NUCLEAR MEDICINE REVIEW最新文献

Background: This study aims to evaluate the feasibility of generating pseudo-normal single photon emission computed tomography (SPECT) data from potentially abnormal images. These pseudo-normal images are primarily intended for use in an on-the-fly data harmonization technique.

Material and methods: The methodology was tested on brain SPECT with [123I]Ioflupane. The proposed model for generating a pseudo-normal image was based on a variational autoencoder (VAE) designed to process 2D sinograms of the brain [123I]-FP-CIT SPECT, potentially exhibiting abnormal uptake. The model aimed to predict SPECT sinograms with corresponding normal uptake. Training, validation, and testing datasets were created by SPECT simulator from 45 brain masks segmented from real patient's magnetic resonance (MR) scans, using various uptake levels. The training and validation datasets each comprised 612 and 360 samples, respectively, drawn from 36 brain masks. The testing dataset contained 153 samples based on 9 brain masks. VAE performance was evaluated through brain dimensions, Dice similarity coefficient (DSC) and specific binding ratio.

Results: Mean DSC was 80% for left basal ganglia and 84% for right basal ganglia. The proposed VAE demonstrated excellent consistency in predicting basal ganglia shape, with a coefficient of variation of DSC being less than 1.1%.

Conclusions: The study demonstrates that VAE can effectively estimate an individualized pseudo-normal distribution of the radiotracer [123I]-FP-CIT SPECT from abnormal SPECT images. The main limitations of this preliminary research are the limited availability of real brain MR data, used as input for the SPECT data simulator, and the simplified simulation setup employed to create the synthetic dataset.

Background: Cardiac amyloidosis (CA) is a progressive disease in which amyloid fibrils infiltrate the heart muscle. This study aimed to identify features from cardiac biomarkers, electrocardiography (ECG), and echocardiography that may distinguish between transthyretin amyloidosis (ATTR) scintigraphy-positive and negative patients.

Material and methods: Seventy-eight consecutive patients, median age 69 years (range 34-81), with suspected CA, negative serum free light chains, and negative serum and urine protein electrophoresis with immunofixation, referred to cardiac scintigraphy between 2021 and 2024, were retrospectively enrolled. Cardiac uptake was assessed by Perugini grades. Troponin T, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and various ECG and echocardiographic features were compared between ATTR scintigraphy-positive and negative participants using the t-test, Mann-Whitney U-test, and χ2-test as appropriate. Multivariable stepwise logistic regression created the prediction model for ATTR-positive scintigraphy. The significance level was 0.05.

Results: Scintigraphy was ATTR-positive in 24 participants (30.77%). The variables significantly connected with ATTR-positive testing were atrial fibrillation (p = 0.010), first- or second-degree atrioventricular block (p = 0.041), left ventricle (LV) end-diastolic dimension (p = 0.018), LV global longitudinal strain (GLS) (p = 0.040), a restrictive transmitral inflow pattern (p = 0.025), LV posterior wall thickness (p < 0.001), interventricular septum (IVS) thickness (p < 0.001), QRS voltages (p < 0.001), the pseudo- infarct pattern (p < 0.001), and relative apical sparing of the GLS ratio (p < 0.001). The latter four were incorporated into the prediction model for ATTR-positive scintigraphy.

Conclusions: ECG and echocardiography remain the essential diagnostic procedures that raise the suspicion of CA and trigger further diagnostics. Low QRS voltages, the pseudo-infarct pattern, IVS thickness, and relative apical sparing of the GLS ratio are sensitive predictors of ATTR-positive scintigraphy findings.

