World Journal of Nuclear Medicine最新文献

A toddler was diagnosed with extraosseous Ewing's sarcoma, primary large epidural paraspinal soft tissue in the lumbar region encasing the cord and neural foramen from D12-L1 to L4-L5. After eight cycles of induction chemotherapy with vincristine, doxorubicin, and cyclophosphamide alternating with etoposide and ifosfamide, ¹⁸ F-FDG positron emission tomography/computed tomography ( ¹⁸ F-FDG-PET/CT) scan confirmed no active disease. Later external beam radiotherapy (EBRT) at D10-L5 was completed. At 3 months follow-up, ¹⁸ F-FDG-PET/CT reconfirmed no residual/active disease; however, a new incidental finding of diffuse benign bilateral diaphragmatic ¹⁸ F-FDG uptake was noted in the clinically asymptomatic patient, which remained unexplained.

Introduction  Gallbladder cancer (GBC) is one of the most common and aggressive malignancies of the Indo-Gangetic plains. Despite its widespread use in GBC cases, the role of 18-flurodeoxyglucose positron emission tomography-computed tomography ( ¹⁸ FDG PET-CT) in the management of this disease is not well defined. In our study, we present the practice trends of the utilization of this investigative modality in our hospital and its benefits in aiding diagnosis, staging, and surveillance for recurrence. Materials and Methods  All cases of suspected and biopsy-proven GBCs who underwent PET-CT at our institute between 2016 and 2019 were retrospectively evaluated for the indication of PET-CT testing and its impact on the management of the case. The indications were classified into three categories: (i) staging and metastatic workup, (ii) response assessment post-chemotherapy, and (iii) post-therapy surveillance of patients. Results  A total of 79 PET-CT scans were carried out during the study period. PET-CT was used for less than one-third of the total patients of GBC presenting at our center. Initial staging and workup (49%) was the most common indication followed by surveillance (28%) and response assessment (23%). PET-CT had a substantially better sensitivity in detecting distant metastases compared to conventional imaging in both initial workup and during follow-up. PET-CT provided additional information in 42% scans that led to change in the management of the patient. As a response assessment tool PET-CT aided not only in evaluating efficacy of therapy but also for documenting progressive disease for patients on therapy. Conclusion  PET-CT is a valuable tool to not only rule out metastatic disease while selecting patients for surgery but also for post-therapy surveillance for recurrence in patients of GBC. Larger prospective studies may help in finally elucidating the exact role of PET-CT in this disease.

Sarcoidosis is frequently associated with various hematological and solid tumors; it can be discovered by chance during tumor evaluations. Sarcoidosis can occur before some cancers, coexist with others, or be diagnosed 1 to 2 years later. Sarcoid reaction affecting hilar and mediastinal lymph nodes can pose a diagnostic challenge in patients with histopathological confirmation of Hodgkin lymphoma who are being evaluated using fluorodeoxyglucose-positron emission tomography computed tomography (FDG-PET/CT) scan because it cannot be easily distinguished from lymphoma infiltration. The presence of an increase or persistence of a prominent activity on a follow-up FDG-PET/CT scan after chemotherapy treatment for lymphoma that is associated with a complete metabolic response in the site of the primarily diagnosed lymphomatous disease is highly suggestive of concurrent sarcoidosis and necessitates careful assessment to avoid unnecessary therapy.

Differentiated thyroid cancer (DTC) is the most common endocrine cancer and its outcome is usually favorable. Its basic treatment is well codified, but its monitoring is much less. The value of thyroglobulin (Tg) is one of the main elements for monitoring DTC, while the use of iodine scintigraphy is becoming less recommended. In this case report, we discuss a clinical situation where a patient presented differentiated thyroid metastatic lesions confirmed by biopsy, uptaking radioactive iodine, with undetectable levels of Tg (in the absence of autoantibodies). We discuss the various hypotheses explaining this clinical situation, the potential advantages of performing periodic iodine scintigraphy in some intermediate and high-risk patients and report the documented clinical benefit of radioiodine therapy.

Introduction  The quality control (QC) procedures for positron emission tomography (PET) scanners are covered by National Electrical Manufacturers Association and International Electrotechnical Commission. QC must be carried out at regular intervals according to the specifications of the scanner manufacturer. Daily and weekly QC plays a valuable role in monitoring positron emission tomography (PET) scanner performance changes. This study shares operational and performance experience of QC procedures that do not require a radioactive Ge-68 source to perform daily QC and experience with fluorodeoxyglucose F18 ( ¹⁸ F-FDG) as a substitute for germanium-68/sodium-22 (Ge-68/Na-22) source for weekly QC. Method  This study was performed on an uMI550 digital positron emission tomography-computed tomography (PET-CT) scanner. In this scanner daily QC checks system temperature and humidity, system count rate, data link status, and voltage. QC was performed at the console control, the position of the scanner table was in the home position pulled out from the gantry, and the room was closed during the quick QC. Weekly full QC check items include look-up table drift, energy drift, time-of-flight status, C-map status, temperature and humidity, and voltage. Weekly full QC was performed with a ¹⁸ F-FDG source in a rod phantom source. Results  Over 200 daily QC tests without a radioactive source Ge-68 phantom and 50 full weekly QC tests using a ¹⁸ F-FDG rod phantom were performed with this scanner according to the manufacturer's instructions and a test report was generated. No daily QC errors or warnings were observed during this period. Conclusion  The new approach for the daily PET QC does not expose operators to radiation. This translates into commercial and operational merits with consistent performance and results. Implications for Practice  Reduction in radiation exposure to operating staff during QC procedure in PET-CT scanner.