Post-therapeutic Scintigraphy Research Articles

PET/CT with <sup>18</sup>F-FDG for TENIS Syndrome in a Patient with Bone Metastasis of Hurthle Cell Thyroid Cancer: a Clinical Case Report

A significant role in improving the prognosis of differentiated thyroid cancer (DTC) in the presence of bone metastases is determined by early diagnosis of metastases, timely and correctly selected treatment tactics for the patient. During dynamic follow-up of patients with DTC after combined treatment (thyroidectomy with radioiodine therapy) are determination of the level of oncomarkers (serum thyroglobulin and antibodies to thyroglobulin) and ultrasound diagnostic of the neck, scanning with radioactive iodine (if clinically indicated). In some cases, patients have TENIS-syndrome (Thyroglobulin Elevated Negative Iodine Scintigraphy, hereinafter TENIS-syndrome), characterized by high serum thyroglobulin level in blood and absence of radioactive iodine accumulation on post therapeutic scintigraphy. According to the research studies, PET/CT with 18F-FDG has high sensitivity and specificity (89 % and 72 %, respectively) in visualization of metastatic radioiodine refractory foci in TENIS-syndrome.This article presents a clinical case of a patient, a 52-year-old woman with Gurtle cell thyroid cancer (pT3aN0M0, stage I) with established TENIS syndrome. Thyroidectomy was performed in September 2019 and radioiodine therapy was performed in January 2022 due to suspected disease progression given high thyroglobulin levels. Given the absence of pathologic accumulation of 131I according to post-therapy radioiodine scanning, PET/CT with 18F-FDG was performed, which revealed a solitary metastasis in the left iliac bone (41×35×42 mm with SUVmax 17.25). In November 2022, radical treatment of the solitary bone metastasis was performed in the scope of resection of the left iliac bone with reconstructive-plastic component. According to the data of control examinations in June 2023, the patient has a complete biochemical and radiologic remission of the disease.

177Lu-DOTATATE (Lutathera) Therapy in 68Ga-DOTATATE PET/CT-Negative Liver Metastases of a Neuroendocrine Tumor.

A 73-year-old man with metastatic pancreatic neuroendocrine tumor was evaluated with 68Ga-DOTATATE PET/CT for peptide receptor radionuclide therapy. Both PET-positive and negative lesions were seen in the liver, along with extrahepatic metastases. Histopathology was obtained from one of the PET-negative liver lesions to exclude secondary malignancy. Histology confirmed a well-differentiated (G2) metastasis of pNET with high somatostatin receptor expression. We initiated peptide receptor radionuclide therapy with close monitoring of the PET-negative liver metastases. We present a rare case, where posttherapeutic scintigraphy revealed vigorous uptake of 177Lu-DOTATATE even in the 68Ga-DOTATATE PET-negative liver metastases. Follow-up PET/CT showed a partial response to therapy.

Radiosynovectomy of the hip joint - preliminary experience.

Radiosynovectomy (RSV) is a minimally invasive method of treating and controlling joint inflammation refractory to conventional pharmacotherapy. It consist in intraarticular injection of radioactive colloids which irradiate the inflamed synovial membrane to cause its subsequent involution. Despite the fact that hip joint involvement is quite common in systemic inflammatory arthropathies, hip joint RSVs are rarely performed. The aim of this paper is to assess to safety and efficacy of hip joint radioisotope treatment. We retrospectively analyzed the effects of 21 hip joint RSVs performed in 14 patients (10 female, 4 male; aged 8 to 79; mean age 48 years). Before the RSV, all the patients underwent clinical and ultrasound examination. The radiosynovectomies were performed using rhenium-186 sulfide under ultrasound guidance. Each patient underwent post-therapeutic scintigraphy to assess intraarticular distribution of the radiopharmaceutical. The effects of the treatment were assessed clinically and ultrasonographically during at least 2 follow-up visits 3 and 6 months after the RSV. In 9 cases, we observed complete resolution of symptoms 3 and 6 months after the RSV. Four patients had only a partial response and required repeated treatment, and all responded well to the second RSV. In 4 patients the treatment had no significant effect, and no repeated treatment attempt was made. All the responders suffered from inflammatory arthropathies; the non-responders had osteoarthritis, with no history of systemic diseases. In all the patients, no significant adverse effects were observed; in particular there were no radiation burns or infections. All post-therapeutic scintigrams showed proper, intraarticular distribution of the radiopharmaceutical. Radiosynovectomy of the hip joint in systemic joint diseases, especially performed using ultrasound-guidance, is a safe and effective treatment modality.

