جستجوی مقالات مرتبط با کلیدواژه « FDG PET » در نشریات گروه « پزشکی »

Peritoneal carcinomatosis (PC), the spread of cancer cells in the peritoneum, is a significant concern in advanced gastrointestinal and gynecological cancers. This case series includes findings on the appearance and pattern of PC on 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT). The primary sources of peritoneal dissemination are direct invasion from abdominal or pelvic tumors and metastatic spread from distant tumors. The accurate preoperative diagnosis and quantification of PC play a vital role in determining the appropriate treatment approach, with a particular emphasis on surgical planning. Several imaging modalities have been employed in preoperative evaluation, such as computed tomography (CT), magnetic resonance imaging (MRI), and 18F-FDG PET/CT. Among these modalities, 18F-FDG PET/CT has demonstrated improved anatomical localization and accurate information about the nature of pathological findings. The case series showcases four cases that illustrate the imaging characteristics of PC on FDG PET/CT. FDG PET/CT plays a vital role in diagnosing and assessing PC, aiding in its detection, staging, and treatment planning. It surpasses conventional imaging techniques in identifying and characterizing lesions and detecting the primary tumor site in cases where its location is unknown. Furthermore, FDG PET/CT additionally assists in evaluating treatment response and monitoring disease progression, providing insights into treatment effectiveness and guiding patient management decisions.

 Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan is employed for initial staging and restaging of esophageal cancer patients.

 The present study aimed to assess the value of a semi-quantitative parameter of 18F-FDG PET/CT scan, that is, maximum standardized uptake value (SUVmax), to determine its correlation with patient survival in two subtypes of esophageal cancer, including squamous cell carcinoma (SCC) and adenocarcinoma.

 This cross-sectional study was performed on patients with esophageal SCC and adenocarcinoma, undergoing 18F-FDG PET/CT scan for initial staging before any treatment. The 18F-FDG PET/CT semi-quantitative parameter (SUVmax) was determined by reviewing the PET/CT images. The patients were reevaluated using 18F-FDG PET/CT scan for restaging within 12 - 24 months.

 No significant difference was observed in the SUVmax values of the primary tumor, metastatic lymph nodes, or distant metastasis between the adenocarcinoma and SCC groups, regardless of response to treatment. Similarly, no significant association was found between the short-term survival of patients with adenocarcinoma and the SUVmax values of the primary tumor, metastatic lymph nodes, or distant metastasis. Based on the survival curve, one- and two-year survival rates were estimated at 75% and 63.9% in patients with SCC and at 80% and 60% in patients with adenocarcinoma, respectively. In the SCC group, a significantly higher SUVmax was detected in deceased patients with distant metastatic lesions compared to cancer survivors. According to the area under the ROC curve, the SUVmax of metastatic lesions showed high potential for predicting the mortality of SCC patients.

 The assessment of SUVmax in distant metastatic lesions by 18F-FDG-PET/CT may help predict the survival of patients with esophageal SCC. However, 18F-FDG-PET/CT findings were not associated with the survival of esophageal adenocarcinoma; therefore, further evaluations on a larger sample size and a longer follow-up are required.

To evaluate the predictive value of the 18F-FDG PET/CT parameters on the histopathological features, receptor expression status, and molecular proliferation markers in breast cancer. Also, to assess the effect of the normal breast parenchymal uptake (BPU) on primary breast cancer.

287 patients were included, 198 patients with breast cancer (BC) and 89 patients with the healthy breast control group (CG). The metabolic parameters of breast carcinoma were compared with immunohistochemical subtypes, Ki-67 expression status, tumor size, axillary nodal involvement, and distant organ metastasis. We also analyzed the BPU using a 1.5 cm3 volume of interest (VOI) in the BC and CG groups.

There was a positive correlation between primary tumor SUVmax and tumor size (p=0.001), high Ki-67 expression (p<0.001), axillary nodal involvement (p<0,001), distant organ metastases (p=0.026), ER and PR negativity, and HER2 positivity (p=0.000, 0.001, and 0.021, respectively). Furthermore, the change in mean SUVmax in molecular subtypes was statistically significant (p<0.001). In addition, the SUVmax measured 0.5 cm from the tumor in the same quadrant is higher than the opposite quadrant and contralateral breast, suggesting that the distance to the tumor increases, the FDG uptake decreases (p<0.001 and 0.001, respectively).

