid focus in a scintigraphic image was determined from the number of lesion net counts and the count density of the tissue background. The count statistics were used to calculate the diagnostic activity required to elevate the signal from a lesion with a given uptake significantly above a homogeneous background with randomly distributed counts per area. The dependences of the minimal uptake and the minimal size of lesions visible in a scan on several parameters of influence were determined by linking the typical biokinetics observed in iodine avid tissue to the lesion mass and to the absorbed dose received in a radioiodine therapy. The detection limits for fractional uptake in a neck lesion of a typical patient are about 0.001% after therapy with 7000 MBq, 0.01% for activities typically administered in diagnostic assessments (74-185 MBq), and 0.1% after the administration of 10 MBq I-131. Lesions at the limit of detection in a diagnostic scan with biokinetics eligible for radioiodine therapy are small with diameters of a few millimeters. Increasing the diagnostic activity by a factor of 4 reduces the diameter of visible lesions by 25% or about 1 mm. Several other determinants have a comparable or higher influence on the limit of detection than the administered activity; most important are the biokinetics in both blood pool and target tissue and the time of measurement. A generally valid recommendation for the timing of the scan is impossible as the time of the highest probability to detect iodine avid tissue depends on the administered activity as well as on the biokinetics in the lesion and background in the individual patient.

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Section: Discussionmentioning

confidence: 96%

The limit of detection in scintigraphic imaging with I-131 in patients with differentiated thyroid carcinoma

et al. 2014

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“…Thallium is taken up by cells by the same mechanism as is potassium. Initial studies involving small numbers of cases indicated that 201 ji yielded high sensitivity for thyroid carcinoma metastases (34,35). The largest study was that of Hoefnagel and co-workers (36), who reviewed retrospectively experience with 201T1 and 131I scanning in 301 patients with differentiated thyroid carcinoma.…”

Section: Radiopharmaceuticals Other Than Radioiodinementioning

confidence: 98%

Nuclear Imaging in the Management of Thyroid Carcinoma

Cavalieri¹

1996

Thyroid

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The avidity of differentiated thyroid carcinoma for iodine is the basis for the use of radioiodine (131I) both for the detection and the treatment of recurrent thyroid cancer in patients following initial surgical treatment (thyroidectomy). Because recurrence of this type of cancer may be delayed for many years, long-term follow-up is needed. Nowadays such surveillance involves clinical assessment, monitoring of serum thyroglubulin, and, when indicated, whole-body imaging with 131I. Sensitivity of 131I imaging depends on proper preparation of the patient and careful attention to imaging technique. Interpretation of images requires knowledge of physiologic sites of radioiodine concentration and causes of artifacts. Because of the potential suppressive effect of the radiation from a diagnostic administration of 131I on the uptake of a subsequent therapeutic administration (so-called stunning of thyroid tissue) many centers limit the amount given for scanning to 2-3 mCi (74-111 MBq). Several tumor-seeking radioisotopic agents other than radioiodine have shown promise for improving the detection of metastases, and some of these agents offer a useful adjunct to 131I in the management of selected patients, particularly in those with suspected metastatic disease and negative 131I scans.

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“…Dx WBI is usually performed using the low activity of I-131, 37-185 MBq (1-5 mCi), which has low sensitivity for the detection of occult disease [5]. In contrast, a higher amount of I-131 activity increases lesion detection and sensitivity [6][7][8][9] but may produce thyroid stunning. Stunning phenomenon decreases the uptake of the therapeutic dose [10][11][12][13], impairing the efficacy of radioiodine treatment [14][15][16][17].…”

Section: Pre-treatment Whole-body Imagingmentioning

confidence: 99%

Pre-Treatment and Post-Treatment I-131 Imaging in Differentiated Thyroid Carcinoma

Mihailović

2024

JCM

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Radioiodine imaging in initial perioperative settings, after the total thyroidectomy, includes pre-treatment and post-treatment radioiodine imaging. While the benefit of post-treatment whole-body imaging (PT-WBI) is well established, the role of diagnostic whole-body imaging (dx WBI), prior to radioiodine (I-131) ablative or therapeutic doses, is controversial. Dx WBI has been abandoned in most nuclear medicine centers long ago. Planar low-dose dxWBI provides the volume of postoperative thyroid remnants, but it cannot detect occult metastatic foci in the neck. The modern integrated multimodality, i.e., SPECT/CT imaging, provides three dimensional images and accurate anatomic/metabolic data. This hybrid technology offers better spatial resolution but not better sensitivity. Dx WBI has low theranostic power because of the radioiodine indifference and low detection sensitivity for small-volume nodal disease in the neck. Since dx WBI cannot clarify the paratracheal cervical uptake, thyroid remnants may be easily misinterpreted as nodal disease, leading to a false N upstaging (from N0 stage to N1 stage) in DTC patients. Post-ablation I-131 imaging has a significant role in the initial staging of radioiodine-avid DTC and in the identification of non-radioiodine avid tumors. Additionally, SPECT/CT in the post-treatment setting provides more accurate initial TNM staging and better risk stratification of DTC patients. Post-treatment I-131 imaging is obligatory and must be performed in all DTC patients who receive radioiodine treatment.

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The rational use of201Tl scintigraphy in the evaluation of differentiated thyroid cancer

Cited by 19 publications

References 14 publications

The limit of detection in scintigraphic imaging with I-131 in patients with differentiated thyroid carcinoma

The limit of detection in scintigraphic imaging with I-131 in patients with differentiated thyroid carcinoma

Nuclear Imaging in the Management of Thyroid Carcinoma

Pre-Treatment and Post-Treatment I-131 Imaging in Differentiated Thyroid Carcinoma

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