Body Scintigraphy Research Articles

Software-assisted dosimetry in peptide receptor radionuclide therapy with 177Lutetium-DOTATATE for various imaging scenarios.

In peptide receptor radionuclide therapy (PRRT) of patients with neuroendocrine neoplasias (NENs), intratherapeutic dosimetry is mandatory for organs at risk (e.g. kidneys) and tumours. We evaluated commercial dosimetry software (Dosimetry Toolkit) using varying imaging scenarios, based on planar and/or tomographic data, regarding the differences in calculated organ/tumour doses and the use for clinical routines. A total of 16 consecutive patients with NENs treated by PRRT with 177Lu-DOTATATE were retrospectively analysed. Single-photon emission computed tomography (SPECT)/low-dose computed tomography (CT) of the thorax and abdomen and whole body (WB) scintigraphy were acquired up to 7 days p.i. (at a maximum of five imaging time points). Different dosimetric scenarios were evaluated: (1) a multi-SPECT-CT scenario using SPECT/CT only; (2) a planar scenario using WB scintigraphy only; and (3) a hybrid scenario using WB scintigraphy in combination with a single SPECT/low-dose CT. Absorbed doses for the kidneys, liver, spleen, lungs, bladder wall and tumours were calculated and compared for the three different scenarios. The mean absorbed dose for the kidneys estimated by the multi-SPECT-CT, the planar and the hybrid scenario was 0.5 ± 0.2 Sv GBq-1, 0.8 ± 0.4 Sv GBq-1 and 0.6 ± 0.3 Sv GBq-1, respectively. The absorbed dose for the residual organs was estimated higher by the planar scenario compared to the multi-SPECT-CT or hybrid scenario. The mean absorbed tumour doses were 2.6 ± 1.5 Gy GBq-1 for the multi-SPECT-CT, 3.1 ± 2.2 Gy GBq-1 for the hybrid scenario and 5.3 ± 6.3 Gy GBq-1 for the planar scenario. SPECT-based dosimetry methods determined significantly lower kidney doses than the WB scintigraphy-based method. Dosimetry based completely on SPECT data is time-consuming and tedious. Approaches combining SPECT/CT and WB scintigraphy have the potential to ensure compromise between accuracy and user-friendliness.

Incidental Tc-99m Methylene Diphosphonate Uptake in an Active Thyroid Nodule.

Tc-99m-methylene diphosphonate (MDP) whole body scintigraphy is the method of choice for detection of metastatic bone diseases. It is primarily used to help diagnose various bone-related conditions such as primary or metastatic cancer of the bone, location of bone inflammation, and fractures that may not be visible on traditional X-ray images, as well as detection of bone damage due to infections and other conditions. In addition, bone scanning is often used for the follow-up or evaluation of response to treatment in some malignancies like prostate and breast cancers. Pathologies of other systems can also be incidentally detected on whole body bone scan. Herein we present an interesting image of an active thyroid nodule that showed Tc-99m MDP uptake in a prostate cancer patient.

Diagnostic Performance of 18F-FDG PET/CT in Papillary Thyroid Carcinoma with Negative 131I-WBS at first Postablation, Negative Tg and Progressively Increased TgAb Level

Differentiated thyroid cancer (DTC) patients with negative serum thyroglobulin (Tg), negative 131I whole–body scintigraphy (131I-WBS) at first post-ablation and progressively increased TgAb level are a relatively rare entity in the follow-up after total thyroidectomy and radioactive iodine therapy. The value of 18F-FDG PET/CT in detecting the recurrence of disease in these patients has only been reported in a small case series. The goal of this study was to investigate the diagnostic accuracy of 18F-FDG PET/CT in detecting recurrent disease in these specific PTC patients and to identify risk factors for patients with positive 18F-FDG PET/CT results. Eighty-two PTC patients who had 18F-FDG PET/CT scans with negative Tg, negative 131I-WBS at first post-ablation and progressively increased TgAb levels were included. We found that the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 18F-FDG PET/CT in this patient group were determined as 84%, 72%, 92%, 57% and 82%, respectively. 18F-FDG PET/CT scan had a good diagnostic performance and should be performed routinely in PTC patients with negative Tg, negative 131I-WBS at first postablation and progressively increased TgAb level, especially when span for progressively increased TgAb level ≥ 3 years and/or progressively increased TgAb value up to 150 IU/mL.

