Performance of [68Ga]Ga-PSMA-11 PET/CT in patients with recurrent prostate cancer after prostatectomy-a multi-centre evaluation of 2533 patients.

PURPOSE: To evaluate the performance of [68Ga]Ga-PSMA-11 PET/CT in the diagnosis of recurrent prostate cancer (PC) after prostatectomy in a large multicentre cohort. METHODS: The centres, which contributed to this study, were the departments of nuclear medicine of Heidelberg (Germany), Technical University of Munich (Germany) and Albert Einstein Hospital of São Paulo (Brazil). A total of 2533 patients who were scanned with [68Ga]Ga-PSMA-11 PET/CT at 1 h p.i. due to recurrent PC after prostatectomy were included in this retrospective analysis. Exclusion criteria were as follows: patients with untreated primary tumour, previous chemotherapy or Xofigo®; those previously treated with exclusively external beam radiation therapy or HIFU; those referred for PSMA-therapy; and those treated with ADT (including first- and second-generation ADT) within the last 6 months. Potential influences of different factors such as PSA level, PSA doubling-time (PSADT), PSA velocity (PSAVel), Gleason Score (GSC, including the separate analysis of 7a and 7b), age and amount of injected tracer were evaluated in a multivariable analysis. RESULTS: The rate of pathologic PET/CT-scans was 43% for PSA ≤ 0.2 ng/ml, 58% for PSA > 0.2 to ≤ 0.5, 72% for PSA > 0.5 to ≤ 1.0 and increased to a maximum of 93% for PSA > 10 ng/ml. A pathological PET/CT was significantly (p = 0.001) associated with PSA level and higher GSC. Amount of injected tracer, age, PSADT and PSAVel were not associated with a higher probability of a pathological scan. CONCLUSION: [68Ga]Ga-PSMA-11 PET/CT at 1 h p.i. confirmed its high performance in the largest patient cohort yet analysed. Tumour detection showed a clear association with higher PSA and higher GSC. No association was found between a pathological [68Ga]Ga-PSMA-11 PET/CT and age, amount of injected tracer, PSADT or PSAVel.

68Ga-DOTATATE PET/CT in recurrent medullary thyroid carcinoma: a lesion-by-lesion comparison with 111In-octreotide SPECT/CT and conventional imaging.

PURPOSE: The aim of this study was to prospectively compare the detection rate of 68Ga-DOTATATE PET-CT with 111In-octreotide SPECT-CT and conventional imaging (CI) in medullary thyroid carcinoma (MTC) patients with increased calcitonin (Ctn) levels but negative CI after thyroidectomy. METHODS: Fifteen patients with raised Ctn levels and/or CI evidence of recurrence underwent 68Ga-DOTATATE PET-CT, 111In-octreotide SPECT-CT and CI. Histopathology, CI and biochemical/clinical/imaging follow-up were used as the reference standard. PET/CT, SPECT/CT and CI were compared in a lesion-based and organ-based analysis. RESULTS: PET/CT evidenced recurrence in 14 of 15 patients. There were 13 true positive (TP), 1 true negative (TN), 1 false positive (FP) and no false negative (FN) cases, resulting in a sensitivity and accuracy of 100% and 93%. SPECT/CT was positive in 6 of 15 cases. There were 6 TP, 2 TN, 7 FN and no FP cases, resulting in a sensitivity of 46% and accuracy of 53%. CI procedures detected tumor lesions in 14 of 15 patients. There were 13 TP, 1TN, 1 FP and no FN cases with a sensitivity of 100% and accuracy of 93%. A significantly higher number of lesions was detected by PET/CT (112 lesions, p = 0.005) and CI (109 lesions, p = 0.005) in comparison to SPECT/CT (16 lesions). There was no significant difference between PET/CT and CI for the total number of detected lesions (p = 0.734). PET/CT detected more lesions than SPECT/CT regardless of the organ. PET/CT detected more bone lesions but missed some neck nodal metastases evidenced by CI. The number of lesions per region demonstrated by PET/CT and CI were similar in the other sites. CONCLUSION: 68Ga-DOTATATE PET/CT is superior to 111In-octreotide SPECT/CT for the detection of recurrent MTC demonstrating a significantly higher number of lesions. 68Ga-DOTATATE PET/CT showed a superior detection rate compared to CI in demonstrating bone metastases.

