Targeted alpha therapy (TAT) is an active area of drug development as a highly specific and highly potent therapeutic modality that can be applied to many types of late-stage cancers. In order to properly evaluate its safety and efficacy, understanding biokinetics of alpha-emitting radiopharmaceuticals is essential. Quantitative imaging of alpha-emitting radiopharmaceuticals is often possible via imaging of gammas and positrons produced during complex decay chains of these radionuclides. Analysis of the complex decay chains for alpha-emitting radionuclides (Tb-149, At-211, Bi-212 (decayed from Pb-212), Bi-213, Ra-223, Ac- 225, and Th-227) with relevance to imageable signals is attempted in this mini-review article. Gamma camera imaging, single-photon emission computed tomography, positron emission tomography, bremsstrahlung radiation imaging, Cerenkov luminescence imaging, and Compton cameras are briefly discussed as modalities for imaging alpha-emitting radiopharmaceuticals.
Electrons ; Luminescence ; Positron-Emission Tomography ; Radioisotopes ; Radionuclide Imaging ; Radiopharmaceuticals ; Tomography, Emission-Computed ; Tomography, Emission-Computed, Single-Photon

PET/CT fused image with anatomical and functional information have improved medical diagnosis and interpretation. This fusion has resulted in more precise localization and characterization of sites of radio-tracer uptake. However, a motion during whole-body imaging has been recognized as a source of image quality degradation and reduced the quantitative accuracy of PET/CT study. The respiratory motion problem is more challenging in combined PET/CT imaging. In combined PET/CT, CT is used to localize tumors and to correct for attenuation in the PET images. An accurate spatial registration of PET and CT image sets is a prerequisite for accurate diagnosis and SUV measurement. Correcting for the spatial mismatch caused by motion represents a particular challenge for the requisite registration accuracy as a result of differences in PET/CT image. This paper provides a brief summary of the materials and methods involved in multiple investigations of the correction for respiratory motion in PET/CT imaging, with the goal of improving image quality and quantitative accuracy.
Positron-Emission Tomography and Computed Tomography

No abstract available.
Positron-Emission Tomography and Computed Tomography*

No abstract available.
Positron-Emission Tomography and Computed Tomography*

Positron Emission tomography Response Criteria In Solid Tumors (PERCIST) version 1.0 was introduced in 2009 for objective assessment of tumor metabolic response using ¹⁸F-FDG PET/CT. Practical PERCIST: A Simplified Guide to PET Response Criteria in Solid Tumors 1.0 was published in 2016 to review and clarify some of the issues with the PERCIST. In this article, we reflect on the benefits and challenges of implementing PERCIST, and speculate on topics that could be discussed in PERCIST 1.1 in the future.
Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography

positron emission tomography/computed tomography (PET/CT) in detecting hyperfunctioning parathyroid tissue (HPT) in patients with elevated parathyroid hormone levels with negative or inconclusive conventional imaging results and to compare the findings with those obtained using technetium-99m sestamibi (MIBI) scintigraphy and neck ultrasonography (US).MATERIALS AND METHODS: Images of 105 patients with hyperparathyroidism who underwent FCH PET/CT, dual-phase MIBI parathyroid scintigraphy (median interval: 42 days), and neck US were retrospectively analyzed. The gold standard was histopathological findings for 81 patients who underwent parathyroidectomy and clinical follow-up findings in the remaining 24 patients. Sensitivities, positive predictive values (PPVs), and accuracies were calculated for all imaging modalities.RESULTS: Among the 81 patients who underwent parathyroidectomy, either parathyroid adenoma (n = 64), hyperplasia (n = 9), neoplasia (n = 4), or both parathyroid adenoma and hyperplasia (n = 1) were detected, except 3 patients who did not show HPT. Of the 24 (23%) patients who were followed-up without operation, 22 (92%) showed persistent hyperparathyroidism. FCH PET/CT showed significantly higher sensitivity than MIBI scintigraphy and US in detection of HPT (p < 0.01). Sensitivity, PPV, and accuracy of FCH PET/CT were 94.1% (95/101), 97.9% (95/97), and 92.4% (97/105), respectively. The corresponding values for MIBI scintigraphy and US were 45.1% (46/102), 97.9% (46/47), and 45.7% (48/105) and 44.1% (45/102), 93.8% (45/48), and 42.9% (45/105), respectively. Among the 35 patients showing negative MIBI scintigraphy and neck US findings, 30 (86%) showed positive results on FCH PET/CT. FCH PET/CT could demonstrate ectopic locations of HPT in 11 patients whereas MIBI and US showed positive findings in only 6 and 3 patients, respectively.CONCLUSION: FCH PET/CT is an effective imaging modality for detection of HPT with the highest sensitivity among the available imaging techniques. Therefore, FCH PET/CT can be recommended especially for patients who show negative or inconclusive results on conventional imaging.]]>
Electrons ; Follow-Up Studies ; Humans ; Hyperparathyroidism ; Hyperplasia ; Neck ; Parathyroid Hormone ; Parathyroid Neoplasms ; Parathyroidectomy ; Positron-Emission Tomography ; Positron-Emission Tomography and Computed Tomography ; Radionuclide Imaging ; Retrospective Studies ; Ultrasonography