Typographical Errors in Article Entitled, "Unusual False Positive Radioiodine Uptake on 131I Whole Body Scintigraphy in Three Unrelated Organs with Different Pathologies in Patients of Differentiated Thyroid Carcinoma: A Case Series."

Typographical Errors in Article Entitled, "Unusual False Positive Radioiodine Uptake on 131I Whole Body Scintigraphy in Three Unrelated Organs with Different Pathologies in Patients of Differentiated Thyroid Carcinoma: A Case Series."

Iodine-131 Therapy and Lacrimal Drainage System Toxicity: Nasal Localization Studies Using Whole Body Nuclear Scintigraphy and SPECT-CT.

The objective of this study was to evaluate the influence of dose on nasal localization of radioactive iodine-131 (I-131) following therapy for differentiated thyroid carcinomas. Retrospective evaluation of all patients who underwent post-therapy I-131 whole body scintigraphy and single photon emission computed tomography was performed. Patients were divided into 2 groups; group A were treated with 100 millicurie (mCi) and group B with ≥150 mCi. Databases were reviewed for demographics, diagnosis, and administered dosage of I-131. Whole body scintigraphy images were retrieved and nasal uptake was analyzed and classified as nil to trace, low, moderate, and high uptake and corresponding single photon emission CTs were analyzed for radioactive nasal activity. A total of 100 patients were studied, 50 in each of the groups. The M:F ratio was 1.1:1 (27:23) in group A and 1.5:1 (30:20) in group B. The mean age was 43.12 years and 54.6 years in groups A and B, respectively. Papillary carcinoma of the thyroid was the most common type accounting for 82% (41/50) of patients in group A and 62% (31/50) in group B. Imaging studies revealed nil to trace nasal activity in 80% (40/50) in group A as compared with 56% (28/50) in group B. None of the patients in group A showed high nasal uptake, whereas 4% (2/50) in group B demonstrated such high activity. Intranasal localization of radioactive I-131 was significant in patients receiving a dose of ≥150 mCi. Intranasal localization may partly explain toxicity to nasolacrimal duct and may be a risk factor for subsequent development of nasolacrimal duct obstructions.

18F-FDG Pet-Guided External Beam Radiotherapy in Iodine-Refractory Differentiated Thyroid Cancer: A Pilot Study.

Introduction To evaluate the clinical response rate after a postoperative 18F-FDG PET/CT guided external beam radiotherapy (EBRT) in Iodine-refractory differentiated thyroid cancer. Material and Methods Patients with thyroid cancer locally recurrent after total thyroidectomy plus metabolic radiotherapy and treated with radical EBRT were included. Inclusion criteria were detectable thyroglobulin (Tg), negative postmetabolic radiotherapy whole body scintigraphy, and no surgical indications. The pretreatment 18F-FDG PET/CT resulted positive in all cases (loggia, lymph nodes, and lung). EBRT was delivered with IMRT-SIB technique. A 18F-FDG PET/CT revaluation and Tg dosage were performed 3 months after the treatment. Results Sixteen consecutive patients were included in this analysis (median follow-up: 6–44 months). Post-EBRT 18F-FDG PET/CT showed CR in 43.7%, PR in 31.2%, SD in 25.0% patients, and PD due to lung metastases in 12.5%. Overall response rate was 75.0% (CI 95%: 41.4–93.3%). Tg levels decreased in 75.0% with a median Δ of 68.0%. Two-year PFS and OS rates were 80.0% and 93.0%, respectively. Acute G3 toxicity occurred in 18.7% and late G2 toxicity in 12.5%. Conclusions 18F-FDG PET/CT was useful in target definition for radiotherapy planning, identifying positive areas not detected with 131I scintigraphy. IMRT based EBRT was feasible and our results encourage future prospective studies. This clinical trial is registered with ID: NCT03191643.

Radiolabeled tirofiban - a potential radiopharmaceutical for detection of deep venous thrombosis.