Strong relationships were detected between the ER and PR negativity, HER2-positivity, high Ki-67 expression, tumor size, axillary lymph node involvement, distant organ metastases, and SUVmax values. Therefore, we believe that metabolic parameters obtained with 18F-FDG PET/CT may provide relevant information about breast cancer tumor biology and suggest a potential role in identifying more aggressive behavior.

Celiac disease (CD) is a chronic immune-mediated enteropathy that is caused by both environmental (gluten) and genetic (human leukocyte antigen (HLA) and non-HLA genes) factors. Patients may be asymptomatic or exhibit atypical symptoms, necessitating a high index of suspicion for proper diagnosis.The evaluation of CD patients with 18F-FDG PET/CT imaging can be difficult, owing to the fact that this disease is inflammatory in nature. Typical 18F-FDG PET/CT gastrointestinal manifestations of celiac disease include increased multifocal or diffuse bowel uptake, whereas single short segmental uptake is rarely encountered; thus, awareness of this wide range of findings is important to guide physicians through proper management and outcome.We report a case of small intestine adenocarcinoma and known CD complaining of recent episodes of diarrhea and weight loss that had a suspicious small bowel wall thickening that corresponds to a short segmental hypermetabolic process on FDG PET/CT follow-up scan. The patient was then referred to the gastroenterology department and underwent a colonoscopy, a biopsy was taken that revealed CD and was negative for malignancy. Furthermore, 6 months later the abovementioned segmental FDG activity was completely resolved without any treatment received at the given time.

Most primary small cells carcinoma develop from the lung, and extra-pulmonary small cell carcinoma accounts for less than 5% of all small cell carcinoma cases. In the head and neck region, the most common sites are the larynx and salivary glands; however primary involvement of the palate is extremely rare. The extra-pulmonary small cell carcinoma is similar to its pulmonary counterpart regarding morphology, immunohistochemistry, and electron microscopy features and derives from pluripotential stem cells that develop neuroendocrine features. There is growing evidence regarding the ability of extra-pulmonary small cell carcinoma to arise from pluripotent basilar cells capable of divergent differentiation with the consequence of arising neuroendocrine phenotype as a trans-differentiation phenomenon in the progression of an organ-specific carcinoma. The differentiation between primary and metastatic extra-pulmonary small cell carcinoma is challenging. There is also no standard guideline for treatment as it is a rare occasion, and there is no consensus between radiation oncologists and cancer surgeons about the best treatment strategy. In this study, a very rare case of hard palate small cell carcinoma with neuroendocrine pathology features is presented. To our best of knowledge, this is the third case report of extra-pulmonary small cell carcinoma involving the palate in the literature review. Knowing the clinical presentation and pathology characteristics of such rare tumor in addition to follow-up outcome can be highly useful to establish a reliable guideline for hard palate small cell carcinoma management.

18F-FDG PET/CT is increasingly performed in patients with differentiated thyroid cancer. The aim of this study was to assess the clinical impact of 18FFDG PET/CT on the management of patients with differentiated thyroid carcinoma who had elevated serum thyroglobulin (Tg) and negative 131I whole body scan (WBS) . 67 patients with differentiated thyroid carcinoma were included in this study. The findings of 18F-FDG PET/CT imaging were compared with histopathology, follow up imaging, or clinical follow-up results. The diagnostic accuracy of 18F-FDG PET/CT was evaluated for the entire patient group and for those patients with stimulated serum thyroglobulin levels of less than 5, 5–10, and more than 10 pmol/L as well as for local recurrences and metastases sites. The impact of 18F-FDG PET/CT on therapeutic management was also evaluated. 30/67 patients had positive findings on 18F-FDG PET/CT; 28 were truepositive and 2 were false-positive. 18F-FDG PET/CT results were true-negative in36 patients and false-negative in 1 patient. The overall sensitivity, specificity, accuracy, PPV and NPV of 18F-FDG PET/CT were, 96.5%, 94.5%, 95.5%, 93.3%, and 97.2% respectively. Positive 18F-FDG PET/CT findings were directly correlated with stimulated serum thyroglobulin levels, 7.1% had Tg between 5–10, and 92.9% had Tg greater than 10 pmol/L. 18F-FDG PET/CT had a high or moderate impact on treatment management in 28 (41.8%) of patients. 18F-FDG PET/CT is able to improve diagnostic accuracy and have management impact in a therapeutically relevant way in patients with differentiated thyroid carcinoma who present with rising thyroglobulin level, negative 131I WBS, and clinical suspicion of recurrent disease.