ASSESSMENT OF THE RELIABILITY OF THE CRITERIA FOR THE CONSISTENCY OF RADIOIODABLATION

Summary: the article discusses the reasons for the possible ineffectiveness of radioiodablation in patients with differentiated thyroid cancer when using adequate individually calculated activities of 131I. Based on a prospective analysis of post-therapeutic whole-body scintigraphy, laboratory parameters, dosimetric control and clinical manifestations after radionuclide therapy, significant criteria for the possible failure of standard combination therapy are identified and a change in treatment tactics in this group of patients is proposed.Purpose: search for the reasons for unsatisfactory results of radionuclide treatment in patients with differentiated thyroid cancer. Materials and Methods: analysis of 2260 patients with differentiated thyroid cancer who received combined treatment using traditional preparation methods using thyrotropin alpha, from which a group was identified with a high level of 131I. that was unexpected at the pre-therapeutic stage against the background of early radiation diseases and low dosimetry indicators. In patients, laboratory parameters of TSH, thyroglobulin and thyroglobulin antibodies were assessed using radioimmunoassay and clinical manifestations of radiation conditions, taking into account the prescribed therapy; The scintigraphy of the thyroid bed with 99mTc-pertechnetate, post-therapeutic scintigraphy with 131I upon exiting the «closed mode» and dosimetric control under standard conditions every 24 hours after taking the therapeutic activity were performed.Material and methods: prospective single-center analysis of data from 2260 patients with differentiated thyroid cancer who received combined treatment using the traditional preparation method and the use of thyrotropin alfa, from which a group with an unexpected high RP uptake at the pre-therapeutic stage was identified against the background of the absence of early radiation complications and low dosimetry indicators. In patients, laboratory parameters of TSH, TG and AT-TG were assessed using radioimmunoassay and clinical manifestations of radiation reactions, taking into account the prescribed therapy; scintigraphy of the thyroid bed with 99mТс-sodium pertechnetate, post-therapeutic scintigraphy with 131I upon exiting the «closed mode» and dosimetric monitoring with an assessment 48 hours after ingestion of therapeutic activity. Results: analyzed the data of a group of patients in whom there was a marked discrepancy between the usually interdependent results of scintigraphy before and after RIA, which subsequently changed the treatment tactics in their relation. A statistically significant difference was found between the selected groups in terms of the level of stimulated TSH (in patients with predictable (73,9±31,8 mU/L) and unexpected (114,1±30,5 mU/L) uptake of 131I (p=0,0218); by the values of the dose rate 48 hours after the intake of the calculated activity of 131I (p=0,000005). In addition, we additionally analyzed the effect of traditional and drug methods of stimulating thyrotropinemia during preparation for radionuclide ablation. Withdrawal of levothyroxine and with the use of rhTSH, TSH indices were 80,7±27 mU/L and 123,3±75,8 mU/L, respectively (p=0,035), and the levels of stimulated thyroglobulin were 10,2±4,0 ng / ml and 3,2±2,5 ng / ml (p=0,041). Conclusion: the obtained results show that the recommended empirical level of TSH > 30 mU/L is not synonymous with the activation of sodium iodine symporter and the viability of RIA, and also make it possible to distinguish a group of patients with delayed/ partial activation of the symporter. In the continuation of this study, we plan to change the protocol for preparation for radioiodablation and find criteria for pre-therapeutic diagnosis of this group of patients

Unusual Uptake of [131I] in a Tenosynovial Giant Cell Tumour Relapse in a Patient with Differentiated Thyroid Cancer.