AimThe aim of this study was to investigate the possibility of using 99mtechnetium (99mTc)-labeled tirofiban (a reversible antagonist of glycoprotein IIb/IIIa) for detection of deep venous thrombosis (DVT) in rats without causing an antiplatelet effect.MethodsThe ability of in vitro tirofiban to inhibit adenosine 5′-diphosphate (ADP)-induced platelet aggregation was evaluated using optical aggregometer. Binding of 99mTc-tirofiban to platelets was evaluated. Serum levels of unlabeled (a validated high performance liquid chromatography method) and 99mTc-tirofiban after single intravenous injection were evaluated in male Wistar rats with or without induced DVT (femoral vein ligation model), and the rats were also subjected to whole body scintigraphy.ResultsTirofiban in vitro inhibits ADP-induced aggregation of human platelets in a dose- and concentration-dependent manner (10 nM to 2 μM), but only if it is added before ADP and not after ADP. 99mTc labeling did not affect the ability of tirofiban to bind to either human or rat platelets, nor did it affect tirofiban pharmacokinetics in intact rats or in animals with induced DVT. When 99mTc-tirofiban was injected to rats after induction of DVT, at a molar dose lower than the one showing only a weak antiaggregatory effect in vitro, whole body scintigraphy indicated localization of 99mTc-tirofiban around the place of the induced DVT.Conclusion99mTc labeling of tirofiban does not affect its ability to bind to glycoprotein IIb/IIIa or its in vivo pharmacokinetics in rats, either intact or with DVT. A low, nonantiaggregatory dose of 99mTc-tirofiban may be used to visualize DVT at an early stage.

99mTc-EDDA/HYNIC-TOC in the diagnosis of differentiated thyroid carcinoma refractory to radioiodine treatment.

In majority of cases of differentiated thyroid carcinoma (DTC), the ablative radioiodine treatment shows high efficacy. In a small number of patients, mechanism of selective iodine uptake by the DTC cells is insufficient and alternative methods of diagnosis and treatment are needed. As demonstrated in vitro, DTC cells show expression of somatostatin recep-tors. Radiolabeled somatostatin analogs are widely used in the diagnosis of neuroendocrine tumors. The aim of the study was to evaluate the utility of peptide receptor scintigraphy with the use of 99mTc-EDDA/HYNIC-TOC in the diagnosis of DTC in patients with elevated thyroglobulin concentrations (Tg), negative WBS and no effect of the consecutive radioiodine therapies. Whole body scintigraphy as well as SPECT of neck and chest were performed 3 and 24 h after i.v. administration of 740 MBq 99mTc-EDDA/HYNIC-TOC. The obtained images were compared with other radionuclide and ra-diological imaging methods. Forty-three patients with DTC after surgery and ablative radioiodine treatment with negative WBS and elevated Tg were qualified. Patients' age: 18-83 years (mean 58.0). SRS showed foci of tracer accumulation in 29 cases (67.4%). Sensitivity was 69.0% specificity 78.6%. SRS correctly identified local recurrence in 8 pts., metastatic lymph nodes in 19 pts., lung metastases in 12 pts. and bone metastases in 5 pts. SRS showed high sensitivity in the detection of metastatic lymph nodes (100%) and bone metastases (83.3%) and lung metastases (63.2%). Positive SRS was found in pts. with higher Tg concentrations (130 ± 144 vs. 30 ± 54 ng/ml). Scintigraphy with the use of the studied technetium-99m-labeled somatostatin analog is useful in the evaluation of patients with advanced DTC. It shows relatively good sensitivity and specificity but not high enough to be recommended as a routine imaging method. The role of somatostatin receptor scintigraphy in DTC is complementary to other imaging modalities.

