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Background: The aim of this study is to clarify the critical organs that limit treatment scheme and also evaluate the validity of currently used critical organ threshold values in neuroendocrine tumor (NET) patients, receiving peptide receptor radionuclide therapy (PRRT) with Lutetium-177 (177Lu)-DOTATATE. Thirty-six NET patients (ages 16-73 years) who received 177Lu-DOTATATE treatment were evaluated retrospectively in this study. Dosimetric calculations were made using medical internal radionuclide dose method. For calculation of organ doses, Internal Dose Assessment at Organ Level/Exponential Modelling 1.1 software program was used. Follow-up data were used to determine the organ failure. Results: A total of 141 cycles and mean of 3.91 (±1.33) cycles were applied to the patients. A mean of 691 mCi (±257 mCi) 177Lu-DOTATATE infusion in total and a dose between 70 and 200 mCi per treatment was applied to patients. Seven of 36 patients reached 23 Gy renal dose limit. In these patients, although kidney doses were between 23 and 29 Gy, there was no diminution in renal functions during follow-up. Two of 36 patients reached total bone marrow dose of 2 Gy limit. Bone marrow suppression did not develop in these patients. Conclusion: The critical organs that seem to affect the treatment scheme in PRRT with 177Lu-DOTATATE are kidney and bone marrow. Although there are established threshold levels, derived from radiotherapy experience, more studies are needed to clarify these dose limits in systemic radionuclide therapies such as PRRT.

Purpose Prostate-specific membrane antigen (PSMA)-targeted therapies are among the current promising treatments. We present our preliminary results on the use of 225Ac-PSMA therapy in patients with metastatic castration-resistant prostate cancer as a single center. Methods Twelve advanced stage metastatic castration-resistant prostate cancer patients who received 225Ac-PSMA therapy were recruited in this retrospective study. Patients were treated with 225Ac-PSMA therapy every 8 weeks, and prostate-specific antigen (PSA) response was analyzed. Meanwhile, overall survival (OS) and progression-free survival (PFS) were estimated. Hematological and nonhematological adverse effects were recorded before and at 8 weeks after the last treatment cycle. Results In total, 25 cycles of 225Ac-PSMA were administered to 12 patients. The pretreatment median PSA level was 129 ng/mL. After the first cycle of therapy, any PSA response was observed in 9 of 12 patients, whereas 6 of them had biochemical response of >50%. Four of 12 patients reached the best PSA response after the first treatment cycle, whereas 3 patients after the second and 2 patients after the third cycle. The median PFS and OS were 4 and 10 months, respectively. For patients with any PSA response after the first cycle, OS was found to be higher despite without any statistical significance (10 vs 4 months; P = 0.301) when compared with the nonresponsive group. No significant difference was encountered in terms of adverse effect in the pretreatment and posttreatment era. Conclusions Our preliminary results are encouraging, especially patients who had PSA response after the first cycle of 225Ac-PSMA therapy.

This study investigates the prognostic value of 68Ga-Pentixafor PET/CT using PET-derived quantitative in multiple myeloma (MM) patients with suspected recurrence in comparison to 18F-FDG PET/CT and clinical data. Twenty-four MM patients with suspicion for relapse who underwent 68Ga-Pentixafor and 18F-FDG PET/CT were retrospectively evaluated. Total bone marrow glycolysis for 18F-FDG (TBMFDG) and total bone marrow uptake for 68Ga-Pentixafor PET/CT (TBMCXCR4) were calculated using whole-body metabolic tumor burden obtained by dedicated software (MIM 7.0.6). The patients were followed for 19–24 months, and the association of PET-derived quantitative data with overall survival (OS) was analyzed. 68Ga-Pentixafor PET/CT was positive in 17 patients, of which 13 were also positive on 18F-FDG PET/CT, whereas 7 patients were negative on both scans. The positive rate of 68Ga-Pentixafor and 18F-FDG PET/CT on a patient-based approach was 70.8% and 54.1%, respectively. 68Ga-Pentixafor positivity was significantly associated with OS (p = 0.009), and 18F-FDG positivity was at the margin of statistical significance (p = 0.056). TBMCXCR4 and TBMFDG were negatively correlated with OS (r = −0.457, p = 0.025 and r = −0.617, p = 0.001, respectively). The OS was negatively correlated with beta-2-microglobulin levels (r = −0.511, p = 0.01) and CRAB score (r = −0.592, p = 0.002) as an indicator of the end-organ disease, which confirmed these results. Serum beta-2-microglobulin levels and CRAB score were also correlated with TBMCXCR4 (r = 0.442, p = 0.039 and r = 0.573, p = 0.003, respectively) and TBMFDG (r = 0.543, p = 0.009 and r = -0.424, p = 0.003, respectively). 68Ga-Pentixafor PET/CT positivity is a negative prognostic factor in the survival outcome of MM patients. Complementary 68Ga-Pentixafor PET/CT has the potential to overcome 18F-FDG PET/CT limitations and helps a more precise risk stratification.