A 77-year-old woman with follicular thyroid cancer underwent total thyroidectomy and subsequent Iodine-131 remnant ablation. She had a history of a wide tenosynovial giant cell tumor (TGCT) of the right wrist and hand that had been resected thirteen years ago. Post-therapeutic scintigraphy and single photon emission computed tomography showed mild uptake on the distal right forearm, wrist and hand. Magnetic resonance imaging and posterior histopathology confirmed a relapse of TGCT. No radioiodine adverse effects were reported after a one-year follow-up. As far as we know, this report is the first in the literature to a TGCT visualized on post-therapy radioiodine scan.

Фантомы в ядерной медицине

The nuclear medicine phantom development is based on the step by step description of the computational and experimental biological object model. Computational phantoms are used for geometry of the object description and simulate physics of particle interactions with matter, while experimental phantoms are used for quality control tests and standardization of functional research protocols. Common examples are the dosimetry planning of radionuclide therapy and post-therapeutic scintigraphy with 131I. This review provides a list of methods for computational and experimental phantoms. Examples of existing phantoms created for the nuclear medicine tasks are also given.

Abnormal Focal Jaw Uptake of 153 Sm-Ethylene-Diamine-Tetra- Methylene-Phosphonate (EDTMP) – What is the Reason?

Abnormal focal tracer uptake in the jaw during conventional bone scintigraphy is a quite frequent finding usually not related to malignant disease. In patients undergoing radionuclide therapy with lanthanoids or rhenium, the appearance is also quite frequent. ItAS¼s origin so far has not been studied in a large number of patients. Objective, to evaluate the underlying reason of abnormal focal tracer uptake in the jaw in patients who underwent 153Sm-EDTMP therapy for painful metastatic lesions. Methods, out of 138 patients, 82 revealed a positive result, 60 males and 22 females (mean age: 63.9 ± 13.9years; range 19-90 years), with metastatic bone pain were examined. Their lesions were judged by a dentist clinically and radiologically. Results, the most frequent reason of increased focal uptake in the group of mainly prostate and breast cancer patients was inflammation in 13 (24.5%) and 9 (41%) patients, respectively. In the patients below 70 years of age, inflammation was the most frequent reason with (32.7%) while in the older ones of 70 years, it was mechanically irritated by a prosthesis with (50%). In 4 of the patients, the increased uptake of 153Sm-EDTMP was due to metastatic disease as shown by PET/CT and/or MRI. Conclusion, although the number of secondary lesions in the jaw is small (4.8%), the underlying reason in conventional bone scintigraphy as well as in post-therapeutic scintigraphy should be always evaluated.

GATE based Monte Carlo simulation of planar scintigraphy to estimate the nodular dose in radioiodine therapy for autonomous thyroid adenoma