Background: Bone metastases are complications of many cancers, including colon cancer. Whole body bone scan is commonly used to detect bone metastases in these patients. Bone scan findings are sensitive for detecting metastases but with less experience and especially without the use of single photon emission computed tomography/computed tomography (SPECT/CT) images, they are less specific. This means that while bone scans are effective at identifying areas of abnormal bone activity, they may not always distinguish between bone metastases and other conditions, such as fractures, infections, or benign bone diseases such as a rare condition like osteopetrosis, leading to potential false positives. This 52-year-old male patient was referred for a whole-body bone scan for evaluation of bone metastasis. At first glance, the scan pattern with multiple foci of increased radiotracer uptake seemed to indicate bone metastases due to the patient's colon cancer. However, upon closer inspection of the bone scan and careful attention to details such as bone deformities and cortical thickening, along with obtaining a more detailed patient history and reviewing other radiological records, the diagnosis of osteopetrosis was made.

Conclusions: This case demonstrates the importance of carefully interpreting bone scan findings when diagnosing metastasis. It highlights that other benign diseases, including rare conditions such as osteopetrosis, can mimic the appearance of bone metastases on scans. Therefore, it is crucial to pay close attention to any abnormal patterns, like cortical thickening and bone deformity, and to thoroughly review the patient's medical history and other relevant clinical data and imaging findings. This comprehensive approach helps avoid misdiagnosis and ensures accurate interpretation of the scan results.

Background: Neuroendocrine tumours (NETs) are a group of cancers that can produce hormones and other metabolically active compounds. The majority of NETs have specific tissue characteristics, such as the expression of somatostatin receptors (SSTR). Metabolic testing with [99mTc]Tc-EDDA/HYNIC-Tyr3-octreotide ([99mTc]Tc-EDDA/HYNIC-TOC) can be used in patients with NETs to visualize the presence of receptors in different locations of pathological lesions, including the skeletal system. The study aimed to calculate the body weight maximum standardized uptake value (SUVbwmax) of pathological bone lesions and healthy bone tissues, estimate the size of lesions, and identify a relationship between the SUVbwmax of the bone tissues, age and body mass of the study participants.

Material and methods: The somatostatin receptor scintigraphies (SRS) with [99mTc]Tc-EDDA/HYNIC-TOC were carried out at the Department of Nuclear Medicine, University Clinical Hospital No. 1, Pomeranian Medical University (PMU) in Szczecin from 2019 to 2022. Whole body and single photon emission computed tomography/computed tomography (SPECT/CT) scans were performed four hours after the injection of 700-800 MBq of [99mTc]Tc-EDDA/HYNIC-TOC in 344 patients with neuroendocrine tumours of various primary lesion locations. In 19 patients, who showed foci of increased radiopharmaceutical accumulation in bone location, the SUVbwmax was measured. The SUVbwmax of pathological bone lesions and healthy tissues were determined on SPECT/CT cross-sectional images using Xeleris 4 software.

Results: The total number of foci with increased SSTR expression in bone regions seen on scintigraphic images was 89. Among them, 32 bone lesions were visible on the corresponding CT scans. The mean SUVbwmax of these lesions was 31.39 [standard deviation (SD) 34.31]. For the other 57 lesions that were not visible on corresponding CT scans, the mean SUVbwmax was 19.12 (SD 24.24). The smallest bone lesion detected on the scintigram and visible on the corresponding CT location was 5 mm × 5 mm, measured in cross-section, and was located in the Th8 vertebral body; the largest, measuring 20 mm × 22 mm, was detected in the L3 vertebral body. The SUVbwmax of these lesions was 24.70 and 142.40, respectively.

Conclusions: Bone lesions seen on SPECT/CT in [99mTc]Tc-EDDA/HYNIC-TOC scintigraphy can be quantitatively analysed using the SUV index. Even a very small pathological bone lesion can be detected on [99mTc]Tc-EDDA/HYNIC-TOC scintigraphy. It was shown that in cases where bone lesions were visible on CT scans, the SUVbwmax of bone tumour lesions was higher than when lesions were not visible on CT. Body mass does not affect the SUVbwmax of bone lesions. SUVbwmax of healthy bone tissue decreased with age.