We aimed to evaluate the role of bone scintigraphy (BS) which has long been the imaging modality of choice in prostate cancer (PCa) and performed a head-to-head comparison between BS, BS + SPECT/CT and 68 Ga-PSMA-PET/CT, for the detection of bone metastasis of PCa. We evaluated 138 PCa patients who underwent BS and 68 Ga-PSMA PET/CT and SPECT/CT of 102 of 138 patients. Images were interpreted retrospectively and areas of abnormally increased tracer uptake related to PCa were documented as benign, metastatic or equivocal. Equivocal uptakes were finally diagnosed based on a consensus review of correlative imaging. Patient- and lesion-based analysis was performed. Patients with superscan images were excluded from lesion-based analysis. At least one metastatic or equivocal uptake in skeleton was defined in 76 of 138 (55%) BS, in 33 of 102 (32.3%) SPECT/CT, and in 49 of 138 (35.5%) 68 Ga-PSMA PET/CT. 23 (16.7%) patients had also superscan findings on BS and 68 Ga-PSMA PET/CT. For patient-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were calculated as 91.1%, 64.5%, 73.1%, 55.4% and 93.7% for BS; 95.5%, 82.7%, 86.9%, 72.8% and 96.2% for BS + SPECT/CT; 97.7%, 95.7%, 95.6%, 91.6% and 98.8% for 68 Ga-PSMA PET/CT. For lesion-based analysis, sensitivity, specificity, accuracy, PPV, and NPV were 53%, 63.9%, 60.1%, 42.8% and 71.8% for BS; 59.2%, 87.6%, 77.7%, 62.6% and 80% for BS + SPECT/CT; 96.4%, 98.1%, 97.5%, 96.4% and 98.1% for 68 Ga-PSMA PET/CT. This study has shown that 68 Ga-PSMA PET/CT overcomes the limitations of BS and proves superiority in detecting bone metastases, even in patients with SPECT/CT. Our findings present important implications that 68 Ga-PSMA PET/CT can replace BS in future practice.

We aimed to evaluate the predictive value of FDG PET-CT scan and CEA measurements in recurrent colorectal cancer (CRC) patients. The records of 211 CRC patients who had FDG PET-CT scans between April 2009 and June 2011 due to suspicion of recurrence were extracted from the data of our previous report of 235 patients after 24 patients were excluded from the study due to lack of follow-up data or death unrelated to CRC. FDG PET-CT findings, simultaneous CEA levels, and survival data were evaluated retrospectively to determine the prognostic factors that affected the overall survival (OS) of the patients. The mean age of 211 patients was 60.2 ± 12.8 years. The median follow-up time was 39 months (CI 95%: 4–123 months). The CRC-related death rate was 71.6% and the median OS time was measured 39 months (CI 95%: 27–50 months) for 211 patients. The median OS time for the patients with positive findings for recurrence in PET scans was 28 months (CI 95%: 22–33 months) which was significantly shorter (p

Objectives This study is set out to estimate the radiation-absorbed doses to normal organs and tumor tissue using low-dose 177Lu-FAPI04 dosimetry to determine the safety and theranostic potential of fibroblast activation protein-targeted radionuclide therapy. Patients and methods Four patients with metastatic advanced-stage cancer were administered low-dose 177Lu-FAPI04 for dosimetry measurements. Data acquisition for dosimetry of normal organs and tumors was performed by whole-body and 3D SPECT/CT imaging at 4, 24, 48, and 96 hours after administering 177Lu-FAPI04. Blood samples were drawn at 5, 15, 30, 60, 60, 120, and 180 minutes, and at 24, 48, and 96 hours for bone marrow dosimetry calculations. Results Mean absorbed doses per megabecquerel were 0.25 ± 0.16 mGy (range, 0.11-0.47 mGy), 0.11 ± 0.08 mGy (range, 0.06-0.22 mGy), and 0.04 ± 0.002 mGy (range, 0.04-0.046 mGy) for kidneys, liver, and bone marrow, respectively. The respective maximum estimated amount of radioactivity to reach radiation-absorbed dose limits were 120.9 ± 68.6 GBq, 47.5 ± 2.8 GBq, 397.8 ± 217.1 GBq, and 52.4 ± 15.3 GBq for kidneys, bone marrow, liver, and total body. The mean absorbed dose per megabecquerel was 0.62 ± 0.55 mGy for bone metastases, 0.38 ± 0.22 mGy for metastatic lymph nodes, 0.33 ± 0.21 mGy for liver metastases, and 0.37 ± 0.29 for metastatic soft tissue. The maximum absorbed dose in a tumor lesion was 1.67 mGy/MBq for bone, 0.6 mGy/MBq for lymph node, 0.62 mGy/MBq for liver, and 1 mGy/MBq for soft tissue. Conclusions The mean absorbed dose to organs at risk with 177Lu-FAPI04 is reasonably low, allowing for low tumor-absorbed dose rates by administering a higher dose. Further research on optimizing therapeutic efficacy and using alternative radioisotopes is necessary, along with an individualized dosimetric approach.

Herein, we present a 72-year-old woman with metastatic thymic carcinoma, referred for salvage peptide receptor radionuclide therapy with 177Lu-DOTATATE after completing all treatment options according to current clinical practice and guidelines. However, the patient was not eligible for 177Lu-DOTATATE peptide receptor radionuclide therapy and underwent 68Ga-FAPI04 PET/CT to assess the potential for a FAP-targeted therapy.