A Case of Second Primary Multiple Myeloma Mimicking Bone Metastases in a Patient with Breast Cancer: An Approach to Osseous Metastases

A 62-year-old female patient received adjuvant chemotherapy after a mastectomy due to a locally advanced invasive ductal carcinoma eight years ago. During the follow-up, she complained of extensive backache, so a plain radiography was taken. The radiography showed diffuse lytic lesions located primarily around the vertebrae and sternum. Given that the bone lesions could be related to osseous metastases of the breast cancer, a bone scintigraphy was performed and no positive involvement was observed. Magnetic resonance imaging was subsequently applied and diffuse hypointense areas were found on the vertebrae. The patient had also accompanying bicytopenia (thrombocytopenia and luecocytopenia), albumin/globulin inversion and hyperglobulinemia. As the patient did not have such involvement in regard to her overall body scintigraphy and there were accompanying abnormal biochemical parameters, it was concluded that the patient’s bone lesions were an outcome of a hematological malignity. Bone marrow aspiration and the biopsy result were found to be consistent with multiple myeloma (MM). It was thus confirmed that the lytic lesions were not related to breast cancer but rather MM bone lesions. We are able to conclude, based on the case presented herein, that newly-developing bone lesions on patients with breast cancer must be approached with suspicion, and their other laboratory analyses and imaging diagnostic processes must be evaluated carefully. It is necessary to keep in mind that such a condition might be related to other diseases, however rare the occurrence.

99m Tc–MDP Bone Scan in Lung Cancer: Predilection Sites for Metastasis

Introduction: Bone scan with 99m Tc-MDP is a commonly used procedure for evaluation of bone metastases because of its high sensitivity, availability, and relatively low cost. The predilection sites for bone metastasis in patients particularly with lung cancers were investigated in this study.Methods: The study was done at the National Institute of Nuclear Medicine and Allied Sciences (NINMAS) between January 2013 and June 2014. A total of 123 patients with lung cancers who had whole body scintigraphy with 99mTc-MDP were studied. The bone scans were interpreted by experienced Nuclear Medicine physicians and the predilection sites with pattern of skeletal metastasis were analyzed.Results: Among the 123 (m/f: 104/19) cases studied, 99 (80.5%) patients had bone metastasis. Solitary metastatic lesion was detected in 18.2% cases, multiple lesions in 59.6% cases and extensive metastases were noted in 18.2% cases. Features of hypertrophic pulmonary osteoarthopathy were present in 4% cases. The predilection sites for metastases from lung cancer appear to be in the ribs (75% cases) followed by spines (54% cases) and pelvis (23% cases). In total 595 metastatic lesions were detected, among them 469(78.8%) were distributed in axial skeleton and 126 (21.2%) were in appendicular skeleton. Metastatic involvement was higher in axial skeleton comparing to the appendicular skeleton and the difference was statistically significant (Z=13.99, P<0.001). Similarly metastatic lesions detected on right side of body were 235 in number and on left side of the body were 189 in number. This difference of distribution between right and left side was also found to be statistically significant (Z=2.218, p<0.002).Conclusion: Bone metastasis is very common in patients with lung cancer. The predilection site for metastasis was the axial skeleton, which had statistically higher involvement than appendicular skeleton. Distributions of metastatic bone lesions were higher in ribs followed by vertebrae and pelvis. Significant difference was observed in the distribution of metastasis between the right and left side of body.Bangladesh J. Nuclear Med. 17(2): 120-124, July 2014

Preclinical evaluation of 99mTc labeled chondroitin sulfate for monitoring of cartilage degeneration in osteoarthritis