Although 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is an established method for the staging of malignancies, benign lesions (e.g, active inflammatory lesions) often show increased metabolic activity. Herpes zoster is the clinical manifestation of the activation and replication of dormant varicella-zoster virus (VZV) in individuals with decreased cell-mediated immunity. Although the diagnosis of herpes zoster is clinical, it is sometimes observed incidentally during imaging for another disease. We describe the case of a 67-year-old Japanese female patient diagnosed with cervical cancer in whom FDG-PET/CT revealed herpes zoster manifestations: hypermetabolic cutaneous lesions in the buttock and pelvic lymph node involvement. The resected lymph nodes showed no malignant lesions but revealed lymphoid follicle formation, probably related to viral infection. There has been no report comparing FDG-PET findings of lymph nodes with histologic findings; the present findings are compatible with a clinically VZV-induced inflammatory reaction in regional lymph nodes, which increased FDG accumulation. Active infection with VZV displays increased FDG uptake in regional lymph nodes and may lead to incorrect malignant disease management in oncology. Misdiagnoses can be avoided by a careful interpretation by experienced nuclear medicine physicians as well as proper clinical evaluation.

An initial evaluation of non-small cell lung cancer (NSCLC) patients with 18F- fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan can modify treatment planning. We investigated the clinical significance of FDG PET/CT quantitative parameters (QPs) in NSCLC patients. We included 125 NSCLC patients for initial staging FDG PET/CT scan. The primary tumor (T), regional lymph node metastases (N), and distant metastases (M) were evaluated on FDG PET/CT images. QPs, including standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated separately for each T, N, and M lesion and also for the whole body. Statistical analysis through SPSS version 22 was used to evaluate the clinical significance of PET/CT QPs concerning primary tumor pathology characteristics, initial tumor stage, and patient’s prognosis. We followed the patients for 19.28 (±11.42) months. Considering primary tumor pathology, there was a significant difference in FDG PET/CT QPs, including primary tumor SUVmax (p=0.00), metastases SUVmax (p=0.014), whole-body MTV (p=0.045), and whole-body TLG (p=0.002). There was also a significant difference in QPs, including primary tumor SUVmax (p=0.00) and regional lymph node metastases SUVmax (p=0.048) when accounting for tumor initial stage. There was a significant prognostic value for the whole-body TLG (p=0.01) and a cut-off point of 568 was reached to differentiate better versus worse survival outcome. We demonstrated a statistically significant difference in FDG PET/CT QPs when accounting for primary NSCLC pathology characteristics and initial stage, as well as patient’s prognosis, and recommend incorporating QP values into clinical PET/CT reports.

To assess the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography combined with the computed tomography (18F-FDG PET/CT) in the detection of recurrent or residual urinary bladder cancer with meta-analysis.

We searched PubMed/MEDLINE, Embase, Web of Science, CBM, CNKI, VIP, and Wanfang data-bases through October 2019. Two reviewers independently screened the full articles. The imaging findings were confirmed by either histopathology or clinical follow-up. Sensitivity, specificity likelihood ratio and diagnostic odds ratio were pooled with 95 % confidence intervals (CI). Overall test performance was summarized by a sum-mary receiver operating characteristic (ROC) curve. The Meta-DiSc software (version 1.4) was used to perform the meta-analysis.

The meta-analysis included 7 studies. The pooled sensitivity and specificity of PET/CT for the detection of recurrent or residual urinary bladder cancer was 94.0% (95% CI: 91.0%–96.0%) and 92.0% (95% CI: 88.0%–95.0%), respectively. Positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 9.77 (95% CI: 4.91–19.41), 0.99(95% CI: 0.06–0.13) and 95.09 (95% CI: 47.96–188.53), respectively. When residual urinary bladder cancer was excluded, sensitivity changed slightly.

This meta-analysis suggested that the diagnostic accuracy of PET/CT was good in detecting recurrent or residual urinary bladder cancer.

The role of 18F-FDG PET/CT in patients with multiple myeloma (MM) and other plasma cell disorder is well known. Solitary plasmacytoma (SP), an extremely rare form within this entity that accounts for approximately 4% of plasma cell malignancies, can be classified as solitary bone plasmacytoma (SBP) or solitary extramedullary plasmacytoma (SEMP). EMP (extramedullary plasmacytoma) is a rare neoplasm characterized by the monoclonal proliferation of plasma cells outside the bone marrow. Breast and craniocerebral region are the uncommon sites of presentations of EMP and rarely reported in the literature. The most frequent site of presentation is upper airways. EMPs have similar pathogenesis as MM, however, they differ in management as they are radiosensitive in nature, and radiotherapy is the preferred treatment modality. As solitary EMP has a better prognosis than SPB with a lower conversion rate to MM, accurate staging is essential to plan the treatment. 18F-FDG PET/CT has higher sensitivity for treatment response evaluation. In the present case series, it is aimed to depict the role of 18F-FDG PET/CT in newly diagnosed solitary EMP with different sites of origin to exclude further lesions which lead to change in a treatment plan and in treatment response assessment.