We investigated the role of PSMA-derived tumor burden in predicting docetaxel (DTX) therapy response in metastatic castration-resistant prostate cancer (mCRPC). Fifty-two mCRPC patients who received at least six cycles of DTX as the first-line treatment following 68Ga-PSMA PET/CT were enrolled in this retrospective study. Total PSMA-derived tumor volume (TV-PSMA) and total lesion PSMA activity (TL-PSMA) were derived from metastatic lesions. A ≥ 50% decline in PSA was defined as a response; a ≥ 25% increase in PSA was defined as progression. Univariate/multivariate logistic and cox regression analyses were performed to predict PSA response, OS, and TTP. Twelve (23%) patients had PSA progression after chemotherapy, while 40 patients (77%) achieved a PSA response. On univariate analysis, a significant association was found between TV-PSMA (p = 0.001), TL-PSMA (p = 0.001), pre-PSA (p = 0.012), LDH (p = 0.003), Hg (p = 0.035), and PSA response to DTX. High TV-PSMA (> 107 cm3) (p = 0.04) and high LDH (> 234 U/L) (p = 0.017) were 8.2 times and 12.2 times more likely for DTX failure in multivariate regression analyses. The median TTP was 16 months, and the median OS was not reached. Patients with high TV-PSMA (p = 0.017), high TL-PSMA (> 1013 cm3) (p = 0.042), high age (> 70 years) (p = 0.016), and high LDH (p ≤ 0.001) had significantly shorter OS, while only high TV-PSMA (p = 0.038) and high age (p = 0.006) were significantly related with shorter TTP. High TV-PSMA (p = 0.017) and high age (p = 0.01) were significant predictors for shorter OS, while only high age (p = 0.006) was a significant predictor for shorter TTP in multivariate analysis. Patients with high TV-PSMA had a significantly higher risk for DTX failure. PSMA-based tumor burden prior to DTX therapy seems to be a reliable predictive tool for survival in mCRPC patients.

68Ga-prostate-specific membrane antigen (PSMA) PET/CT is a well-established imaging modality in patients with prostate cancer; however, PSMA expression is also reported in the tumor-associated neovasculature, including but not limited to hepatocellular carcinoma, breast cancer, and renal cell carcinoma. Herein, we present 2 patients diagnosed with different histopathological subtypes of renal cell carcinoma who underwent 68Ga-PSMA PET/CT before surgery. Both cases have different PSMA expression characteristics and are presented along with pathological findings.

Background Peptide receptor radionuclide therapy and selective internal radiation therapy are effective radionuclide therapy modalities for unresectable metastatic neuroendocrine tumor patients that cannot be controlled with somatostatin analogs. The present study is intended to evaluate the therapeutic efficacy and toxicity of the combined therapy of selective internal radiation therapy and peptide receptor radionuclide therapy and stand-alone selective internal radiation therapy in patients with neuroendocrine tumor, a liver-dominant disease. Methods This cohort consists of 27 patients with metastatic neuroendocrine tumor and liver-dominant disease. They were grouped as the patients who were treated with selective internal radiation therapy for unresectable liver metastasis (n = 15) and the patients who received a combination of selective internal radiation therapy and peptide receptor radionuclide therapy (n = 12) for hepatic and extrahepatic metastasis. Treatment efficacy and treatment-associated toxicity were retrospectively assessed in both groups. Results The objective treatment response and stable disease were found in 13 patients (86.6%) in the selective internal radiation therapy group and eight patients (66.6%) in the selective internal radiation therapy + peptide receptor radionuclide therapy group. The median overall survival rate was found to be 34.9 months, in the selective internal radiation therapy group and 67.5 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.217). The median progression-free survival data was not reached, and the mean values of progression-free survival were 53.1 ± 9.9 months in the selective internal radiation therapy group, and 27.2 ± 5.9 months in the selective internal radiation therapy + peptide receptor radionuclide therapy group (P = 0.561). Temporary lymphopenia was the most common side effect. Grade 1-2 hepatotoxicity was observed to be 6.6% in the selective internal radiation therapy group, while it was not observed in selective internal radiation therapy + peptide receptor radionuclide therapy group. Conclusions In the neuroendocrine tumors with liver-dominant metastatic disease, personalized selective internal radiation therapy and peptide receptor radionuclide therapy and their combinations result in increased survival rates. Selective internal radiation therapy alone could be an effective treatment in patients with liver-limited and -dominant disease.

Amaç: Bu çalışmanın amacı, malign ve benign plevral hastalığın ayırıcı tanısında 18F-FDG PET/BT’nin performansı ve malign plevral mezotelyomadaki (MPM) prognostik değerini incelemektir. Yöntem: Konvansiyonel BT’de saptanan diffüz ya da nodüler plevral kalınlaşma nedeniyle 18F-FDG PET/BT çekilen 58 hasta retrospektif olarak incelendi. 18F-FDG PET/BT taramaları, maksimum standartlaştırılmış uptake değeri (SUVmax) kullanılarak görsel ve yarı kantitatif olarak değerlendirildi. Pozitif/negatif tutulum ayrımında eşik değeri olarak mediastinal kan havuzu SUVmax değerleri kullanıldı. 18F-FDG PET/BT bulguları, histopatolojik bulgular ve sağkalım verileri ile karşılaştırıldı. Hastalar klinik ve radyolojik olarak takip edildi. Bulgular: 58 hastanın 38’inde (%65,5) plevral lezyonlar FDG pozitifti; 28/38 hastada (%73,6) MPM ve 10/38 hastada (%26,4) benign plevral hastalık tanısı histopatolojik olarak saptandı. Negatif 20/58 taramanın (%34,5) 18’i iki yıllık takip ile benign hastalık kabul edilirken radyolojik progresyon saptanan 2 hastaya MPM tanısı kondu. Duyarlılık, özgüllük, doğruluk, pozitif prediktif ve negatif prediktif değerler sırasıyla %93, %64, %79, %73 ve %90 idi. Ortanca genel sağkalım süresi 14,5 ay olarak bulundu. Daha yüksek SUVmax düzeyi (SUVmax> 7,4), daha kısa sağkalım ile ilişkili bulundu (13 ay; 24 ay) (p=0,032). Sonuç: 18F-FDG PET/BT, malign/benign plevral lezyonların ayırıcı tanısı için duyarlı bir görüntüleme yöntemi olup biyopsi hedefinin belirlenmesi ve hastaların yönetiminde etkilidir. MPM SUVmax değeri prognozu öngörme potansiyeline sahiptir., Objective: The purpose of this study is to evaluate the performance of 18F-FDG PET/CT in the differential diagnosis of malignant and benign pleural disease as well as its prognostic value in the malignant pleural mesothelioma (MPM). Methods: Fifty-eight patients who underwent 18F-FDG PET/ CT due to diffuse or nodular pleural thickening determined on conventional CT were retrospectively analyzed.18F-FDG PET/ CT scans were evaluated visually and semiquantitatively using maximum standardized uptake value (SUVmax). Mediastinal blood pool SUVmax was used as a threshold value for defining positive/negative accumulation of tracer. 18F-FDG PET/CT findings were compared with histopathological and survival data. Patients were followed up clinically/radiologically. Results: Thirty-eight of fifty-eight patients (65.5%) had FDG (+) pleural lesions; 28/38 patients (73.6%) were diagnosed MPM and 10/38 patients (26.4%) were determined benign pleural disesase histopathologically. 20/58 scans (34.5%) were negative, and 18 of them were assumed benign based on two years follow-up, whereas 2 patients were diagnosed MPM by biopsy due to radiologic progression. Sensitivity, specificity, accuracy, positive predictive, and negative predictive values were 93%, 64%, 79%, 73%, and 90% respectively. Median overall survival was found to be 14.5 months. Higher SUVmax level (SUVmax>7.4) was associated with shorter survival (13 vs. 24 months)(p=0.032). Conclusion: 18F-FDG-PET/CT is a sensitive imaging method for differential diagnosis of malignant/benign pleural lesions, indicates the target of biopsy, and effects the management of patients. SUVmax of MPM has a potential role for predicting the prognosis.