THE COMBINED USE OF CALCITONIN DOUBLING TIME AND 18F-FDG PET/CT IMPROVES PROGNOSTIC VALUES IN MEDULLARY THYROID CARCINOMA: THE CLINICAL UTILITY OF 18F-FDG PET/CT.

OBJECTIVE: Calcitonin and carcinoembryonic antigen (CEA) doubling times are established prognostic markers in medullary thyroid cancer (MTC). On the other hand, 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) shows an increased rate of detection with high blood tumor marker levels in several cancers. This study aimed to analyze the ability of 18F-FDG PET/CT to determine prognosis in the follow-up of patients with MTC. METHODS: Medical records of 17 patients with MTC who underwent 18F-FDG PET/CT were analyzed retrospectively. All patients were classified into two groups: stable disease or progressive disease. RESULTS: Eight patients presented with progressive disease, and all of them showed 18F-FDG uptake (100%), compared to only 3 of 9 patients who presented in stable condition (33%). 18F-FDG PET/CT results were able to distinguish progressive from stable disease (P = .009). Calcitonin levels >4,020 pg/mL (P = .0004), CEA levels >26.8 ng/mL (P = .04), and a calcitonin doubling time <24.1 months (P = .015) were associated with progressive disease in our cohort. The proportion of variance explained that predicted progressive disease was 32% for 18F-FDG uptake, 27.1% for a calcitonin doubling time of 24.1 months, and 41.2% for doubling time plus 18F-FDG PET/CT. CONCLUSION: 18F-FDG uptake was able to distinguish progressive from stable disease. However, this tool should not replace the validated calcitonin doubling time, but rather the combination of information could improve the clinical re-assessment and better identify high-risk patients who require more careful surveillance. ABBREVIATIONS: CEA = carcinoembryonic antigen CT = computed tomography 18F-FDG = 18F-fluorodeoxyglucose MTC = medullary thyroid cancer PET = positron emission tomography PVE = proportion of variance explained sCT = serum calcitonin SUV = standard uptake value US = ultrasound.

99mTc-HYNIC-TOC increased uptake can mimic malignancy in the pancreas uncinate process at somatostatin receptor SPECT/CT.

OBJECTIVE: The aim of this study was to assess the occurrence and frequency of increased physiologic uptake of 99mTc-HYNIC-TOC by the uncinate process of the pancreas in SPECT/CT images. METHODS: Forty-six scans of 41 patients were evaluated retrospectively. The uptake of 99mTc-HYNIC-TOC was considered to be physiologic in patients with normal findings at dedicated abdominal CT or MR and lack of neoplastic lesions in clinical follow-ups. The intensity of uncinate process uptake was compared to the uptake of the normal liver. RESULTS: Focal uptake was attributed to the presence of pancreatic NET in 5 patients. Among the 36 patients without any evidence of malignancy in CT, MR and follow-up, 7 (19.4 %) showed increased uptake in the uncinate process. The intensity of uptake was lesser in 3 (8.3 %), similar in 3 and greater than the normal liver in 1 (2.8 %) case. CONCLUSION: Increased 99mTc-HYNIC-TOC uptake occurred in 19.4 % of those subjects without any evidence of neuroendocrine tumor in the uncinate process.

Low-dose radiation protocol using 3D mode in a BGO PET/CT.