Muir-Torre syndrome (MTS) is a rare genetic disorder, considered a subtype of Lynch syndrome, that causes sebaceous cutaneous tumors and increases the risk of internal visceral tumors. We present a case of a 63-year-old male with a history of MTS with sebaceous tumors, colorectal, and urothelial cancers who underwent fluorine-18-deoxyglucose positron emission tomography/ computed tomography [18F]FDG PET/CT to follow-up on multiple [18F]FDG avid skin lesions and right pelvic lymph nodes. Although few reports are available detailing the utility of [18F]FDG PET/CT in this rare disease, this modality appears useful, and superior, to computed tomography in the diagnosis and follow-up of MTS.

Background: As in disease recurrence, providing clinicians with the exact extent of the disease at the time of initial diagnosis is key in the management and individual treatment of prostate cancer (PC) patients. Intending to examine the usefulness of gallium- 68 PSMA-11 positron emission tomography/computed tomography ([68Ga]Ga-PSMA-11 PET/CT) and to determine if there is a correlation between prostate-specific antigen (PSA) serum values, WHO/ISUP (World Health Organization/International Society of Urological Pathology's) grade group of the tumor and SUVmax (maximized standardized uptake value) values we retrospectively analyzed PET/CT studies performed for initial staging of the disease.

Patients and methods: We retrospectively evaluated 34 studies of patients who underwent [68Ga]Ga-PSMA-11 PET/CT as part of the initial staging of prostate cancer. All patients had prostate cancer confirmed by histological assessment after biopsy and had Gleason score and PSA serum values obtained. The mean PSA value was 33.8 ± 40.9 nmol/L (range 2.2-232).

Results: Nineteen patients had extended disease (55.9%). The mean SUVmax in prostate lesions was 19.5 ± 12.6. The mean value of SUVmax of PET studies in the high-risk group was significantly higher than those of low risk (23.5 ± 13.2 and 10.6 ± 5.4, p < 0.05). A positive correlation was observed between the ISUP group and SUVmax value of prostate lesions (Pearson's r = 0.557, p < 0.01). A positive correlation was also found in the comparison between PSA values and SUVmax (Pearson's r = 0.34, p < 0.05).

Conclusions: In our study, [68Ga]Ga-PSMA-11 PET/CT scans detected the extended disease in more than half of the patients. Locating disease beyond the prostate gland allowed better informed clinical decisions and modified treatment. A positive correlation was found between intraprostatic SUVmax values and the ISUP group of prostate cancer. High-risk patients had SUVmax values that were significantly higher than those of low-risk patients. The correlation between the Gleason score and SUVmax value can be explained by the increased intensity of PSMA expression as the tumor grade increases.

Background: Nuclear medicine uses radionuclides in medicine for diagnosis, staging, therapy, and monitoring the response to therapy. The application of radiopharmaceutical therapy for the treatment of certain diseases is well-established, and the field is expanding. Internal dosimetry is multifaceted and includes different workflows, as well as various calculations based on patient- specific dosimetry.

Aim: The objective of this study was to introduce the technical issues which might occur during iodine-131 (¹³¹I) dosimetry performed in nuclear medicine departments.

Material and methods: Retrospective analysis was performed on a group of 44 patients with papillary thyroid cancer who between May 2021 and October 2021 underwent a 131I treatment: 80-100 mCi (2200-3700 MBq, based on the previous medical history and stage of the disease). Patients underwent a series of ¹³¹I therapy scans using gamma camera Discovery NM 670 CT. Whole body scan (WBS) was performed 2, 4, 24 and 48 hours after ¹³¹I administration. Additionally, after 24 hours of single photon emission computed tomography/ computed tomography, two fields of view (SPECT/CT 2-FOV) were performed from the mid-head to the bladder.

Results: During the dosimetry procedure, several issues arise. Firstly, after receiving therapeutic doses of ¹³¹I, patients should remain in their rooms until the appropriate activity is achieved before being transported to the diagnostic room. Secondly, the walls between examination rooms meet the requirements for accurate diagnosis but not for therapy, leading to the occurrence of artefacts in patients examined behind the wall, potentially influencing the examination results. Thirdly, personnel in the control room also experience additional exposure (10 times greater than in the case of standard diagnostic procedure).