In nuclear medicine practice, there have been many diagnostic tools developed for primary detection, staging, and evaluation of treatment response in breast cancer. Although recent developments in breast imaging have been achieved, especially in positron emission tomography (PET) systems, conventional nuclear medicine imaging methods, including bone scintigraphy and sentinel lymph node (SLN) scintigraphy, still have important roles in the management of breast cancer. Radionuclide therapies, which have constituted a large part of nuclear medicine practice in recent decades, also offer both palliation and longer survival in breast cancer patients. This chapter outlines the role of nuclear medicine both in imaging and the treatment of patients with breast cancer.

We aimed to demonstrate the role of SPECT/CT in preoperative localization of parathyroid lesions in patients with hyperparathyroidism who had technetium-99m (Tc-99m) methoxyisobutylisonitrile (MIBI) dual-phase parathyroid scintigraphy. We evaluated retrospectively the scintigraphic data of 103 patients who had parathyroidectomy after Tc-99m MIBI dual-phase parathyroid scintigraphy with SPECT/CT. The planar and SPECT/CT images were evaluated separately to determine their efficacy in localizing parathyroid lesions. These results were then compared with surgical data. There were 84 female and 19 male patients whose mean age was 54 ± 12 years. A total of 115 parathyroid lesions in 103 patients were resected during operations. In 87 patients, with both planar and SPECT/CT images, a total of 100 lesions could be detected correctly. In 11 patients, only SPECT/CT images could show 13 subcentimetric lesions. In three patients, three lesions were evaluated as parathyroid lesions both with planar and SPECT/CT images, but according to histopathologic evaluation, they came out to be nonparathyroidal lesions. In two patients, two parathyroid lesions could not be detected preoperatively neither with planar nor with SPECT/CT images. The lesion-based sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 87 %, 99 %, 97.1 %, 95.3 %, and 95.8 % for planar images and 98.3 %, 99 %, 97.4 %, 99.4 %, and 98.8 % for SPECT/CT images, respectively. Tc-99m MIBI parathyroid scintigraphy should be a diagnostic modality of choice in preoperative evaluation of patients with hyperparathyroidism. SPECT/CT has an incremental value both in demonstrating subcentimetric lesions and in accurately localizing lesions anatomically.

We aimed to investigate the SUVmax of primary tumor and metastatic lymph node in predicting survival in patients with esophageal cancer.We retrospectively analyzed patients with esophageal cancer between 2009 and 2011 who had FDG positron-emission tomography (PET)/computed tomography (CT). All patients were followed-up to 2013. Clinical staging, SUVmax of primary tumor and metastatic lymph node were evaluated.One hundred seven patients were included in the study. All patients were followed-up between 2 and 49 months. The mean SUVmax of primary tumor and metastatic lymph node were 19.3±8.8 and 10.4±9.1, respectively. Metastatic lymph node SUVmax had an effect in predicting survival whereas primary tumor SUVmax did not have an effect (p=0.014 and p=0.262, respectively). Multivariate Cox regression analysis showed that clinical stage of the disease was the only independent factor predicting survival (p=0.001).Among patients with esophageal cancer, the value of primary tumor SUVmax did not have an effect on survival. Clinical stage assessed with FDG PET/CT imaging was found to predict survival in esophageal carcinoma. Additionally, lymph node SUVmax was identified as a new parameter in predicting survival in the present study.Amaç: Çalışmamızda özofagus kanserli hastalarda primer tümör SUDmax ve metastatik lenf nodu SUDmax’ın sağ kalım üzerine olan etkisini araştırmayı amaçladık. Yöntem: 2009 ve 2011 yılları arasında evreleme amacıyla FDG pozitron emisyon tomografisi (PET)/bilgisayarlı tomografi (BT) yapılan özofagus kanseri tanılı hastalar retrospektif olarak incelendi. Tüm hastalar Eylül 2013 yılına kadar takip edildi. Histopatoloji, lokalizasyon, klinik evre, primer tümör ve metatastatik SUVmax kaydedildi. Tanımlanan parametreler arasındaki ilişkiler ve sağ kalım univaryant ve multivaryant Cox regresyon analizi ile değerlendirildi. Bulgular: Çalışmaya 107 hasta dahil edildi. Hastaların hepsi 2-49 ay arasında takip edildi. Primer tümör ve metastatik lenf nodu ortalama SUDmax sırasıyla 19,3±8,8 ve 10,4±9,1 olarak hesaplandı. Metastatik lenf nodu SUDmax sağ kalım üzerine etkili iken primer tümör SUDmax’ın sağ kalım üzerine etkisi olmadığı görüldü (p=0,014 ve p=0,262, sırasıyla). Klinik evrenin sağ kalımı belirlemede multivaryant Cox regresyon analizi ile sağ kalımı belirlemede bağımsız tek faktör olduğu görüldü (p=0,001). Sonuç: Özofagus kanseri tanılı hastalarda primer tümör SUDmax’ın sağ kalım üzerine etkisi olmadığı görüldü. FDG PET/CT ile belirlenen klinik evrenin sağ kalımı belirlediği görüldü. Ayrıca çalışmamızda metastatik lenf nodu SUDmax’ın sağ kalımı öngörmede yeni bir parametre olabileceği görülmektedir.

