[Guideline for Radioiodine Therapy for Benign Thyroid Diseases (6/2022 - AWMF No. 031-003)]. / DGN-Handlungsempfehlung (S1-Leitlinie): Radiojodtherapie bei benignen Schilddrüsenerkrankungen (Stand 6/2022 ­ AWMF-Registernummer: 031-003).

This version of the guideline for radioiodine therapy of benign thyroid disorders is an update of the version, which was published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) in co-ordination with the German Society of Endocrinology (Deutsche Gesellschaft für Endokrinologie, DGE, Sektion Schilddrüse) and the German Society of General- and Visceral-Surgery (Deutsche Gesellschaft für Allgemein- und Viszeralchirurgie, DGAV) in 2015. This guideline was harmonized with the recommendations of the European Association of Nuclear Medicine (EANM). According to the German "Directive on Radiation Protection in Medicine" the physician specialised in nuclear medicine ("Fachkunde in der Therapie mit offenen radioaktiven Stoffen") is responsible for the justification to treat with radioiodine. Therefore, relevant medical indications for radioiodine therapy and alternative therapeutic options are discussed within the guideline. This procedure guideline is developed in the consensus of an expert group. This fulfils the level S1 (first step) within the German classification of Clinical Practice Guidelines.

Focus on radioiodine-131 biokinetics: the influence of methylprednisolone on intratherapeutic effective half-life of 131I during radioiodine therapy of Graves' disease.

AIM: Radioiodine therapy (RIT) may trigger the development of Graves' ophthalmopathy (GO) or exacerbate pre-existing subclinical GO. Therefore, glucocorticoid administration is recommended for patients with pre-existing GO. Aim of this study was to analyze the influence of glucocorticoid therapy with methylprednisolone on intratherapeutic effective half-life (EHL) of radioiodine-131 in patients with Graves' disease (GD) as recent studies showed an effect for prednisolone. METHODS: In a retrospective study, 264 patients with GD who underwent RIT without any additional antithyroid medication were evaluated. Intrathyroidal EHL was determined pre- and intratherapeutically. Patients with co-existing GO (n = 43) received methylprednisolone according to a fixed scheme starting 1 day prior to RIT, patients without GO (n = 221) did not receive any protective glucocorticoid medication. The ratios of EHL during RIT and during radioiodine uptake test (RIUT) were compared. RESULTS: Patients receiving methylprednisolone showed a slight decrease of the mean EHL from 5.63 d (RIUT) to 5.39 d (RIT) (p > 0.05). A comparable result was obtained in patients without glucocorticoids (5.71 d (RIUT) to 5.47 d (RIT); p > 0.05). The ratios of the EHL between RIT and RIUT failed to show a significant difference between the two groups. EHL is therefore not significantly influenced by an additional protective treatment with methylprednisolone. CONCLUSIONS: In the present study a decreased intrathyroidal EHL under glucocorticoid medication with methylprednisolone could not be detected. Therefore, co-medication with methylprednisolone in patients with GO may be preferred to avoid an intratherapeutic decrease of EHL by accompanying protective glucocorticoides.

Correction for hyperfunctioning radiation-induced stunning (CHRIS) in benign thyroid diseases.