PurposeIn previous in-vitro and ex-vivo studies we proved the specific uptake of 99mTc radiolabeled chondroitin sulfate (CS) in human articular cartilage. As a logical next step for the clinical use for imaging osteoarthritis we investigated in-vivo uptake of 99mTcCS in dogs. ProceduresThe radiolabeling of CS Condrosulf (IBSA, Lugano, Switzerland) was performed using 25mg of CS and 20–40MBq/kg body weight of 99mTc by means of the tin method. In-vivo uptake of 99mTcCS was evaluated in dogs (n=12, castrated males, 4–9years, with 15–51kg body weight). 6 healthy dogs served as controls and 6 with clinical and radiological signs of osteoarthritis in the carpal, elbow, and tarsal joint were examined. The tracer was i.v. injected into the external cephalic vein. The uptake was monitored after 2, 4, 6 and 24h in healthy and osteoarthritic dogs using a planar gamma camera by regional planar or whole body ventral and dorsal acquisition. For whole body scintigraphy animals were under general anesthesia, for planar under sedation only. ResultsIn healthy control dogs we did not detect any specific uptake of 99mTcCS in the cartilage. In contrast, in the diseased dogs suffering from osteoarthritis a significant, specific, persistent uptake between 4 and 6h in tarsal, carpal and cubital joints was documented.Median target (joint) to background (mid antebrachium) ratio (T/B) in the OA joints after 4, 6, and 24h was significantly higher than in healthy controls. Target to background ratio using soft tissue as a background (T/S) a similar significantly higher than in healthy controls.In all osteoarthritic joints we found a significant positive correlation (r=0.8, n=20) between grade of disease (I–III) and T/B. When matching radiographic (X ray) changes in osteoarthritic joints (grade II and III) we found also a maximal uptake of 99mTcCS at the specific anatomical site of highest cartilage degeneration. None of the dogs experienced any side effects. ConclusionThese results suggest that 99mTcCS might become a promising diagnostic tool for imaging osteoarthritis. More extensive and detailed examinations are required, however, before extending this methodology for application in humans.

Diagnostic features of lung metastases differentiated thyroid cancer

The aim of the study was to comparatively assess the efficacy of various diagnostic imaging modalities in detection of lung metastases of differentiated thyroid cancer. A retrospective analysis of the results of examination of 36 patients was carried out. Positron emission tomography/computed tomography (PET/ CT) with [F-18] fluorodeoxyglucose (FDG) was found to have the highest sensitivity for detection of lung metastases of differentiated thyroid cancer (100 %) followed by CT of the chest (95.5 %) and whole body scintigraphy (WBS) with 131I (66.7 %).

Physiologically Based Pharmacokinetic (PBPK) Model for Biodistribution of Radiolabeled Peptides in Patients with Neuroendocrine Tumours.

Objective(s):The objectives of this work was to assess the benefits of the application of Physiologically Based Pharmacokinetic (PBPK) models in patients with different neuroendocrine tumours (NET) who were treated with Lu-177 DOTATATE. The model utilises clinical data on biodistribution of radiolabeled peptides (RLPs) obtained by whole body scintigraphy (WBS) of the patients.Methods:The blood flow restricted (perfusion rate limited) type of the PBPK model for biodistribution of radiolabeled peptides (RLPs) in individual human organs is based on the multi-compartment approach, which takes into account the main physiological processes in the organism: absorption, distribution, metabolism and excretion (ADME). The approach calibrates the PBPK model for each patient in order to increase the accuracy of the dose estimation. Datasets obtained using WBS in four patients have been used to obtain the unknown model parameters. The scintigraphic data were acquired using a double head gamma camera in patients with different neuroendocrine tumours who were treated with Lu-177 DOTATATE. The activity administered to each patient was 7400 MBq.Results:Satisfactory agreement of the model predictions with the data obtained from the WBS for each patient has been achieved.Conclusion:The study indicates that the PBPK model can be used for more accurate calculation of biodistribution and absorbed doses in patients. This approach is the first attempt of utilizing scintigraphic data in PBPK models, which was obtained during Lu-177 peptide therapy of patients with NET.

Management of the Patient with Aggressive and Resistant Papillary Thyroid Carcinoma