A 52-year-old woman diagnosed with mycosis fungoides was referred for F-FDG PET/CT before treatment for the evaluation of disease severity. The patient also underwent Ga-pentixafor PET/CT for further evaluation. FDG uptake was observed in cervical, axillary, and pelvic lymph nodes and multiple widespread skin lesions throughout the body, suggestive of extensive involvement of mycosis fungoides. All lesions were visually identifiable with high target-to-background ratio on Ga-pentixafor PET/CT which demonstrated marked CXCR4 expression in all lesions that were detected using F-FDG PET/CT.

PurposeWe aimed to compare the efficacies of gallium-68 (68Ga) DOTATATE PET-computed tomography (CT), fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT and technetium-99m (99mTc)-(V)DMSA scintigraphy in the detection of residual/metastatic medullary thyroid carcinoma (MTC).Materials and methodWe retro

DOI: 10.26650/IUITFD.345626Objective: The aim of this study was toinvestigate the contribution of SPECT-CT to planar imaging in patients withdifferentiated thyroid carcinoma (DTC) following radioiodine therapy.Materials and Methods: Post-therapy scanwas performed on 325 patients (254 women, 71 men; age range 15-81 years) whowere operated on for DTC and treated with radioactive iodine (100-200 mCi)therapy. Whole-body planar imaging and neck–chest planar + SPECT-CT imagingwere performed on all patients. Additional SPECT-CT scans were performed inother areas where suspicious findings were observed on the planar images. Theiodine-positive areas on the planar images were classified as benign,equivocal, or malignant and were also reevaluated by two nuclear medicinephysicians using SPECT-CT images. The final diagnosis was verified byhistology, other imaging modalities, and clinical–serological follow-up.Results: Based on patient-based analysis,SPECT/CT altered the interpretation of the planar scans by detecting thefollowing findings: additional metastatic lymph nodes in 21 (21/50) patients,lung metastases in 2 (2/10) patients, and bone metastases in 2 (2/12) patients.Furthermore, SPECT/CT confirmed that equivocal focal uptakes were benign in 83patients and malign in 48 patients. The sensivity, specificity, positivepredictive value, negative predictive value, and accuracy were 63.4%, 92.7%,67.7%, 91.3%, and 87%, respectively, for the planar imaging and 96.8%, 100%,100%, 99.2%, and 99.3%, respectively, for the SPECT-CT imaging. Overall,SPECT-CT affected therapy management in 76 patients (23.3%).Conclusion: SPECT-CT imaging improvesdiagnostic accuracy by reducing false-negative or -positive results in planarimaging in the post-therapy scan in patients with DTC. Our findings suggestthat neck-thorax SPECT-CT imaging should be incorporated into the routineimaging protocol for detecting the most metastatic sites of DTC., DOI: 10.26650/IUITFD.345626Amaç: Bu çalışmada differansiye papillertiroid kanseri (DTK) olan hastalarda tedavi sonrası görüntülemede SPECT-BT’ninplanar görüntülemeye katkısını araştırdık. Gereç ve Yöntem: DTK tanısı ile opere olanve radyoaktif iyot tedavisi (100-200mCi) uygulanan toplam 325 hastaya tedavi sonrası görüntüleme yapıldı (254kadın, 71 erkek; yaş aralığı: 15-81). Tüm hastaların tüm vücut planar ileboyun-toraks bölgesinden planar + SPECT-BT görüntüleri alındı. Ek olarak planargörüntülerde şüpheli tutulum saptanan alanlardan SPECT-BT görüntüleme yapıldı.Planar görüntülemede benign, şüpheli ve malign olarak sınıflandırılan iyotpozitif alanlar iki nükleer tıp uzmanı tarafından SPECT-BT görüntüleri ileyeniden değerlendirildi. Nihai tanı histoloji, diğer görüntüleme yöntemleri,klinik-serolojik takipler ile doğrulandı. Bulgular: Hasta bazlı sonuçlara göreSPECT-BT planar görüntülemeye ek olarak 21 (21/50) hastada metastatik lenfnodları, 2 (2/10) hastada akciğer metastazları, 2 (2/12) hastada kemik metastazlarıtespit ederek; 83 hastada benign, 48hastada malign olmak üzere şüpheli tutulumları açıklığa kavuşturarak planargörüntüleme yorumunu değiştirdi. Duyarlılık, özgüllük, pozitif prediktif değer, negatif prediktif değerve doğruluk planar görüntüleme için sırasıyla %63,4, %92,7, %67,7, %91,3, %87iken SPECT-BT için sırasıyla % 96,8, % 100, %100, %99,2 ve %99,3 olarakhesaplandı. SPECT-BT toplamda 76 hastanın (%23,3) tedavi yönetimini etkiledi.Sonuç: SPECT-BT görüntüleme, DTChastalarında tedavi sonrası taramada planar görüntülemenin yanlışnegatif/pozitif sonuçlarını azaltarak tanısal doğruluğu artırmaktadır.Sonuçlarımız DTC’nin en sık metastaz yaptığı boyun ve toraks bölgesinindeğerlendirilmesinde SPECT-BT görüntülemenin rutin görüntüleme protokolünealınmasını önermektedir.