PURPOSE: Radioiodine-131 treatment has been a well-established therapy for benign thyroid diseases for more than 75 years. However, the physiological reasons of the so-called stunning phenomenon, defined as a reduced radioiodine uptake after previous diagnostic radioiodine administration, are still discussed controversially. In a recent study, a significant dependence of thyroid stunning on the pre-therapeutically administered radiation dose could be demonstrated in patients with goiter and multifocal autonomous nodules. A release of thyroid hormones to the blood due to radiation-induced destruction of thyroid follicles leading to a temporarily reduced cell metabolism was postulated as possible reason for this indication-specific stunning effect. Therefore, the aim of this study was to develop dose-dependent correction factors to account for stunning and thereby improve precision of radioiodine treatment in these indications. METHODS: A retrospective analysis of 313 patients (135 with goiter and 178 with multifocal autonomous nodules), who underwent radioiodine uptake testing and radioiodine treatment, was performed. The previously determined indication-specific values for stunning of 8.2% per Gray in patients with multifocal autonomous nodules and 21% per Gray in patients with goiter were used to modify the Marinelli equation by the calculation of correction factors for hyperfunctioning radiation-induced stunning (CHRIS). Subsequently, the calculation of the required activity of radioiodine-131 to obtain an intra-therapeutic target dose of 150 Gy was re-evaluated in all patients. Furthermore, a calculation of the hypothetically received target dose by using the CHRIS-calculated values was performed and compared with the received target doses. RESULTS: After integrating the previously obtained results for stunning, CHRIS-modified Marinelli equations could be developed for goiter and multifocal autonomous nodules. For patients with goiter, the mean value of administered doses calculated with CHRIS was 149 Gy and did not differ from the calculation with the conventional Marinelli equation of 152 Gy with statistical significance (p = 0.60). However, the statistical comparison revealed a highly significant improvement (p < 0.000001) of the fluctuation range of the results received with CHRIS. Similar results were obtained in the subgroup of patients with multifocal autonomous nodules. The mean value of the administered dose calculated with the conventional Marinelli equation was 131 Gy and therefore significantly below the CHRIS-calculated radiation dose of 150 Gy (p < 0.05). Again, the fluctuation range of the CHRIS-calculated radiation dose in the target volume was significantly improved compared with the conventional Marinelli equation (p < 0.000001). CONCLUSIONS: With the presented CHRIS equation it is possible to calculate a required individual stunning-independent radioiodine activity for the first time by only using data from the radioiodine uptake testing. The results of this study deepen our understanding of thyroid stunning in benign thyroid diseases and improve precision of dosimetry in radioiodine-131 therapy of goiter and multifocal autonomous nodules.

Non-Surgical and Non-Radioiodine Techniques for Ablation of Benign Thyroid Nodules: Consensus Statement and Recommendation.

Thyroid nodules and cysts are frequently diagnosed in Germany with a prevalence of about 20% in young adults reaching up to 70% in older adults. Surgery is the standard treatment of symptomatic nodules, nodules with suspicion of malignancy and thyroid cancer. Radioiodine treatment is applied for autonomously functioning nodules. During the last years new non-surgical and non-radioiodine techniques have been introduced to treat thyroid nodules. These techniques include ethanol/polidocanol treatment, radiofrequency, microwave, and laser ablation, and high frequency ultrasound ablation. A significant reduction in nodule size could be documented for these techniques in several studies, but long-term outcome data are missing. Until now, there is no general consensus regarding the appropriate indications for these methods. For this reason, the Thyroid Section (German Society for Endocrinology), the Thyroid Working Committee (German Society for Nuclear Medicine), and the German Association of Endocrine Surgeons (CAEK) for the German Society of General and Visceral Surgery (DGAV) reviewed the respective literature, discussed the pro and cons and developed a consensus statement and recommendation to help physicians and patients in their decision making.

Konversion eines postoperativen Hypoparathyreoidismus in einen Hyperparathyreoidismus bei ektopem Nebenschilddrüsenadenom.

We present a patient with a history of thyroid cancer, presumably following radiochemotherapy of a childhood medulloblastoma, who developed a primary hyperparathyroidism 10 years after long-term postsurgical hypoparathyroidism. All established imaging modalities failed to detect the origin and only selective neck sampling could identify the suspected parathyroid adenoma causing hyperparathyroidism. This encourages the use of selective neck vein catheterization, particularly in patients with only slightly elevated parathyroid hormone-levels or suspected small ectopic adenoma.

Feasibility of bipolar radiofrequency ablation in patients with parathyroid adenoma: a first evaluation.

AIM: The aim of this study was to first assess the feasibility of bipolar radiofrequency ablation in patients with parathyroid adenoma. MATERIAL AND METHODS: Bipolar RFA was performed in 9 patients with primary parathyroid adenoma in one single session. Measured parameters were PTH and calcium serum levels prior to and after bRFA. Furthermore, using an NRS pain scale (1-10), the individual, subjective maximum sensation of pain was documented. RESULTS: The bRFA resulted in a highly significant (p = .003906) decrease of serum PTH levels (median 67 ng/l) in comparison to those prior to the intervention (median 199 ng/l). Regarding calcium levels, there was no statistical significance (p = .460938), with a decrease of median serum levels comparing pre- and post-bRFA values from 2.82 mmol/l to 2.66 mmol/l. The evaluation of the individual pain sensation during the procedure was assessed by the patients with a median of 5/10 on the NRS scale. In none of the 9 cases complications such as infections, persisting pain or nerve injury occurred. CONCLUSION: For the first time, it was possible to depict the successful therapy of parathyroid adenoma by means of bRFA. This work thus proves bRFA to be an effective, safe, applicable and, concerning sensation of pain, very well tolerable thermoablative technique in the treatment of parathyroid adenoma.