Purpose:Papillary carcinoma is the most frequent type of thyroid cancer and was considered the most benign of all thyroid carcinomas, with a low risk of distant metastases. However, there are some variants of papillary thyroid carcinoma that have affinity to spread in many organs, such as: lymph nodes, lungs and bones.Aim:The aim of this study was presentation of a case with papillary carcinoma of the thyroid gland, very persistent and resistant in treatment with I 131.Material and results:A man 56 years old were diagnosed with papillary carcinoma of thyroid gland. He underwent a surgical removal of the tumor and right lobe of thyroid gland. With histopathology examination, were confirmed follicular variant of papillary carcinoma pT4. Two weeks later he underwent total thyroidectomy and was treated with 100 mCi of J 131. Six months later, the value of thyroglobulin was found elevated above upper measured limits (more than 500 ng/ml). Patient underwent surgical removal of 10 metastatic lymph nodes in the left side of the neck and has been treated with 145 mCi of radioiodine I 131. The examination after 5 months shows elevation of thyroglobulin, more than 20000 ng/ml and focally uptake of J 131 in the left lung. Patient was treated once again with 150 mCi radioiodine J 131. Whole body scintigraphy was registered focal uptake of radioiodine in the middle of the left collarbone. After a month, patient refers the enlargement of the lymph node in the right side of the neck. Currently patient is being treated with kinase inhibitor drug sorafenib and ibandronate. We have identified first positive response in treatment. Enlarged lymph node in the neck was reduced and the patient began feeling better.Conclusion:This study suggests that some subtypes of papillary thyroid carcinoma appear to have more aggressive biological course. Subtypes of papillary thyroid carcinoma such as diffuse sclerosing carcinoma, tall cell or columnar cell and insular variants, appears to have more aggressive biological course and need early detection and other kind of treatment.

Tumour-induced osteomalacia: a literature review and a case report

Tumour-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterised by severe hypophosphataemia and osteomalacia, with renal phosphate wasting that occurs in association with tumour. The epidemiology likewise aetiology is not known. The clinical presentation of TIO includes bone fractures, bone and muscular pains, and sometimes height and weight loss. TIO may be associated with mesenchymal tumours which may be benign or malignant in rare cases. Mesenchymal tumour itself may be related to fibroblast growth factor 23 (FGF23), which is responsible for hypophosphataemia and phosphaturia occurring in this paraneoplastic syndrome. Hypophosphataemia, phosphaturia and elevated alkaline phosphatase are the main laboratory readings that may lead to more precise investigations and better diagnosis. Finding the tumour can be a major diagnostic challenge and may involve total body magnetic resonance imaging, computed tomography and scintigraphy using radiolabelled somatostatin analogue. The treatment of choice for TIO is resection of a tumour with a wide margin to insure complete tumour removal, as recurrences of these tumours have been reported. We provide here an overview on the current available TIO case reports and review the best practices that may lead to earlier recognition of TIO and the subsequent treatment thereof, even though biochemical background and the long-term prognosis of the disease are not well understood. This review also includes a 4-year-long history of a patient that featured muscular pains, weakness and multiple stress fractures localised in the hips and vertebra with subsequent recovery after tumour resection. Because the occurrence of such a condition is rare, it may take years to correctly diagnose the disease, as is reported in this case report.

Évaluation d’un protocole d’acquisition de la scintigraphie osseuse en mode TEMP/TDM 3 champs de vue dans un contexte oncologique et rhumatologique

The objective of this study is to assess the potential gain of specificity and sensitivity brought by 3 field-of-view (3-FOV) SPECT-CT modality covering axial skeleton over whole body scintigraphy (WBS) and SPECT-CT in an oncologic setting and/or in the work-up of low back pain of obscure origin. Patients and methodsRetrospective study comparing the WBS and 3-FOV SPECT-CT images in 39 patients (27 males, 12 females, age: 65 ± 14 years [mean±standard deviation]). The criterion standard is composite and comprehends bone biopsy and/or metabolic imaging (pentetreotide SPECT-CT, FDG and/or NaF PET-CT, new bone scintigraphy) and morphologic imaging (MDCT, MRI) modalities. The results are analysed statistically by 95% confidence interval (95% CI). ResultsThe whole body scintigraphy (WBS) detected 409 lesions, including 252 malignant, 31 benign, and 126 indeterminate ones. On the other hand, 438 lesions were detected by the 3-FOV SPECT-CT, including 391 malignant, 31 benign, and 16 indeterminate ones. Lesionwise Se of WBS and SPECT-CT was 91% and 100% respectively. Sp was 58% and 87% respectively. The PPV was 94% and 98% respectively. NVP was 48% and 100% respectively (differences all significant). We compared lesionwise Se and Sp of 3-FOV SPECT-CT, pelvic and spinal MRI, chest-abdomen-pelvis CT of the vertebral lesions in 24 patients. Se and Sp were 98%, 100% and 100% respectively and 81%, 69% and 57% respectively (differences not significant). ConclusionThe constellation of pathophysiological, epidemiological, clinical and technical arguments contributes to consider the 3-FOV SPECT-CT unassociated to whole body scintigraphy, in clinical oncologic routine, at the cost of an exceptional theoretical risk of false negative.