The recommended target dose in radioiodine therapy of solitary hyperfunctioning thyroid nodules is 300-400 Gy and therefore higher than in other radiotherapies. This is due to the fact that an unknown, yet significant portion of the activity is stored in extranodular areas but is neglected in the calculatory dosimetry. We investigate the feasibility of determining the ratio of nodular and extranodular activity concentrations (uptakes) from post-therapeutically acquired planar scintigrams with Monte Carlo simulations in GATE. The geometry of a gamma camera with a high energy collimator was emulated in GATE (Version 5). A geometrical thyroid-neck phantom (GP) and the ICRP reference voxel phantoms “Adult Female” (AF, 16 ml thyroid) and “Adult Male” (AM, 19 ml thyroid) were used as source regions. Nodules of 1 ml and 3 ml volume were placed in the phantoms. For each phantom and each nodule 200 scintigraphic acquisitions were simulated. Uptake ratios of nodule and rest of thyroid ranging from 1 to 20 could be created by summation. Quantitative image analysis was performed by investigating the number of simulated counts in regions of interest (ROIs). ROIs were created by perpendicular projection of the phantom onto the camera plane to avoid a user dependant bias. The ratio of count densities in ROIs over the nodule and over the contralateral lobe, which should be least affected by nodular activity, was taken to be the best available measure for the uptake ratios. However, the predefined uptake ratios are underestimated by these count density ratios: For an uptake ratio of 20 the count ratios range from 4.5 (AF, 1 ml nodule) to 15.3 (AM, 3 ml nodule). Furthermore, the contralateral ROI is more strongly affected by nodular activity than expected: For an uptake ratio of 20 between nodule and rest of thyroid up to 29% of total counts in the ROI over the contralateral lobe are caused by decays in the nodule (AF 3 ml). In the case of the 1 ml nodules this effect is smaller: 9-11% (AF) respectively 7-8% (AM). For each phantom, the dependency of count density ratios upon uptake ratios can be modeled well by both linear and quadratic regression (quadratic: r 2 > 0.99), yielding sets of parameters which in reverse allow the computation of uptake ratios (and thus dose) from count density ratios. A single regression model obtained by fitting the data of all simulations simultaneously did not provide satisfactory results except for GP, while underestimating the true uptake ratios in AF and overestimating them in AM. The scintigraphic count density ratios depend upon the uptake ratios between nodule and rest of thyroid, upon their volumes, and their respective position in a non-trivial way. Further investigations are required to derive a comprehensive rule to calculate the uptake or dose ratios based on post-therapeutic scintigraphy.

Evaluation of salivary gland function after treatment of head-and-neck tumors with intensity-modulated radiotherapy by quantitative pertechnetate scintigraphy

Purpose To evaluate salivary gland function after inversely planned stereotactic intensity-modulated radiotherapy (IMRT) for tumors of the head-and-neck region using quantitative pertechnetate scintigraphy. Methods and materials Since January 2000, 18 patients undergoing IMRT for cancer of the head and neck underwent pre- and posttherapeutic scintigraphy to examine salivary gland function. The mean dose to the primary planning target volume was 61.5 Gy (range 50.4–73.2), and the median follow-up was 23 months. In all cases, the parotid glands were directly adjacent to the planning target volume. The treatment planning goal was for at least one parotid gland to receive a mean dose of <26 Gy. Two quantitative parameters (change in maximal uptake and change in the relative excretion rate before and after IMRT) characterizing the change in salivary gland function after radiotherapy were determined. These parameters were compared with respect to the dose thresholds of 26 and 30 Gy for the mean dose. In addition, dose–response curves were calculated. Results Using IMRT, it was possible in 16 patients to reduce the dose for at least one parotid gland to ≤26 Gy. In 7 patients, protection of both parotid glands was possible. No recurrent disease adjacent to the protected parotid glands was observed. Using the Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer scoring system, only 3 patients had Grade 2 xerostomia. No greater toxicity was seen for the salivary glands. The change in the relative excretion rate was significantly greater, if the parotid glands received a mean dose of ≥26 Gy or ≥30 Gy. For the change in maximal uptake, a statistically significant difference was seen only for the parotid glands and a dose threshold of 30 Gy. For the end point of a reduction in the parotid excretion rate of >50% and 75%, the dose–response curves yielded a dose at 50% complication probability of 34.8 ± 3.6 and 40.8 ± 5.3 Gy, respectively. Conclusion Using IMRT, it is possible to protect the parotid glands and reduce the incidence and severity of xerostomia in patients. Doses <26–30 Gy significantly preserve salivary gland function. The results support the hypothesis that application of IMRT does not lead to increased local failure rates.