Guideline Compliance in Surgery for Thyroid Nodules - A Retrospective Study.

Diagnostic guidelines for thyroid nodules focus on malignancy risk assessment to avoid unnecessary diagnostic operations. These guidelines recommend a combination of tests in form of a diagnostic algorithm. The present study analyzed the recommended algorithm and its implementation by different medical professionals. Preoperative diagnostic procedures, laboratory tests and histopathological findings of patients who underwent thyroid surgery between 2006 and 2013 were analyzed. The results were stratified by the assignation by specialized endocrinologists (ENP), general practitioners (GP) or Goethe-University Hospital Frankfurt (UKF). 677 patients were enrolled, of these 62% were assigned by UKF, 18.5% by an ENP and 19.5% by a GP. Ultrasonography rate was significantly higher in UKF (97.6%) compared to patients assigned by GP (90.9%, p<0.0001). Rates for fine-needle aspiration cytology ranged between 47.6% in UKF and 23.2% in ENP (p<0.0001). In over 93% of the patients an analysis of thyroid-stimulating hormone and triiodothyronine/thyroxin was realized. The overall malignancy rate was 11.82%. The malignancy rate was significantly higher if a FNA biopsy was performed (16.35 vs. 8.94%; p=0.0048). A higher malignancy rate could only be seen if the preoperative diagnostic workup included FNA. Besides this, the grade of algorithm adherence showed no effect on the malignancy rate.

Bipolar Radiofrequency Ablation of Benign Symptomatic Thyroid Nodules: Initial Experience.

PURPOSE: To determine the safety and efficacy of bipolar radiofrequency ablation (RFA) in benign thyroid nodules. METHODS: 23 patients with 24 symptomatic benign thyroid nodules (21 regressive, 3 adenomas) ranging in volume from 0.5 to 112 ml (mean ± sd: 18 ±â€Š24.4 ml) underwent bipolar RFA. Pain during the procedure was measured on a 10-point scale. Side-effects revealed by ultrasound or patients' complaints were documented. Periablative efficacy was measured 24 hours after RFA as change (Δ) in serum thyreoglobulin (Tg) and sonographic criteria (echogenity, Doppler blood flow and elasticity) categorized on a 3-point scale (echogenity, Doppler blood flow) or 4-point scale (elasticity). Efficacy in the 3 autonomous adenomas was measured as normalization of (99 m)Tc-pertechnate scintigraphy. RESULTS: Bipolar RFA was well tolerated by all patients with a median pain score of 3 ±â€Š1.5 (range: 1 - 7). Side-effects were hematomas in 4 of 23 patients (17 %). Bipolar RFA resulted in a significant (p < 0.01) decrease in echogenity, blood flow, elasticity (Δ = 1 ±â€Š0.28, 1 ±â€Š0.46 and 1 ±â€Š0.85 points, respectively), a median increase in Tg of 403 ±â€Š2568 ng/ml as well as in a normalization of scintigraphy. CONCLUSION: Bipolar RFA is a safe and effective treatment option for symptomatic benign thyroid nodules. KEY POINTS: • Bipolar RFA is a safe and effective treatment for benign thyroid nodules.• Ultrasound imaging allows guidance during bipolar radiofrequency ablation.• (99 m)Tc-pertechnetate is able to detect the ablation area of autonomous adenomas. Citation Format: • Korkusuz Y, Erbelding C, Kohlhase K et al. Bipolar Radiofrequency Ablation of Benign Symptomatic Thyroid Nodules: Initial experience with Bipolar Radiofrequency. Fortschr Röntgenstr 2016; 188: 671 - 675.

Localized Thyroid Tissue Ablation by High Intensity Focused Ultrasound: Volume Reduction, Effects on Thyroid Function and Immune Response.