Non-Hodgkin lymphoma (NHL) is a group of malignant lymphoproliferative disorders arising predominantly in the lymph nodes with various clinical and histological characteristics. At least 25% of NHL originates from tissues other than lymph nodes and sometimes even from sites that do not contain lymphoid tissue. These are referred to as primary extranodal lymphomas (pENLs). pENL is a universal diagnostic challenge to the clinicians and pathologists due to their varied clinical presentations, morphological mimicry, and molecular alterations. The GIT is the most common site of pENL followed by nasopharynx/oropharynx, testis, uterus/ovary, thyroid, and central nervous system. Long bones (tibia), maxillary sinus, skin, and paraspinal soft tissues are the other rare anatomic sites of pENL. We reported a case of a 60-year-old female presented with pain and mass in the pelvis region. 18F-Fluorodeoxyglucose(FDG) PET/CT was done, which revealed extensive extranodal involvement of the lung, bilateral kidneys, uterus, ovaries, bones, and muscles with no involvement of lymph nodes or lymphomatous organs. Extensive extranodal involvement with sparing of lymphomatous organ has not been reported earlier.

High-grade B-cell lymphoma, an aggressive form of Non-Hodgkin’s Lymphoma, is known as a double or triple hit lymphoma based on the presence of MYC and BCL2 without or with BCL6 genetic rearrangements, respectively. It carries a poorer prognosis, compared to other variants of B-cell lymphoma, and its management also differs which requires more intensive chemotherapy in contrast to the routine regimen. Terminal deoxynucleotidyl transferase (TdT), a marker of immaturity is commonly expressed in B-cell lymphoblastic leukemia or lymphoma (B cell ALL) which is absent in mature forms of B-cell lymphoma. The TdT is expressed in highgrade B-cell lymphoma; therefore, it poses a classification and management dilemma, which should be accurately differentiated from B-cell ALL and mandates molecular analysis. Herein, we report a case of a 52-year-old female with biopsy reported as high-grade B-cell lymphoma with TdT expression. She was referred for Fluor-deoxyglucose (FDG) Positron Emission Tomography-Computed Tomography (PET/CT) scan for staging in the absence of molecular analysis for Bcell ALL. It was diagnosed as lymphoma on FDG PET/CT based on its characteristic findings of extensive extranodal involvement of multiple organs with no significant lymphadenopathy establishing the incremental value of FDG PET/CT scan, which helped the clinician to arrive at a conclusion.

Functional imaging presents a non-invasive process that may capture the hyper-metabolic nature of red bone marrow in myeloproliferative neoplasms, such as polycythemia vera (PV).

This study analyzed the FDG-PET/CT scans (n=12) of six patients diagnosed with PV and six age-sex matched controls using a quantitative global analysis methodology.

All PV patients had elevated activities in the bone marrow of each skeletal structure as compared to matched controls with respect to mean standardized uptake value (femoral neck p=0.01, lumbar spine p=0.02, pelvis p=0.002, sternum p=0.04). Notable variations in splenic uptake were observed among the treated and untreated PV patients.  

Our study exemplifies the potential utility of PET in reflecting hyperactive bone marrow activity related to PV. Future studies may further substantiate and elaborate on the use of PET-derived metabolic data in PV.