Conclusions: The dosimetry in patients in whom therapeutic procedures are performed with the use of isotopes is mandatory according to Polish and European law, technical issues which occur during the dosimetry procedures might influence the organization of the work in departments.

Background: Therapeutic radiopharmaceuticals [¹⁷⁷Lu]Lu-DOTA-TATE and [⁹⁰Y]Y-DOTA-TATE are used in peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors. One of the factors determining the efficacy of such therapy is administering the radiopharmaceutical dose to the patients in a way consistent with treatment planning. This paper evaluates the loss of [¹⁷⁷Lu]Lu-DOTA-TATE and [⁹⁰Y]Y-DOTA-TATE and their mixed doses during the administration to the patient either by direct infusion or by gravity method.

Material and methods: The loss of [¹⁷⁷Lu]Lu-DOTA-TATE and [⁹⁰Y]Y-DOTA-TATE, was assessed in tests simulating the administration procedures and during infusion to the patients performed at four clinical centres. One clinical centre used a direct infusion, and three others used a gravity method to administer radiopharmaceuticals to the patient.

Results: In the direct infusion the highest radioactivity loss was 3.88% ± 0.49% (n = 3) and 3.76% ± 0.83% (n = 3) for [¹⁷⁷Lu] Lu-DOTA-TATE infusion with radioactivity of 3.71 GBq ± 0.08 GBq (n = 3) and 1.06 GBq ± 0.08 GBq (n = 3), respectively, and 4.04% ± 0.40% (n = 5) for infusion of [⁹⁰Y]Y-DOTA-TATE dose of 1.98 GBq ± 0.05 GBq (n = 5). In the gravity method administration of [¹⁷⁷Lu]Lu-DOTA-TATE generated losses of up to 1.31% ± 0.46% (n = 16) for a dose of 7.45 GBq ± 0.06 GBq (n = 16) and 2.93% ± 1.64% (n = 8) for a dose of 3.78 GBq ± 0.05 GBq (n = 8). However, the infusion of the lowest doses of 0.95 GBq ± 0.01 GBq (n = 4) [¹⁷⁷Lu]Lu-DOTA-TATE and 1.96 GBq ± 0.03 GBq (n = 8) [⁹⁰Y]Y-DOTA-TATE resulted in higher loss of radiopharmaceuticals up to 6.00% ± 0.97% (n = 4) and 4.00% ± 1.57% (n = 8), respectively.

Conclusions: Both investigated methods of radiopharmaceutical administration are associated with the loss of the radioactivity of radiopharmaceutical.

A 75-year-old man underwent a positron emission tomography/computed tomography (PET/CT) scan with fluorine-18-prostate specific membrane antigen ([¹⁸F]F-PSMA-1007) for initial staging of prostate adenocarcinoma. The scan showed lung infiltrates predominantly in both lower lobes with moderate uptake, in addition to a bilateral pulmonary hilar lymph node uptake. CT images revealed ground-glass opacities and a reticular pattern, suggesting COVID-19 pneumonia, which was confirmed by reverse transcription polymerase chain reaction (RT-PCR). Similar incidental findings have been reported in patients undergoing PET/CT scans with other radiotracers. In this case, the probable lung angiogenesis linked to COVID-19 infection can be potencially demonstrated by [¹⁸F]F-PSMA-1007, which helps ensure timely diagnosis and appropriate care for cancer patients.

The aim of the report is to present the current state of equipment, radiopharmacy, dosimetry, and selected clinical applications, together with proposed new solutions and expected directions of development of classic nuclear medicine and positron emission tomography (PET). The statement presents the individual points of view of the members of the Commission for Nuclear Medicine of the Committee of Medical Physics, Radiobiology and Diagnostic Imaging of the Polish Academy of Sciences in the 2020-2023 term.