A Unique Case of Intranasal Metastasis from Occult Poorly Differentiated Thyroid Carcinoma.

Poorly differentiated thyroid carcinomas (PDTCs) lie, both morphologically and behaviorally, between well-differentiated and undifferentiated carcinomas. Metastasis of poorly differentiated thyroid carcinoma to the intranasal cavity has not been reported previously in the literature. A 48-year-old male patient presented with massive epistaxis and nasal obstruction. On nasal examination, a bleeding, vascular mass was seen filling the left nasal cavity. The histopathological report of the nasal mass was well-differentiated thyroid carcinoma metastasis. Whole body scintigraphy, ultrasonography and positron emission tomography were done to rule out other possible metastases in the body and determine the origin of the tumor, which was identified as the left lobe of the thyroid gland, and there were multiple metastases involving the lung, sacroiliac area, and left humerus. Histopathological examination of a thyroidectomy specimen revealed PDTC consisting of insular, follicular, and papillary components. Postoperatively, the patient received radioactive iodine ablation therapy (iodine-131) and a course of external beam radiation therapy to the sacroiliac area and other metastatic regions. No recurrences were observed in a follow-up period of 5 years after surgery. The metastasis of differentiated thyroid carcinoma as a component of PDTC to the intranasal cavity has not been reported before. It is interesting that the well-differentiated component of the tumor was metastasized in our patient. Due to the aggressiveness of PDTC and the poor survival rates in patients who undergo surgery alone, a multidisciplinary treatment approach is required.

Transient early increase in thyroglobulin levels post-radioiodine ablation in patients with differentiated thyroid cancer

ObjectivesTreatment of differentiated thyroid cancer (DTC) includes surgical thyroidectomy and, in most cases, radioactive iodine (RAI) ablation. Measurement of serum thyroglobulin (Tg) levels is used for assessing disease burden and identifying persistent–recurrent DTC. This prospective study determined the Tg profile before and after RAI-ablation in patients with DTC. Design and methodsFifty-five DTC patients with complete resection received RAI-ablation and were assessed for Tg at baseline (non-stimulated), pre-ablation (stimulated), 7days post-ablation (stimulated) and at 6months (stimulated). Stimulation of Tg was achieved by thyroid hormone withdrawal to achieve serum thyroid stimulating hormone (TSH) ≥30mU/L. Thyroid remnant size was estimated from whole body scintigraphy. Similar protocols were implemented for nine patients with incomplete resection/metastatic disease for comparison. ResultsMean stimulated Tg levels for DTC patients with complete resection at 7days post-RAI increased 13-fold from 13.7 to 175.5μg/L (p<0.0001), and the Tg levels reduced to 2.3μg/L (p<0.0001 versus post-RAI) by follow-up. None of the patients had recurrence of disease. For the nine patients with incomplete resection/metastases, Tg levels were higher throughout compared to the patients with complete resection. There was no increase in Tg between pre- and post-RAI. We did not observe a significant correlation between the remnant size and Tg increase. ConclusionsThis study confirms a prominent transient early increase in Tg post-RAI ablation in DTC patients with complete resection, with the Tg levels falling below baseline by 6months. This is presumed to reflect RAI-induced thyroid tissue destruction/inflammation with subsequent release of Tg from the thyroid remnant. Recognizing this transient phenomenon is important for post-ablation Tg interpretation and patient management.

Post-PET ultrasound improves specificity of 18F-FDG-PET for recurrent differentiated thyroid cancer while maintaining sensitivity.