Background: Non-specific focal uptake in the skeleton is a diagnostic pitfall on 18F-PSMA-1007 PET/CT, but adjunctive measures to aid interpretation of these lesions are currently lacking. We present two cases where dual time point imaging provided additional information. Case Presentation: The first patient had a PI-RADS 3 lesion on MRI. No PSMA-avid abnormality was seen on PET, save for focal uptake in the right pubis with no anatomic correlate. Additional imaging showed a decrease in lesion SUV, and this was interpreted as benign. Another patient, diagnosed with prostate cancer, had multiple PSMA-avid pelvic foci. Two suspiciously malignant bone lesions had increasing SUV trend after dual time point imaging despite only faint sclerosis on CT. In contrast, one faint PSMA-avid lesion with no anatomic abnormality was read as benign after a decrease in SUV. A decrease in lesion SUV may point to a benign etiology, while an increase would heighten suspicion for malignancy. One possible molecular explanation is that a true PSMA-overexpressing lesion would bind to the tracer for a longer period than a false positive. Conclusion Dual time point imaging provides additional information that may be useful in the interpretation of non-specificskeletal lesions with increased 18F-PSMA-1007 uptake.
PSMA-1007 ; Positron Emission Tomography Computed Tomography

No abstract available.
Nephritis* ; Positron-Emission Tomography and Computed Tomography* ; Succimer*

In this paper are presented and recommended the researches of the left ventricle model and optimization arithmetic based on myocardial radionuclide tomographic images (SPECT and PET). We adopted the hemispheric-cylindrical myocardial model which was largely used in quantitative analysis of myocardium. Then we adopted the radionuclide maximum counts method in LV myocardium and used the Powell optimization arithmetic to fit the myocardial model. Comparing the result from the adopted method against that of the doctors' diagnosis, we found the rate of high relevancy being 83.2%.
Algorithms ; Gated Blood-Pool Imaging ; Heart Ventricles ; diagnostic imaging ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Models, Cardiovascular ; Myocardium ; Positron-Emission Tomography ; methods ; Tomography, Emission-Computed, Single-Photon ; methods

Testicular torsion is a common differential diagnosis of acute scrotal pain along with acute epididymo-orchitis, which may lead to testicular non-viability. Doppler ultrasound and testicular scintigraphy are two routinely used modalities for the assessment of testicular viability. However, in some cases, these investigations may prove inadequate in differentiating between the two entities with widely differing management. Here, we present a case of a 52-year-old male with questionable viability of testis, who was investigated initially using testicular scintigraphy and was further subjected to a regional 18F-FDG PET/CT scan, in view of inconclusive findings with the conventional modalities.
Diagnosis, Differential ; Fluorodeoxyglucose F18 ; Humans ; Male ; Middle Aged ; Positron-Emission Tomography and Computed Tomography ; Radionuclide Imaging ; Spermatic Cord Torsion ; Testis ; Ultrasonography