BACKGROUND: The use of positron emission tomography combined with computed tomography (PET/CT) has brought about significant technological advancement in diagnostic imaging, and a number of PET/CT scanners with bismuth germanate detectors can perform imaging in both 2D and 3D acquisition modes. Nevertheless, certain image acquisition parameters and physical features of patients have to be considered when designing low-dose protocols in the 3D mode. PURPOSE: The aim of this study was to compare images acquired in 2D and 3D modes and establish a low-dose protocol for use in PET/CT imaging, decreasing patient exposure to radiation without compromising results. METHODS: A total of 30 patients, aged 4-72 years, participated in this prospective study, which was conducted at Albert Einstein Hospital, São Paulo, Brazil. Images were evaluated for picture quality, presence/absence of lesions and the number of lesions that were detectable in both acquisition modes. RESULTS: The results consistently showed that the loss in image quality in the 3D mode did not affect exam interpretation and lesion detection when compared with 2D at higher dose and for a longer time. CONCLUSIONS: We therefore conclude that administration of 3.7 MBq [(18)F]-fluorodeoxyglucose (FDG)/kg for an acquisition time of 3 min per FOV (field of view) is optimal for image acquisition in the 3D mode. This protocol, which reduces the acquisition time and radiation dose, is quite beneficial, especially for children.

Comparative analysis of somatostatin analog uptake between successfully irradiated and non-irradiated meningiomas.

OBJECTIVE: To evaluate whether there is a significant difference in somatostatin analog uptake in meningiomas treated or not with radiation therapy. METHODS: A cross-sectional study was performed comparing measurements of somatostatin analog (68Ga-DOTATATE) uptake in two independent groups of ten patients each - one consisting of patients with meningiomas previously treated with radiation therapy and another comprising patients who had never been submitted to radiation therapy. All patients underwent PET/CT and MRI scans in an interval shorter than 24 hours between exams. RESULTS: A total of 32 meningiomas from 20 patients were analyzed, all presenting significant somatostatin analog uptake in different degrees. The uptake levels of somatostatin analog were similar between the lesions treated or not with radiation therapy, and the mean values of SUVmax were 27.62 and 24.82, respectively (p=0.722). For SUVmean, the values were 16.20 and 14.82, respectively (p=0.822). CONCLUSION: Comparative analysis between the groups showed no significant differences in degree of somatostatin analog uptake in successfully irradiated and non-irradiated meningiomas.

Evaluation of dopamine transporter density in healthy Brazilians using Tc-99m TRODAT-1 SPECT.

ABSTRACT: The presynaptic dopamine transporter (DAT) modulates the uptake of dopamine by regulating its concentration in the central nervous system. We aimed to evaluate the DAT binding potential (DAT-BP) in a sample of healthy Brazilians through technetium-99 metastable TRODAT-1 single-photon emission computed tomography imaging.We selected 126 healthy individuals comprising 72 men and 54 women, aged 18 to 80 years. We conducted semi-quantitative evaluation in transaxial slices, following which we identified the regions of interest in the striatal region using the occipital lobe as a region of non-specific DAT-BP.We found a decrease in DAT-BP in healthy individuals aged over 30 years, culminating in a 42% mean reduction after 80 years. There was no difference in the decrease by age group between the right (linear regression test [R2] linear = 0.466) and left striatum (R2 linear = 0.510). Women presented a higher DAT-BP than men (women: R2 linear = 0.431; men: R2 linear = 0.457); nonetheless, their decrease by age group was equal to that in men.Our study sheds light on important DAT-BP findings in healthy Brazilian subjects. Our results will facilitate understanding of brain illnesses that involve the dopamine system, such as neuropsychiatric disorders.

Metastatic carcinoma of unknown primary with complete metabolic response following sorafenib-based chemotherapy.