Studies have reported that invasive ductal carcinoma (IDC) with coexisting ductal carcinoma in situ (DCIS) show lower metastatic potential and recurrence and better overall survival than pure IDC. In this study, we assessed F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) imagesof patients with newly diagnosed IDC to determine if there is any difference in PET findings in IDC-DCIS and pure IDC cases.
FDG PET/CT images of patients with newly diagnosed IDC of the breast who subsequently   underwent breast surgery and had histopathology result in our records were further evaluated. Tumor grade, pathological staging, and presence of DCIS were noted from the histopathology results. Standardized uptake value (SUV) of the primary tumor (SUVmax and SULmax), other hypermetabolic foci in the breast, and   ipsilateral normal breast were measured. Presence of axillary and distant metastases was noted.  
Fifty seven (57) patients with IDC were included. Coexisting DCIS was present in 44 (IDC-DCIS) and not present in 13 (pure IDC) cases.  Per histopathology, the primary tumor was unifocal in 33 IDC-DCIS (75%) and 12 pure IDC (92.3%) cases, and multifocal in 11 IDC-DCIS cases (25%), and 1 pure IDC case (7.7%). FDG uptake was multifocal in 20 IDC-DCIS cases (45.5%) and 1 pure IDC case (7.7%), and unifocal in 24 IDC-DCIS (54.5%), and 12 pure IDC (92.3%) cases. There was no significant difference in patient age, size of the primary tumor, SUVmax and SULmax of the primary tumor and SUVmax of the normal breast in IDC-DCIS and pure IDC cases (p>0.05). Pathology showed axillary metastasis in all 13 pure IDC (100%), and 27 IDC-DCIS (61.4%) cases. PET showed axillary uptake in 25 IDC-DCIS (56.8%), and 8 pure IDC (61.5%) cases, and abnormal/questionable distant uptake in 12 IDC-DCIS cases and 1 pure IDC case.
In our preliminary findings,multifocal breast FDG uptake and multifocal tumor appear to be more common inIDC-DCIS than pure IDC. There is no significant difference in SUV and size of the primary tumor in IDC-DCIS and pure IDC cases. Axillary metastases appear to be more common in pure IDC than IDC-DCIS cases.

Carcinosarcoma is a rare type of cancer that is composed of a mixture of sarcomatous and carcinomatous elements. Pulmonary carcinosarcoma has a 25% five-year survival rate with a prognosis poorer than other non-small cell lung carcinomas. Herein, we report a case of pulmonary carcinosarcoma and its 18F-FDG PET/CT findings. A 61-year-old male patient presented with brain symptoms, including headache, nausea, right hemiplegia, and few attacks of seizures. He underwent brain computed tomography (CT) scan showing a brain lesion in the left parietal lobe. The patient underwent excisional biopsy, and brain lesion was removed. The results of tissue sampling were indicative of carcinosarcoma. Based on anatomical imaging and evidence of pulmonary lesion, the patient underwent 18FDG PET/CT that revealed a heterogeneous mass on the upper lobe of the left lung. An intense FDG uptake was observed along the rim of the mass; however, no FDG uptake was observed in the center of the mass. There were multiple mediastinal lymph nodes with a high FDG uptake. Pulmonary carcinosarcoma was confirmed by tissue sampling.

        Regarding mediastinal N-staging in lung cancer patients, computed tomography (CT), magnetic resonance imaging (MRI), and integrated 18Fluorine-fluorodeoxyglucose-positron emission tomography/CT (18F-FDG-PET/CT) are the most widespread imaging methodologies in clinical routine. In order to further extract information from non-invasive staging, we evaluated the use of 18F-FDG-PET/CT and dynamic contrast enhanced (DCE) and diffusion-weighted imaging (DWI) MRI using histopathology as the diagnostic gold standard. Patients and A total number of 50 patients had undergone MRI of the chest within two weeks prior to surgery for histopathological proof. DCE-MRI was evaluated on the basis of region of interest (ROI)-based signal intensity/time (SI/T) curves in the respective mediastinal lymph nodes (LNs). In total, 28 LNs could be allocated to the corresponding histopathological findings, as well as to corresponding findings in 18F-FDG-PET/CT. Malignant LNs presented with significantly higher FDG uptake in PET. Significant differences between malignant and benign LNs were found for DCE-MRI regarding the parameters MaxE, 4-minutes value, SE, EP and EP/MaxE. In DWI-MRI, malignant LNs presented with significantly lower signal intensity compared to benign LNs (p < 0.01). An apparent diffusion coefficient (ADC) threshold of 1528 mm2/s was found to exclude malignancy for LNs that are above the threshold. 18F-FDG-PET in addition with MRI that includes DWI might improve mediastinal N-staging, which is of interest in cases of FDG-equivocal LNs. An ADC threshold of 1528 mm2/s might potentially help to further classify LNs with indefinite PET-findings. DCE-MRI of mediastinal LNs seems not yet to be approved for clinical routine.

