Background 99mTc–prostate-specific membrane antigen (PSMA) SPECT/CT is less expensive and readily available modality compared with 68Ga-PSMA PET/CT for imaging prostate cancer (PC). The aim of this study is to compare the value of these 2 modalities in patients confirmed or suspicious to have metastatic prostate cancer. Patients and Methods Twenty-two patients with the mean age of 66.6 ± 10.1 years were studied using 99mTc-PSMA SPECT/CT and 68Ga-PSMA PET/CT, with less than 7 days interval between the 2 imaging procedures. Whole-body PET/CT was done 60 minutes after IV injection of 185 MBq (5 mCi) of 68Ga-PSMA. 99mTc-PSMA SPECT/CT was performed 3 hours after IV injection of 555 to 740 MBq (15–20 mCi) of 99mTc-PSMA. The images of each modality were interpreted independently, and the results were compared according to patient-based as well as region-based analyses. Results In patient-based evaluation, both 99mTc-PSMA SPECT/CT and 68Ga-PSMA PET/CT scans were positive in 95.45% (21/22). In region-based evaluation, 68Ga-PSMA PET/CT detected 53 regions (median of 2 regions per patient; range, 0–5), whereas 43 (median of 2 regions per patient; range, 0–5) were detected by 99mTc-PSMA SPECT/CT. Most of these differences could be explained by lower detection rate of 99mTc-PSMA SPECT/CT in prostate bed (n = 6). PET/CT detected more involved regions than SPECT/CT (P = 0.007), whereas similar frequency of extraprostatic lesions were diagnosed in both modalities (P = 0.102). Significant correlation was also demonstrated between serum prostate-specific antigen level and imaging parameters of disease extension detected by 2 modalities. Conclusions 99mTc-PSMA SPECT/CT could be a potential substitute for 68Ga-PSMA PET/CT in high-risk patients, except when evaluation of prostate bed is of major concern.

NLDO may be considered as a side effect of I-131 therapy, especially with a cumulative dose of 11.1 GBq or more.

Purpose This work was set out to investigate the feasibility of dose reduction in SPECT myocardial perfusion imaging (MPI) without sacrificing diagnostic accuracy. A deep learning approach was proposed to synthesize full-dose images from the corresponding low-dose images at different dose reduction levels in the projection space. Methods Clinical SPECT-MPI images of 345 patients acquired on a dedicated cardiac SPECT camera in list-mode format were retrospectively employed to predict standard-dose from low-dose images at half-, quarter-, and one-eighth-dose levels. To simulate realistic low-dose projections, 50%, 25%, and 12.5% of the events were randomly selected from the list-mode data through applying binomial subsampling. A generative adversarial network was implemented to predict non-gated standard-dose SPECT images in the projection space at the different dose reduction levels. Well-established metrics, including peak signal-to-noise ratio (PSNR), root mean square error (RMSE), and structural similarity index metrics (SSIM) in addition to Pearson correlation coefficient analysis and clinical parameters derived from Cedars-Sinai software were used to quantitatively assess the predicted standard-dose images. For clinical evaluation, the quality of the predicted standard-dose images was evaluated by a nuclear medicine specialist using a seven-point (− 3 to + 3) grading scheme. Results The highest PSNR (42.49 ± 2.37) and SSIM (0.99 ± 0.01) and the lowest RMSE (1.99 ± 0.63) were achieved at a half-dose level. Pearson correlation coefficients were 0.997 ± 0.001, 0.994 ± 0.003, and 0.987 ± 0.004 for the predicted standard-dose images at half-, quarter-, and one-eighth-dose levels, respectively. Using the standard-dose images as reference, the Bland–Altman plots sketched for the Cedars-Sinai selected parameters exhibited remarkably less bias and variance in the predicted standard-dose images compared with the low-dose images at all reduced dose levels. Overall, considering the clinical assessment performed by a nuclear medicine specialist, 100%, 80%, and 11% of the predicted standard-dose images were clinically acceptable at half-, quarter-, and one-eighth-dose levels, respectively. Conclusion The noise was effectively suppressed by the proposed network, and the predicted standard-dose images were comparable to reference standard-dose images at half- and quarter-dose levels. However, recovery of the underlying signals/information in low-dose images beyond a quarter of the standard dose would not be feasible (due to very poor signal-to-noise ratio) which will adversely affect the clinical interpretation of the resulting images.

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Background: The assessment of body composition during the course of treatment of hemodialysis patients is crucial for optimal treatment. We intended to assess the diagnostic performance of bioelectrical impedance analysis (BIA), which could be used at the bedside in dialysis wards, and compare it with the results of dual-energy X-ray absorptiometry (DEXA). Methods: In a cross-sectional study, 43 patients with end-stage renal disease (ESRD) after hemodialysis sessions underwent direct segmental multi-frequency BIA. Volume status and body composition indices with eight electrodes connected to four limbs were measured at 1, 5, 50, 250, 500, and 1000 kHz frequencies. Then, the patients were sent to the nuclear ward for the corresponding assessments by DEXA. The results of the two methods were compared by a paired t-test and the correlations were assessed using general linear models and regression analyses. For the assessment of agreements, Bald-Altman plots were used. Results: The whole body values for bone, fat, and lean body mass were different between BIA (3.4, 22, and 44.5 kg, respectively) and DEXA (1.5, 28.5, and 40.4 kg, respectively). However, the results were strongly linearly correlated even after adjustment for age and sex (r = 0.67, P = 0.001 for bone mass; r = 0.93, P = 0.001 for fat mass; and r = 0.96, P = 0.001 for lean body mass). The same strong correlation was found for the segmental values. Conclusions: The results of BIA and DEXA are correlated strongly and are interchangeable. As the BIA is more easily available and less expensive, the routine use of BIA at hemodialysis departments is reasonable.

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Nuclear medicine is defined as the diagnosis and the treatment of disease using radiolabeled compounds known as radiopharmaceuticals. Single-photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/computer tomography (PET/CT) based radiopharmaceuticals have proven reliable in diagnostic imaging in nuclear medicine and cancer treatment. One of the most critical cancers that also relies on an early diagnosis is gynecological cancer. Given that approximately 25% of all cancers in developing countries are a subset of gynecological cancer, investigating this cancer subtype is of significant clinical worth, particularly in light of its high rate of mortality. With accurate identification of high grade distant abdominal endometrial cancer as well as extra abdominal metastases, 18F-Fluorodeoxyglucose ([18F]FDG) PET/CT imaging is considered a valuable step forward in the investigation of gynecological cancer. Considering these factors, [18F]FDG PET/CT imaging can assist in making management of patient therapy more feasible. In this literature review, we will provide a short overview of the role of nuclear medicine in the diagnosis of obstetric and gynecological cancers.