PURPOSE: The aim of this study was to assess the effectiveness of high intensity focused ultrasound (HIFU) in reducing thyroid nodule volume while preserving thyroid function as measured by immunological response. MATERIALS AND METHODS: 12 patients (9 females) whose average age was 56.9 years (37 - 81) were treated with HIFU in an ambulatory setting. All patients had a single benign thyroid nodule treated in one HIFU session. The median nodular outline volume (NOV) was 3.4  ml (range 0.6 - 5.0  ml). The therapeutic ultrasound probe (Echopulse(®) THC900 888-H) used works with a frequency of 3  MHz, reaching temperatures of 80 - 90° C and a mean output between 87.6 and 192.8  W. To assess possible effects of HIFU on thyroid function, serum levels of triiodothyronine (T3), thyroxine (T4), thyrotropin (TSH), thyroglobulin (hTg) and antibodies against thyroglobulin (TAbs), thyrotropin receptors (TRAbs) and thyroid peroxidase (TPOAbs) were measured at enrollment, 24-hours post-HIFU treatment and at 3-month follow-up.Pre- post thyroglobulin reduction was measured to evaluate the success of ablation and the nodular outline volume (NOV) was evaluated at baseline and the 3-month follow-up to assess effectiveness. RESULTS: All measured hormone levels were within normal ranges and remained stable (p > 0.05). No clinically meaningful immune reaction was induced (p > 0.05). Thyroglobulin serum levels increased significantly at 24 hours after ablation (p < 0.05) and decreased significantly at the 3-month follow-up (p < 0.05), returning to pre-ablative levels. The median reduction in nodular outline volume (NOV) was 55 % (p < 0.05). CONCLUSION: HIFU is a safe and effective alternative for treating benign thyroid nodules, while preserving thyroid function. Further investigations with multiple treatments should be conducted to evaluate whether additional treatments can achieve greater volume reduction.

Age and body composition influence TSH concentrations after administration of rhTSH.

AIM: Previous studies listed body surface area (BSA), lean body mass (LBM), and age as modifying factors on the TSH concentrations after administration of recombinant human thyrotropin (rhTSH). The purpose of this study was to identify the main modifying factors on serum TSH levels and to compare the stimulation via single rhTSH injection after a short thyroid hormone withdrawal (THW) with that of the standard stimulating protocol. PATIENTS, METHODS: 106 patients with differentiated thyroid cancer (DTC) undergoing radioiodine therapy (RIT) after rhTSH administration were obtained through chart review. Two groups were evaluated: Group I was treated with a single rhTSH administration after two weeks of T3 therapy followed by one week of THW. Group II was stimulated according to the international standard protocol via rhTSH injections for two consecutive days. Serum TSH concentrations were documented prior to rhTSH administration (day 1 TSH), one day after (day 3 TSH) and 3-6 days after (mean 4.2 days, day 6 TSH) the last rhTSH injection. The following data was collected: age, gender, weight, height, BMI, LBM, BSA, residual thyroid tissue, CRP, creatinine, GFR, liver enzymes, alkaline phosphatase, cholesterol, and triglycerides. RESULTS: Group I: Age combined with anthropometric factors like BMI (TSH increase and day 6 TSH), BSA (TSH decrease), and gender (day 6 TSH) are the main modifying factors on serum TSH concentrations after rhTSH administration. Group II: Age and lean body mass (LBM) showed a significant impact on day 3 TSH, TSH increase (day 3-day 1), and TSH decrease (day 6-day 3). Day 6 TSH was found to be influenced by GFR (group II). CONCLUSION: Age and anthropometric parameters have significant independent influence on TSH concentrations after rhTSH injection in both groups. Anthropometric parameters (BSA, LBM) and demographic parameters (female gender) show strong influence on TSH concentrations. Further research should be conducted to examine the influence of body compartments on TSH levels through measuring total body water.

Diagnostic accuracy of elastography and scintigraphic imaging after thermal microwave ablation of thyroid nodules.

PURPOSE: The aim of this study is to evaluate structural alterations of thyroid tissue after microwave ablation using elastography and scintigraphic imaging to investigate the applicability of these diagnostic methods for follow-up.  MATERIALS AND METHODS: 35 patients with 39 thyroid nodules were evaluated using elastography and scintigraphic imaging before and after ultrasound-guided microwave ablation. Elastography was analyzed according to color-coded output and results were classified using a fourfold elasticity score (ES). Nodules color-coded blue were classified ES1 for high elasticity through ES2 and ES3 for lower elasticity, and nodules with very low elasticity were color-coded red and classified as ES4. (99m)Tc-pertechnetate served as a tracer for scintigraphic imaging of hot and indifferent nodules and (99m)Tc-MIBI for cold nodules. RESULTS: Before microwave ablation, elastography detected a median elasticity score of ES 2 ±â€Š0.7, and after ablation the median score was ES 3 ±â€Š0.6. Overall, the median score increased by 1ES ±â€Š0.6 (p < 0.01). Scintigraphic imaging detected a median reduction of tracer uptake in ablated tissue of 38.7 %±â€Š27.5(p < 0.01). (99m)Tc-pertechnetate scans showed a median decrease of tracer uptake of 26.3 %±â€Š16.3 and (99m)Tc-MIBI scans detected uptake reduction of 54.7 %±â€Š29.2. CONCLUSION: Scintigraphic imaging using (99m)Tc-pertechnetate and (99m)Tc-MIBI provides quantifiable results and is promising as a diagnostic follow-up after microwave ablation. Strain elastography detects decreasing tissue elasticity, but accuracy is limited by the necessary reduction of color-coded output to elasticity scores.