BackgroundPositron emission tomography (PET) using fluor-18-deoxyglucose (18F-FDG) with or without computed tomography (CT) is generally accepted as the most sensitive imaging modality for diagnosing recurrent differentiated thyroid cancer (DTC) in patients with negative whole body scintigraphy with iodine-131 (I-131).PurposeTo assess the potential incremental value of ultrasound (US) over 18F-FDG-PET-CT.Material and MethodsFifty-one consecutive patients with suspected recurrent DTC were prospectively evaluated using the following multimodal imaging protocol: (i) US before PET (pre-US) with or without fine needle biopsy (FNB) of suspicious lesions; (ii) single photon emission computed tomography (≥3 GBq I-131) with co-registered CT (SPECT-CT); (iii) 18F-FDG-PET with co-registered contrast-enhanced CT of the neck; (iv) US in correlation with the other imaging modalities (post-US). Postoperative histology, FNB, and long-term follow-up (median, 2.8 years) were taken as composite gold standard.ResultsFifty-eight malignant lesions were identified in 34 patients. Forty lesions were located in the neck or upper mediastinum. On receiver operating characteristics (ROC) analysis, 18F-FDG-PET had a limited lesion-based specificity of 59% at a set sensitivity of 90%. Pre-US had poor sensitivity and specificity of 52% and 53%, respectively, increasing to 85% and 94% on post-US, with knowledge of the PET/CT findings (P < 0.05 vs. PET and pre-US). Multimodal imaging changed therapy in 15 out of 51 patients (30%).ConclusionIn patients with suspected recurrent DTC, supplemental targeted US in addition to 18F-FDG-PET-CT increases specificity while maintainin sensitivity, as non-malignant FDG uptake in cervical lesions can be confirmed.

Accuracy of Radioactively Labeled Autologous Leukocytes in Patients with Infected Prosthetic Joints

Objective: A serious complication of joint replacement surgery is infection, which results in prolonged invalidity due to decrease in joint function and hospitalization, often resulting in removal and subsequent re-implantation after lengthy antibiotic therapy. Labeled leukocyte scintigraphy (LS) is considered a valuable tool in preoperative diagnosis of prosthetic joint infections. The aim of this study was to examine imaging of in vitro radioactively labeled autologous leukocytes and bone marrow scans in their accuracy and reliability in detecting infection in patients with prosthetic joints. Furthermore, inflammation markers CRP and WBC count were analyzed for their accuracy in detecting prosthetic joint infection. Methods: This single center study included all patients suspected of having prosthetic joint infections between January and September 2013 at the Vienna General Hospital. A total of 45 mL blood was drawn from a peripheral vein and leukocytes were radioactively labeled with Tc-99m-HMPAO according to protocol. The labeled leukocytes were then re-injected into a peripheral vein. A whole body scintigraphy and local images were recorded with a double-headed gamma camera four hours after re-injection. Additional local images were taken taken approximately 24 hours following re-injection. In the case of positive LS, bone marrow scintigraphy was conducted 48 hours after re-injection. Local images were recorded 30 minutes after injection of 370 MBq Tc-99m-nanocolloid. Results: This study included a total of 50 patients. All the patients underwent subsequent bacterial and histological testing via joint aspiration or operation of the joint. The most common joint investigated was knee (27), followed by hip (9), shoulder (2), and elbow (1). Other cases involved the complete femur (6), tibia (2), leg (2), and foot (1). Pathogens isolated from the joints included Staphylococcus epidermidis and Candida albicans. The sensitivity of LS was 63%, specificity 90%, PPV 56% and NPV 93%. Overall accuracy was calculated to be 86%. Pre-diagnostic testing with CRP and WBC was conducted in 43 patients. Mean CRP was 3,9 mg/dl. Thirty-one patients had a CRP-level higher and 12 patients lower than the cut-off. The sensitivity was 57%, specificity 28%, PPV 13%, NPV 77% and accuracy 33%. Lastly, only 3 patients had WBC counts higher than the cut-off. WBC count had a sensitivity of 0%, specificity 92%, PPV 0%, NPV 88% and overall accuracy 82%. Conclusion: While this study showed that CRP and WBC are not accurate pre-diagnostic markers for prosthetic joint infection, it was able to demonstrate that Tc-99m-HMPAO labeled autologous leukocytes in patients presenting with symptoms of prosthetic joint infection is accurate. LS is a feasible imaging method in patients with infection of prosthetic joints and may