Objective: We aimed to evaluate the value of somatostatin receptor imaging (SRI) with In-111 octreotide and Ga-68 DOTATATE in localizing ectopic ACTH producing tumors. Methods: Nineteen patients who had In-111 octreotide somatostatin receptor scintigraphy (SRS) and/or Ga-68 DOTATATE PET-CT to localize ectopic ACTH producing tumors between the years 2000 and 2012 were included retrospectively in our study. The results of SRI were compared with clinical onset, radiological findings and surgical data of the patients. Results: Sixteen In-111 octreotide SRS and five Ga-68 DOTATATE PET-CT were performed in 19 patients. In eight out of 19 patients, ectopic ACTH secretion site could be detected. In five patients, SRS showed pathologic uptake. In four of these patients, surgery revealed pulmonary carcinoid tumors and in one patient pancreatic neuroendocrine tumor. In one patient, Ga-68 DOTATATE PET-CT revealed pathologic uptake in lung nodule which came out to be pulmonary carcinoid tumor. In another patient who had resection of metastases of atypical carcinoid tumor prior to scans, new metastatic foci were detected both with SRS and Ga-68 DOTATATE PET-CT imaging. In one patient, although SRS was negative, CT which was performed three years later showed a lung nodule diagnosed as pulmonary carcinoid tumor. In 11 patients, ectopic ACTH secretion site could not be detected. In 10 of those patients, scintigraphic and radiological imaging did not show any lesions and in one patient, Ga-68 DOTATATE PET-CT was false positive. Conclusion: SRI has a complementary role with radiological imaging in localizing ectopic ACTH secretion sites. PET-CT imaging with Ga-68 peptide conjugates is a promising new modality for this indication. Conflict of interest:None declared.

Tumor recurrence of colorectal cancers (CRC) is generally followed up by analyses of the serum carcinoembryonic antigen (CEA) levels. However, recent evidence suggests that tumor recurrence can also be visualized by 18F-fluoro-deoxyglucose emission tomography/computed tomography (FDG-PET/CT) in patients with normal CEA levels. We retrospectively evaluated the diagnostic performance of FDG-PET/CT in patients with suspected recurrence of CRC by comparing PET/CT performance in patients with normal CEA levels with PET/CT performance in patients with elevated CEA levels.A total of 235 patients with CRC who had been treated with surgery and/or chemotherapy/radiotherapy underwent PET/CT for the detection of tumor recurrence. The patients [96 females and 139 males; age (mean ± SD) 59.9 ± 12.6 years; range 18-85] were divided into 2 groups based on whether their CEA levels were normal (5 ng/ml) (Group 1, n = 118) or elevated (5 ng/ml) (Group 2, n = 117). All of the patients had suspected recurrence based on raised CEA levels, clinical symptoms, and/or tumor detection using other imaging modalities.Of the 235 patients, 172 (73.1 %) had disease recurrence confirmed by a pathological examination (either biopsy or surgical exploration) or clinical follow-up studies. The FDG-PET/CT study yielded a true positive in detecting recurrence in 169 (71.9 %) patients, a true negative in 53 (22.5 %) patients, a false negative in 3 (1.2 %) patients and a false positive in 10 (4.2 %) patients. CRC recurrence was detected in 64.4 % (76/118) and 88 % (103/117) patients in Group 1 and Group 2 with FDG-PET/CT, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the FDG-PET/CT study for establishing recurrence were 100, 84, 89.4, 100 and 93.2 %, respectively, for Group 1; by contrast, these parameters were 97.1, 84.6, 98, 78.5 and 95.7 %, respectively, for Group 2. The number of patients with hepatic and extra-hepatic metastases, such as lung and abdominal lymph node metastasis, detected with FDG-PET/CT was significantly different in Group 1 than in Group 2; however, the number of patients with local recurrence and peritoneal implants detected with FDG-PET/CT was not different between the two groups.FDG-PET/CT can accurately detect tumor recurrence in patients with suspected recurrent CRC, even for patients with normal CEA levels.