Alternative normalization methods were proposed to solve the biased information of SPM in the study of neurodegenerative disease. The objective of this study was to determine the most suitable count normalization method for SPM analysis of a neurodegenerative disease based on the results of different count normalization methods applied on a prepared digital phantom similar to one obtained using fluorodeoxyglucose-positron emission tomography (FDG-PET) data of a brain with a known neurodegenerative condition. Digital brain phantoms, mimicking mild and intermediate neurodegenerative disease conditions, were prepared from the FDG-PET data of 11 healthy subjects. SPM analysis was performed on these simulations using different count normalization methods. In the slight-decrease phantom simulation, the Yakushev method correctly visualized wider areas of slightly decreased metabolism with the smallest artifacts of increased metabolism. Other count normalization methods were unable to identify this slightly decreases and produced more artifacts. The intermediate-decreased areas were well visualized by all methods. The areas surrounding the grey matter with the slight decreases were not visualized with the GM and VOI count normalization methods but with the Andersson. The Yakushev method well visualized these areas. Artifacts were present in all methods. When the number of reference area extraction was increased, the Andersson method better-captured the areas with decreased metabolism and reduced the artifacts of increased metabolism. In the Yakushev method, increasing the threshold for the reference area extraction reduced such artifacts. The Yakushev method is the most suitable count normalization method for the SPM analysis of neurodegenerative disease.

The aim of this study is to examine the effect of different smoothing filters on the image quality and SUVmax to achieve the guideline recommended positron emission tomography (PET) image without harmonization.
We used a Biograph mCT PET scanner. A National Electrical Manufacturers Association (NEMA) the International Electrotechnical Commission (IEC) body phantom was filled with 18F solution with a background activity of 2.65 kBq/mL and a sphere-to-background ratio of 4. PET images obtained with the Biograph mCT PET scanner were reconstructed using the ordered subsets-expectation maximization (OSEM) algorithm with time-of-flight (TOF) models (iteration, 2; subset, 21); smoothing filters including the Gaussian, Butterworth, Hamming, Hann, Parzen, and Shepp-Logan filters with various full width at half maximum (FWHM) values (1-15 mm) were applied. The image quality was physically assessed according to the percent contrast (QH,10), background variability (N10), standardized uptake value (SUV), and recovery coefficient (RC). The results were compared with the guideline recommended range proposed by the Japanese Society of Nuclear Medicine and the Japanese Society of Nuclear Medicine Technology. The PET digital phantom was developed from the digital reference object (DRO) of the NEMA IEC body phantom smoothed using a Gaussian filter with a 10-mm FWHM and defined as the reference image. The difference in the SUV between the PET image and the reference image was evaluated according to the root mean squared error (RMSE).
The FWHMs of the Gaussian, Butterworth, Hamming, Hann, Parzen, and Shepp-Logan filters that satisfied the image quality of the FDG-PET/CT standardization guideline criteria were 8-12 mm, 9-11 mm, 9-13 mm, 10-13 mm, 9-11 mm, and 12- 15 mm, respectively. The FWHMs of the Gaussian, Butterworth, Hamming, Hann, Parzen, and Shepp-Logan filters that provided the smallest RMSE between the PET images and the 3D digital phantom were 7 mm, 8 mm, 8 mm, 8 mm, 7 mm, and 11 mm, respectively.
The suitable FWHM for image quality or SUVmax depends on the type of smoothing filter that is applied.

To validate the reliability of nuclear medicine physicians in diagnosing lymphoma using positron emission tomography/computed tomography using 2-deoxy-2-[18F]fluoro-D-glucose (FDG-PET/CT) and to determine findings that reliably suggest lymphoma.
Seventy patients suspected of having lymphoma using FDG-PET/CT were enrolled in this retrospective study. Two nuclear medicine physicians read all the interpretation reports and graded the degree of suspicion by consensus (3: definitely suspicious, 2: probably suspicious, and 1: possibly suspicious). The following factors were also investigated for each patient: maximum standardized uptake value (SUVmax) of the lesions, serum level of soluble interleukin-2 receptor (sIL-2R), and the presence of splenic FDG uptake higher than that of the liver.
The study group consisted of 34 lymphomas, 18 other malignancies, and 18 benign lesions according to histopathological diagnosis. No patient with a Grade 1 degree of suspicion was diagnosed as lymphoma. SUVmax and the serum level of sIL2-R could not distinguish lymphoma from other diseases. Of the 11 patients who presented with elevated splenic FDG uptake, 10 were diagnosed as having lymphoma.
When the degree of suspicion by nuclear medicine physicians is low, the possibility of lymphoma is also low. On the other hand, elevated splenic FDG uptake may suggest lymphoma.