BACKGROUND: The treatment of carcinoma of unknown primary based on histopathology and immunohistochemistry is generally chemotherapy. The use of molecular markers, genetic profiling platforms, and personalized medicine is under active investigation. CASE REPORT: We report the case of a 56-year-old patient who presented to medical attention with palpable axillary adenopathy. Biopsy confirmed poorly differentiated adenocarcinoma. Formal staging revealed extensive metastatic disease to bone and liver. Initial chemotherapy proved ineffective. We describe the diagnostic evaluation, treatment, and achievement of durable remission using a novel sorafenib-based drug combination that was chosen through the application of a functional analytic laboratory platform. CONCLUSION: The clinical management of patients with carcinoma of unknown primary continues to present a considerable challenge for practicing oncologists. Laboratory platforms capable of examining cellular response to injury, growth factor withdrawal, and cytotoxic insult at the level of cellular function may provide insights for drug selection in this patient population.

[Diagnostic value of positron emission tomography/computed tomography with fluorine-18 fluordeoxyglucose in patients with differentiated thyroid gland carcinoma, high thyroglobulin serum levels and negative iodine whole body scan]. / Valor diagnóstico da tomografia por emissão de pósitrons/tomografia computadorizada (PET-CT) com flúor-18 fluordeoxiglicose (FDG-18F) em pacientes com carcinoma diferenciado da tireóide, níveis séricos de tireoglobulina elevados e pesquisa de corpo inteiro com iodo negativa.

PURPOSE: To evaluate the role of PET-CT with FDG-18F in the detection of recurrence and/or metastasis of differentiated thyroid carcinoma (DTC) in patients with elevated levels of thyroglobulin (TG) and negative whole body scan (WBS). PATIENTS AND METHOD: PET-CT findings of 25 patients were compared to histopathology evaluation and conventional imaging (CI). RESULTS: PET-CT scan was positive in 16 patients finding 14 true-positive and 2 false-positive cases (positive predictive value 87.5%). Nine patients had negative PET-CT; two had decrease of TG to undetectable levels. One patient had residual disease detected by post-therapeutic WBS. Six patients had no evidence of tumor during follow-up (mean time 16 months). PET-CT was concordant with CI in 52%, partially concordant in 12% and discordant in 36% (6 false-negatives and 3 false-positive of CI). We observed a tendency of increasing proportion of positive PET-CT with increasing TG. CONCLUSION: PET-CT scan with FDG-18F is useful in the detection of recurrence and/or metastases of DTC with high TG levels but negative WBS. It presents elevated positive predictive value and is superior to CI being more effective as higher the serum TG levels.

68Ga-DOTATATE PET/CT in Nonneuroendocrine Tumors: A Pictorial Essay.

PET-CT with somatostatin analogs labeled with Ga is increasingly recognized as the best imaging modality for the evaluation of well-differentiated neuroendocrine tumors (NETs). However, somatostatin receptor (SSR) is not an exclusive marker for NET. A variety of tumors other than NETs express SSR, leading to a significant risk of false-positive PET/CT results. We illustrate false-positive Ga-DOTATATE PET/CT findings due to high uptake by non-Hodgkin lymphoma, metastatic meningioma, breast cancer, thyroid adenoma, and papillary carcinoma. Although Ga-DOTATATE is a noteworthy tracer for oncological application, pathological conditions with overexpression of SSR should be recognized to prevent misinterpretation of PET/CT images.

PET/MRI: a novel hybrid imaging technique. Major clinical indications and preliminary experience in Brazil.

In recent years, medical imaging with hybrid techniques has widely accepted and employed in clinical routine. PET/MRI offers significant advantages, including excellent contrast and resolution and reduced ionizing radiation, as compared to well-established PET/CT. Therefore, PET/MRI is a promising modality for oncologic imaging of some regions, such as brain, head and neck, liver and pelvis. This article set out to analyze clinical conditions that could benefit from PET/MRI imaging based on our caseload. The potential of PET/MRI to become the imaging modality of choice for assessment of neurologic and oncologic conditions associated with soft tissues is highlighted. Clinical aspects of PET/MRI and its application to clinical cases are illustrated with examples extracted from the authors' preliminary experience. RESUMO Nos últimos anos, imagens médicas com tecnologias híbridas tornaram-se amplamente aceitas e utilizadas na prática clínica. O PET/RM possui vantagens importantes, incluindo excelentes contrastes e resolução, e menor radiação ionizante, em comparação ao PET/TC. Por isto, é uma modalidade promissora para exames de imagem de pacientes oncológicos, para avaliar o cérebro, cabeça e pescoço, o fígado e a pelve. O objetivo deste artigo foi analisar as situações clínicas que se beneficiariam de exames de PET/RM a partir de uma casuística. Destacamos o potencial desta técnica se tornar o método de imagem de escolha para doenças neurológicas e oncológicas que envolvam partes moles. Os aspectos clínicos de PET/RM e sua aplicação aos casos clínicos são ilustrados com exemplos da experiência inicial dos autores.