BACKGROUND We aimed to evaluate the role of Tc-99m labeled red blood cell (RBC) scintigraphy for determination of localization of gastrointestinal system (GIS) bleeding. METHODS Fifty-seven cases (27 females, 30 males; mean age 43.9±24; range 1 to 91 years) who referred to our clinic between 1995-2010 were evaluated for determination of localization of GIS bleeding with RBC scintigraphy. Prior to scintigraphy, gastroscopy in 51, colonoscopy in 45, and angiography in 9 patients were performed. RESULTS RBC scintigraphies were positive and negative in 31 and 26 patients, respectively. Positive scintigraphic findings were obtained within the 1st hour of dynamic imaging in 19 patients, within the 1st-4th hour static images in 7, and within the 4th-24th hour images in 5 patients. Fourteen patients underwent surgical exploration. In 13 patients, the surgery confirmed the diagnosis by RBC scintigraphy (accuracy: 92.8%). Of 43 patients without surgical exploration, 12 had anemia due to iron deficiency and their scintigraphic evaluation were negative. Four patients died and in 27 patients, GIS bleeding ceased spontaneously or with conservative measures. CONCLUSION Scintigraphy should be the primary tool for accurate diagnosis of patients with active GIS bleeding. Positive dynamic images obtained within the first hour of imaging may be more accurate for demonstrating bleeding localization and a good predictor of requirement of surgical exploration.

Objective: The aim of this prospective study was to evaluate the additional value of Tc 99m HMPAO white blood cell (WBC) SPECT for bone and soft tissue infections. Materials and Methods: Thirty-eight patients with suspected bone and joint infection were included in the study. Patients were assigned into 2 groups according to the presence of orthopedic implants. All patients had multiphase bone scan (BS) with Tc 99m methylene diphosphonate and WBC scintigraphy. The planar images of BS and WBC images were evaluated together. SPECT WBC images were evaluated separately. Results: Group 1 had 30 patients including 12 patients with diabetic foot, 17 patients with suspected relapse of chronic osteomyelitis and 1 with septic arthritis. In 19 of 30 patients, BS and planar WBC images were similar with SPECT images in terms of final diagnosis. In the remaining 11 patients, planar BS+planar WBC images and SPECT WBC images were discordant. Group 2 included 8 patients with suspected infection of orthopedic implants. There was no difference between planar BS+planar WBC images and SPECT WBC in 6 of 8 patients. SPECT WBC images changed the diagnosis of 13 (34.2%) patients in the whole group. SPECT WBC images did not have any contribution in the evaluation of the 6 patients who had reactive changes. Conclusion: SPECT images made significant contribution in discriminating soft tissue infection from osteomyelitis and improved diagnosis in terms of localization and the extent of disease. Conflict of interest:None declared.

The objective of this study is to determine the range of SUVmax of 68Ga-DOTATATE in normal organs and tumoral lesions and establish uptake unrelated to NET. One hundred and twenty patients (57 men, 63 women), who underwent 68Ga-DOTATATE PET/CT imaging in our institution were analyzed. Patients were indicated for 68Ga-DOTATATE PET/CT imaging to detect primary tumor or metastasis of suspected or previously known NET, to determine SSTR positivity and to detect occult source of ectopic Cushing syndrome. Normal range of uptake was calculated for the organs that were proven to have no pathology by either conventional radiological imaging or clinical follow-up, using SUVmax as a semiquantitative measure. Uptake and tumor to background (T/B) ratios of tumoral lesions in liver, pancreas, bone, brain and lymph nodes were calculated. Uptakes due to lesions unrelated to NET were also documented. Significant uptake was found in spleen, kidneys, adrenal glands, liver and pituitary gland with mean SUVmax of 24.67, 14.30, 13.73, 9.12 and 9.74 respectively. Uptake was measured separately for the pancreatic head and body separately, however, besides a slightly heterogeneous uptake; the difference was not statistically significant. Uptake in the tumoral lesions had high (T/B) ratios with mean SUVmax of 28.72, 25.21, 18.28, 34.73 and 12.59 for liver, pancreas, bone, brain and lymph nodes, respectively. Incidental benign tumoral lesions were detected in 3 patients (2.5 %) which were meningioma and fibrous dysplasia demonstrating significant and breast fibroadenoma demonstrating mild 68Ga-DOTATATE uptake. Non-neoplastic processes were detected in 4 patients (14.1 %), including postsurgical inflammation, reactive lymph nodes, arthritis and demonstrated faint to mild 68Ga-DOTATATE uptake, with the exception of significant uptake in accessory spleen. 68Ga-DOTATATE has high T/B ratio with physiological biodistribution comparable to its counterparts. However, the presence of SSTRs in benign and malignant lesions unrelated to NET may be challenging in interpretation particularly where the physiological uptake is variable.

Hepatic adenomatosis is an uncommon benign neoplasm, with the presence of multiple adenomas (generally more than 4) within the liver. A 52-year-old woman presented with multiple (>10) solid liver lesions detected with abdominal ultrasonography and verified with magnetic resonance imaging (MRI). Subsequently, F-18 FDG PET/CT demonstrated increased uptake in these lesions. Histology revealed hepatic adenomatosis. F-18 FDG PET/CT cannot reliably differentiate hepatic adenomas from malignant processes on the basis of uptake.