Combination of ultrasound guided percutaneous microwave ablation and radioiodine therapy in benign thyroid diseases. A suitable method to reduce the 131I activity and hospitalization time?

AIM: Goiters and thyroid nodules are an ongoing problem in healthcare. There has not been any treatment of goiters and thyroid nodules based on the combined therapy of microwave ablation (MWA) and radioiodine therapy (RIT) until now. In this study the potential benefit of a combined therapy versus single RIT is evaluated in order to achieve improvements concerning ¹³¹I-dose and hospitalization time. PATIENTS, MATERIAL, METHODS: Ten patients with goiter and benign thyroid nodules or Graves' disease were included. Pre-ablation assessments included sonographical imaging, functional imaging with 99mTc and FNAB to collect data of nodules and total thyroid volume and to exclude malignancy. Prior to treatment, radioiodine uptake test was performed. MWA was operated under local anesthesia with a system working in a wavelength field 902-928 MHz. Post-MWA, thyroid volume was recalculated ultrasonically. Due to reduced vital volume, changes of ¹³¹I-dose and hospitalization time could be monitored. RESULTS: Mean absolute thyroid volume reduction by MWA before applying RIT was 22 ± 11 ml, meaning a relative reduction of 24 ± 6% (p < 0.05). Thereby, administered activity could be reduced by 393 ± 188 MBq using the combined therapy, reflecting a relative reduction of 24 ± 6% (p < 0.05). Additionally, mean hospitalization time was decreased by 2.1 ± 0.8 days using MWA prior to RIT, implying a relative reduction of 28 ± 6% (p < 0.05). CONCLUSION: Depending on ablated volume by MWA, RIT-monotherapy requires on average 31.2% more ¹³¹I-activity than the combined therapy. The combined therapy remarkably decreases ¹³¹I-dose and hospitalization time. The combined MWA and RIT therapy is a considerable, effective and safer alternative to surgery for the treatment of very large benign nodular goiters.

Percutaneous microwave ablation of benign thyroid nodules. Functional imaging in comparison to nodular volume reduction at a 3-month follow-up.

AIM: Thyroid nodules represent a common clinical issue. Amongst other minimally invasive procedures, percutaneous microwave ablation (MWA) poses a promising new approach. The goal of this retrospective study is to find out if there is a correlation between volume reduction after 3 months and 99mTc-uptake reduction of treated thyroid nodules. PATIENTS, METHODS: 14 patients with 18 nodules were treated with MWA. Pre-ablative assessment included sonographical and functional imaging of the thyroid with 99mTc-pertechnetate and 99mTc-MIBI. Additionally, patients underwent thyroid scintigraphy 24 hours after ablation in order to evaluate the impact of the treatment on a functional level and to ensure sufficient ablation of the targeted area. At a 3-month follow-up, ultrasound examination was performed to assess nodular volume reduction. RESULTS: Mean relative nodular volume reduction after three months was 55.4 ± 17.9% (p < 0.05). 99mTc-uptake 24 hours after treatment was 45.2 ± 31.9% (99mTc-MIBI) and 35.7 ± 20.3% (99mTc-pertechnetate) lower than prior to ablation (p < 0.05). Correlating reduction of volume and 99mTc-uptake, Pearson's r was 0.41 (p < 0.05) for nodules imaged with 99mTc-MIBI and -0.98 (p < 0.05) for 99mTc-pertechnetate. According to scintigraphy 99.6 ± 22.6% of the determined target area could be successfully ablated. CONCLUSIONS: MWA can be considered as an efficient, low-risk and convenient new approach to the treatment of benign thyroid nodules. Furthermore, scintigraphy seems to serve as a potential prognostic tool for the later morphological outcome, allowing rapid evaluation of the targeted area in post-ablative examination.