Clinical utility of 18F-FDG PET/CT in the follow-up of a large cohort of patients with high-risk differentiated thyroid carcinoma.

OBJECTIVE: To evaluate the clinical utility of 18F-FDG PET/CT in patients with high-risk DTC. SUBJECTS AND METHODS: Single-center retrospective study with 74 patients with high-risk differentiated thyroid cancer (DTC), classified in 4 groups. Group 1: patients with positive sTg or TgAb, subdivided in Group 1A: negative RxWBS and no foci of metastases identified at conventional image (n = 9); Group 1B: RxWBS not compatible with suspicious foci at conventional image or not proportional to sTg level (n = 13); Group 2: patients with histological findings of aggressive DTC variants (n = 21) and Group 3: patients with positive RxWBS (n = 31). RESULTS: 18F-FDG PET/CT identified undifferentiated lesions and helped restage the disease in groups 1B and 2. The scan helped guide clinical judgment in 9/13 (69%) patients of group 1B, 10/21 (48%) patients of group 2 and 2/31 (6%) patients of group 3. There was no clinical benefit associated with group 1A. 18F-FDG PET/CT was associated with progressive disease. CONCLUSION: 18F-FDG PET/CT is a useful tool in the follow-up of patients with high-risk DTC, mainly in the group of RxWBS not compatible with suspicious foci at conventional image or not proportional to sTg level and in those with aggressive DTC variants. Additionally, this study showed that 18F-FDG PET/CT was associated with progression and helped display undifferentiated lesions guiding clinical assessments regarding surgeries or expectant treatments.

Comparative analysis of somatostatin analog uptake between successfully irradiated and non-irradiated meningiomas

Abstract Objective To evaluate whether there is a significant difference in somatostatin analog uptake in meningiomas treated or not with radiation therapy. Methods A cross-sectional study was performed comparing measurements of somatostatin analog (68Ga-DOTATATE) uptake in two independent groups of ten patients each - one consisting of patients with meningiomas previously treated with radiation therapy and another comprising patients who had never been submitted to radiation therapy. All patients underwent PET/CT and MRI scans in an interval shorter than 24 hours between exams. Results A total of 32 meningiomas from 20 patients were analyzed, all presenting significant somatostatin analog uptake in different degrees. The uptake levels of somatostatin analog were similar between the lesions treated or not with radiation therapy, and the mean values of SUVmax were 27.62 and 24.82, respectively (p=0.722). For SUVmean, the values were 16.20 and 14.82, respectively (p=0.822). Conclusion Comparative analysis between the groups showed no significant differences in degree of somatostatin analog uptake in successfully irradiated and non-irradiated meningiomas.

[Neuroimaging of the dopamine transporter in Parkinsons disease: first study using [99mTc]-TRODAT-1 and SPECT in Brazil]. / Neuroimagem do transportador de dopamina na doença de Parkinson: primeiro estudo com [99mTc]-TRODAT-1 e SPECT no Brasil.