Pulmonary carcinoid (PC) tumors are rare neoplasms of the lung with good prognosis but diagnosis may be demanding since there is no exclusive modality alone to clearly differentiate a PC tumor. The purpose of this study is to establish the diagnostic features of somatostatin receptor scintigraphy (SRS), comparatively (where available) with 18FDG PET/CT (PET/CT) correlated with histopathologic findings.Twenty-one patients who underwent SRS with 111In-octreotide and were diagnosed as having PC tumors were retrospectively studied. Thirteen patients were performed PET/CT. Primary tumour size, Ki-67 indexes, image analysis data of SRS and PET/CT including maximum standardized uptake values (SUVmax) together with false negative, false positive, true positive and true negative lesions were documented and discussed.Eleven (52.4%) patients were typical (TC) and 10 (47.6%) were atypical carcinoids (AC) with mean Ki-67 indexes of 2.1 and 24%, respectively. Patients underwent SRS for solitary pulmonary nodule (SPN) characterization (n = 12) and determination of disease extension (n = 9). Overall sensitivity and specificity of SRS in the detection of primary tumour, lymph nodes (LN) and distant metastasis (DM) were 76 and 97 %, respectively, whereas, positive and negative predictive values were 95 and 86 %. PET/CT was performed for determining disease spread (n = 3) and metabolic characterization (n = 10) of SPNs. Mean SUVmax in the primary pulmonary lesion in TCs and ACs were 2.9 ± 0.8 and 7.9 ± 5.4, respectively. Nodal involvement (n = 5) and DM (n = 3) were also detected. Sensitivity and specificity of PET/CT in the detection of primary tumour, LNs and DM were 85 and 89.4 %, respectively.SRS is useful in the diagnosis and monitoring of PC tumors when incorporated with 18FDG PET/CT as a primary staging tool particularly in the determination of disease spread.

To evaluate the relationship between FDG uptake and prognostic factors of breast cancer such as hormone receptors (estrogen and progesterone), expression of c-erbB-2, axillary lymph node status, tumor histology, grade and size.Between May 2009 and February 2011; 79 patients (mean age ± SD: 52.9 ± 13.9 years) with biopsy proven breast cancer underwent F-18 FDG PET/CT scanning for staging. Patients with excisional biopsy or neoadjuvant chemotherapy were excluded from the study. Histological types included were invasive ductal carcinoma (n = 68), invasive lobular carcinoma (n = 2), and invasive ductal plus lobular mixed carcinoma (n = 9). Maximum standardized uptake values (SUVmax) were compared with estrogen (ER) and progesterone receptors (PR), expression of c-erbB-2, as well as tumor grade and tumor size. For the evaluation of relationship between tumor SUVmax values and prognosticators such as hormone receptors, tumor histologic grade, and tumor size, statistical analyses were performed using Student t test, Mann-Whitney U Test and Pearson correlation coefficient and p values of less than 0.05 were considered to indicate statistically significant differences.All primary breast neoplasms were detected by PET/CT scanner. The mean SUVmax values and breast cancer tumor sizes ranged from 2.09 to 39.0 and 0.7 to 10 cm, respectively. Tumors with negative ER [(n = 19); SUVmax median (min-max): 15 (2.09-39.0)] were associated with higher SUVmax values (p = 0.01). Tumors with overexpression of C-erbB-2 [(n = 28); SUVmax median (min-max): 16.0 (5.0-39.0)]; tumor grade 3 [(n = 25); SUVmax median (min-max): 15 (6.43-39)]; axillary lymph node involvement [(n = 60); SUVmax median (min-max): 13.61 (4.0-39.0)]; tumor histopathology and increased tumor size were associated with higher maximum standardized uptake values. However, PR did not show any relationship with SUVmax values.In the present report, strong relationships were detected between the negativity of ER, overexpression of c-erbB-2, tumor grade, tumor size, histopathology, axillary lymph node involvement and SUVmax values. Accordingly, we believe that SUVmax values obtained with (18)F-FDG PET/CT may provide some information about tumor biology of breast cancer.

Echinococcosis is endemic in certain parts of the world, including Turkey. When the pulmonary cyst has characteristic features, it can be easily diagnosed, but when the appearance changes as a result of complications, the cyst may resemble a malignant lesion. We presented a complicated pulmonary hydatid disease patient who was referred to our department for PET–CT, after the detection of 2 lung lesions.

Lymphoma presenting with enlarged adrenal glands is not common. According to the literature, most adrenal lymphomas do not have extra-adrenal sites. We examined a 47-year-old male patient because of abdominal pain-an unusual presentation of adrenal lymphoma. Following ultrasonographic examination that showed bilateral massively enlarged adrenal glands, the patient underwent F-18 FDG PETCT. Written informed consent was obtained from the patient prior to PET-CT examination. PET-CT showed bilateral enlarged adrenal glands (right: 67×55 mm; left: 28×68 mm) and increased FDG uptake (SUVmax: 27-25) (Figure 1a). Additional foci of increased FDG accumulations were observed, as follows: in the millimetric parenchymal nodule on the middle lobe and in the parenchyma (with groundglass density) on the lower lobe of the right lung (Figure 1b); in pleural surfaces on the right hemithorax (Figure 1c); in peripancreatic and para-aortic lymph nodes in the abdomen-the largest of which was 3 cm in diameter (Figure 1d); in the right caput humeri and in the corpus of 4. lumbar vertebra (Figure 1e). All of these uptakes were in the range of malignant disease. CT-guided biopsy of the right adrenal gland showed diffuse large B cell lymphoma, which is the most common type of adrenal lymphoma. Most patients with adrenal lymphoma present with bilateral enlarged adrenal masses, without evidence of extra-adrenal spread [1,2]. Although some patients have extra-adrenal involvement [3-5], the presented patient had highly disseminated disease. The presence of multiple extranodal sites in lymphoma patients at presentation is associated with poor prognosis [4]. Generally, the response to chemotherapy is not good in such patients [5]. After the presented patient completed 3 cycles of R-CHOP chemotherapy, PET-CT showed that all previous hypermetabolic foci were normalized (Figure 2a-c) and that there were new foci of uptake in the interhemispheric area, in the frontal and right temporal lobes of the cerebrum (Figure 2d), in various vertebral bodies (Figure 2e), and in the intramedullary space between 1. and 2 lumbar vertebrae (Figure 2f). Patients with adrenal lymphoma have a tendency for late central nervous system involvement, as the