Can peptide receptor radionuclide therapy be safely applied in florid bone metastases? A pilot analysis of late stage osseous involvement.

AIM: Highly advanced metastatic bone disease with extensive osseous infiltration of neuroendocrine tumours (NET) may preclude patients from treatment with peptide receptor radionuclide therapy (PRRT) in concern about haematotoxicity. This study aims to assess the safety and efficacy of PRRT with 177Lu-octreotate in a patient cohort with this condition. PATIENTS, METHODS: 41 PRRT courses were performed in 11 patients with gastroenteropancreatic neuroendocrine tumours (GEP-NET) and florid bone metastases (severely advanced widespread metastatic bone disease). A mean activity of 6.95 GBq 177Lu-octreotate was administered per treatment cycle, aimed at four courses with standard intervals of 3 months. Haematological parameters were determined prior to each treatment course, in 2-4 weeks intervals between the courses, 8-12 weeks after the last course of PRRT and in 3 monthly intervals thereafter. Toxicity was recorded using Common Terminology Criteria for Adverse Events v3.0. Restaging was performed 3 months after termination of PRRT with CT/MRI and functional imaging (modified MDA criteria). RESULTS: Significant (grade III-IV), reversible haematotoxicity occurred in 4 (35%) patients and after 10 (24%) administrations. It either resolved spontaneously (1 patient) or was controlled by supportive measures (3 patients), such as blood transfusions (3 patients) or deferral of the subsequent therapy cycle (1 patient). Patients returned to baseline blood values within up to 23 months after termination of PRRT. The observed treatment response of bone metastases consisted of a partial response in 2, a minor response in 1, stable disease in 7, and progressive disease in 1 patient. Of the 4 patients with metastatic bone pain, 1 experienced complete and 3 partial resolution of symptoms within 3-10 weeks after commencement of PRRT. CONCLUSION: These preliminary data indicate that PRRT with 177Lu-octreotate can be safely applied even in florid bone metastases with extensive, severely advanced osseous replacement. The higher myelosuppression rate was not associated with serious complications and should not preclude patients from being treated and potentially experiencing remarkable treatment efficacy despite the very advanced stage.

Percutaneous thermal microwave ablation of thyroid nodules. Preparation, feasibility, efficiency.

UNLABELLED: Microwave ablation (MWA) is a new minimal invasive method for thermal ablation of benign thyroid nodules. In contrast to well-established radiofrequency ablation (RFA), MWA offers several advantages with similarly successful results. There has not been any use of functional imaging with 99mTc-pertechnetate and 99mTc-MIBI-scans as a mere qualitative analysis of this imaging in the field of MWA in Europe until now. The aim of this study has been to demonstrate the feasibility of MWA as well as the applicability of functional imaging to verify effectiveness with a centerspecific score. PATIENTS, METHODS: 11 patients (5 women, 6 men, average age 62.3 years) with 18 benign thyroid nodules were treated. MWA was operated under local anesthesia with a system working in a wavelength field of 902 to 928 MHz (Avecure MWG881, MedWaves, Inc. San Diego, CA). Pre- and postablative scans were controlled by two specialists in nuclear medicine with longtime work experience. RESULTS: A center specific functional imaging score (CSFIS) was defined, a decrease of 1.4 points at an average was noticeable (range 1-3 points). In 66.7% (n = 12) of all nodules the score decreased by 1 point, 27.8% (n = 5) by 2 points and 5.6% (n = 1) by 3 points. The treatment was well tolerated and no severe complications were observed. CONCLUSION: The preliminary data suggests that MWA is an effective method to treat benign thyroid nodules. Functional imaging is a promising technique for early verification of effectiveness of thermal ablation.

[Perfusion brain imaging with SPECT-technique. German Guideline S1]. / Hirnperfusions-SPECT mit 99mTc-Radiopharmaka. DGN-Handlungsempfehlung (S1-Leitlinie).

This paper describes the guideline for perfusion brain imaging with SPECT-technique published by the Association of the Scientific Medical Societies in Germany (AWMF).The purpose of this guideline is to provide practical assistance for indication, examination procedures, findings and their interpretation also reflecting the present state of the art. Information and instruction are given regarding indication, preparation of the patients and examination procedures of brain perfusion SPECT, including preparation and quality control of the tracer as well as the radiation dosimetry, technical performance of image acquisition with the gamma-camera and image processing. Also advices for interpretation of findings are given. In addition, possible pitfalls are described.