BACKGROUND: Dopamine transporter (DAT) neuroimaging radiotracers were developed to estimate dopamine neuronal loss in vivo in Parkinsons disease (PD). OBJECTIVE: To evaluate DAT density in vivo using [99mTc]-TRODAT-1 and single photon computerized tomography (SPECT) in a population of Brazilian PD. METHOD: Fifteen PD patients and 15 matched healthy controls scanned with [99mTc]-TRODAT-1 (INER-Taiwan) and SPECT. Estimates of striatum DAT density were calculated using binding potential (BP). Patients were assessed with PD scales. RESULTS: PD patients had significantly lower striatal DAT-BP (mean+/-SD) (0.38+/-0.12) compared to controls (BP=0.84+/-0.16; p<0.01). A 100% sensitivity and 100% specificity was obtained to discriminate PD cases from controls. Negative correlations between striatal DAT-BP and PD severity (rho=-0.7, p<0.001) and motor scales (rho=-0.80, p<0.001) were found. CONCLUSION: [99mTc]TRODAT-1 SPECTs scanning was able to discriminate PD patients from controls. The technique is a powerful instrument to measure DAT density that can be used in clinical and research settings in Brazil.

Vital dye is enough for inguinal sentinel lymph node biopsy in melanoma patients.

PURPOSE: The importance of gamma probe detection (GPD) combined with vital dye for sentinel node (SN) biopsy is well accepted. We evaluated the efficacy of patent blue dye (PBD) in identifying inguinal SN. METHODS: Ninety-four cutaneous melanoma patients with inferior extremity lesions were submitted to SNB according to a established protocol. Patients were randomized in two groups: Blue group, where SN was identified by PPD and Probe group, where SN was identified by GPD. The median age was 44.2 years and median Breslow thickness was 2.1 mm. Preoperative lymphoscintigraphy, lymphatic mapping with PBD and intra-operative GPD was performed on all patients. Histological examination of SN consisted of hematoxylin-eosin and immunohistochemical staining. If micrometastases were present complete lymphadenectomy was performed. The SN was considered as identified by PBD if it was blue and identified by GPD if it demonstrated at least ten times greater radioactivity than background. RESULTS: It was explored 94 inguinal lymphatic basins, 145 SN were excised (70 guided primarily by blue dye and 75 guided primarily by probe). All SN identified by preoperative lymphoscintigraphy were excised. In the Blue group PPD identified all SN and all of them were hot. In the Probe group all SN were identified by probe and were blue. The coincidence of PPD and GPD was 100%. CONCLUSION: Patent blue dye is enough to identify superficial inguinal SN in cutaneous melanoma.

Is PET-CT an accurate method for the differential diagnosis between chondroma and chondrosarcoma?

The differential diagnosis between chondroma and intraosseous chondrosarcoma is based on imaging and clinical exams, but only a biopsy can confirm diagnosis. The aim of this study was to evaluate the value of PET-CT in differentially diagnosing chondroma and chondrosarcoma. From October 2009 to May 2015, 36 patients with cartilaginous bone lesions in the extremities, 12 (33.3 %) men and 24 (66.6 %) women, were prospectively included in the study. Patients ranged in age from 21 to 68 years, with a mean age of 44 years. Lesions were located in the long bones: in the proximal humerus in 26 (72.2 %) patients, in the femoral shaft in 1 (2.7 %), in the distal femur in 7 (19.4 %), and in the proximal tibia in 2 (5.5 %). The SUVmax value of 2.0 was used to separate between patients submitted to surgery and patients submitted to observation. Among the 36 patients studied, 17 (47.2 %) had SUVmax ≤ 2.0, and they were diagnosed as chondroma and they were treated conservatively. Follow-up ranged from 14 to 76 months, averaging 38 months. Nineteen (52.7 %) patients with SUVmax >2.0 were diagnosed as chondrosarcoma and underwent surgery. The area of the curve, calculated considering the SUV variable as numeric, is estimated in 0.966, with a 95 % confidence interval from 0.906 to 1.000. To evaluate the sensitivity, specificity and positive/negative predictive values, it was built a 2 × 2 table. Significance was set at p < 0.05. According the criteria of maximum sensitivity and specificity, the cut point suggested to SUVmax was 2.2. If we consider this point, it is possible to identify 19 of 36 positive cases to chondroma (52.8 %), it means, all chondrosarcomas of the series. We concluded that PET-CT can be used as an objective and quantitative method of differentiating between chondromas and chondrosarcomas located within the long bones. It represents a complementary examination to standard imaging (X-ray, scintigraphy, CT and MRI) and pathological exams. The SUVmax between 2.0 and 2.2 would be a range area between chondroma and chondrosarcoma and this range can be of value, among others exams, in decide the best treatment for patients with cartilaginous lesions in long bones. Level of evidence Level I-diagnostic study-prospectively investigating a diagnostic test using a universally applied "gold" standard.

A Prospective Study Showing an Excellent Response of Patients with Low-Risk Differentiated Thyroid Cancer Who Did Not Undergo Radioiodine Remnant Ablation after Total Thyroidectomy.

OBJECTIVES: To prospectively evaluate the outcome of patients with low-risk papillary thyroid carcinoma treated with total thyroidectomy (TT) who did not undergo radioiodine remnant ablation (RRA). STUDY DESIGN: We prospectively followed up 57 patients; 3 months after TT, thyroglobulin (Tg) assessment and neck ultrasonography (US) were performed while patients were taking l-T4, presenting suppressed TSH. Six months after TT, patients underwent stimulated Tg testing and whole-body scan (WBS) after recombinant TSH (rhTSH). Then, 18 months after TT, the patients were evaluated by neck US and Tg under TSH between 0.5 and 2.0 mIU/ml. Two years after TT, we performed another rhTSH assessment, measuring Tg and making a WBS. The patients were then annually monitored with neck US and Tg measurement under TSH between 0.5 and 2.0 mIU/l for 36-84 months. RESULTS: Neck US of all patients, 3 months after TT, presented no evidence of abnormal residual tissues or metastatic lymph nodes (negative neck US); at this time, the mean Tg level was 0.42 ng/ml. Six months after surgery, after rhTSH, the mean thyroid bed uptake was 1.82%, and Tg levels ranged from 0.10 to 22.30 ng/ml (mean, 2.89 ng/ml). The patients were followed up without any sign of recurrence (negative neck US and stable or decreasing Tg levels). During the ongoing follow-up, the Tg trend was stable or decreasing, independently of the initial suppressed or stimulated Tg level, or WBS uptake. CONCLUSIONS: In patients with low-risk differentiated thyroid cancer, who were operated by TT and who did not undergo RRA, an excellent response to treatment may be confirmed by annual neck US and Tg trend.

Normalization of lymphocyte count after high ablative dose of I-131 in a patient with chronic lymphoid leukemia and secondary papillary carcinoma of the thyroid. Case report.

The authors report the case of a 70-year-old male patient with chronic lymphoid leukemia who presented subsequently a papillary carcinoma of the thyroid with metastases to regional lymph nodes. The patient was treated with surgical thyroidectomy with regional and cervical lymph node excision and radioiodine therapy (I-131). The protocolar control scintigraphy 4 days after the radioactive dose showed I-131 uptake in both axillae and even in the inguinal regions. PET/CT showed faint FDG-F-18 uptake in one lymph node of the left axilla. An ultrasound guided fine needle biopsy of this lymph node identified by I-131 SPECT/CT and FDG-F-18 PET/CT revealed lymphoma cells and was negative for thyroid tissue and thyroglobulin content. The sequential blood counts done routinely after radiation treatment showed a marked fall until return to normal values of leucocytes and lymphocytes (absolute and relative), which were still normal in the last control 19 months after the radioiodine administration. Chest computed tomography showed a decrease in size of axillary and para-aortic lymph nodes. By immunohistochemistry, cells of the lymphoid B lineage decreased from 52% before radioiodine therapy to 5% after the procedure. The authors speculate about a possible sodium iodide symporter expression by the cells of this lymphoma, similar to some other non-thyroid tumors, such as breast cancer cells.