Daniel Hueng-Yuan Shen

We report a 55-year-old man with metastatic castration-resistant prostate cancer who developed a dramatic “scintigraphic flip” after the second cycle of ¹⁷⁷Lu-PSMA therapy. Post-therapy SPECT and follow-up ¹⁸F-PSMA PET/CT showed increased diffuse marrow uptake with paradoxically reduced salivary-gland and liver activity. Despite improved bone pain, reduced analgesic use, and no clinical or laboratory warning signs, this silent redistribution preceded grade III thrombocytopenia and marked anemia, hospitalization for transfusion and supportive care, and death. This case suggests that interval PSMA PET/CT, particularly in selected high-risk patients, may help identify occult marrow redistribution and support individualized dose adaptation.

This report presents a within-patient comparison of ¹⁸F-rhPSMA-7.3 and ¹⁸F-PSMA-1007 PET/CT in a 71-year-old man with Gleason score 4 + 3 = 7, pT3bN1 metastatic castration-resistant prostate cancer after robot-assisted radical prostatectomy, multiple androgen-deprivation and androgen receptor-directed treatments, and radiotherapy for para-aortic nodal metastases. The scans showed concordant PSMA-avid cervical-to-mediastinal lymphadenopathy and an ill-defined right lower-lobe pulmonary lesion with a recorded SUVmax > 15, despite distinct physiologic biodistributions. Infection or inflammation remained a relevant differential diagnosis, and the patient declined biopsy. Antibiotics did not improve the CT findings. After enrollment in a clinical trial of systemic therapy, the last available pretreatment prostate-specific antigen (PSA) level of 42.4 ng/mL decreased to 3.1 ng/mL, with marked disease regression. The concordant dual-tracer findings, lack of response to antibiotics, and subsequent radiographic and biochemical response to systemic therapy favored nodal and pulmonary metastases from prostate cancer. However, without histopathologic confirmation, the diagnosis remains presumptive, highlighting the need to integrate PET biodistribution, semiquantitative uptake, anatomic imaging, and longitudinal clinical findings.

A 50-year-old woman presented a rapidly proliferative cystic lesion in the left pelvis as displayed by sonography. Exploratory laparoscopy with omental biopsy suggested pseudomyxoma peritonei (PMP). An ¹⁸F-FDG PET/CT revealed scalloping of the liver surface with an associated extrahepatic lesion exhibiting moderate FDG avidity and strand-like FDG uptake within a left-sided septated ovarian cyst. The diagnosis of low-grade appendiceal mucinous neoplasms was proven after cytoreductive surgery. This case provided important imaging features on ¹⁸F-FDG PET/CT that directed the pre-operative diagnosis and the initiation of treatment.

Background/Aim: This study aimed to explore changes in cardiovascular performance among patients with thyroid cancer following thyroidectomy, radioiodine therapy (RAIT) and thyroid-stimulating hormone suppression therapy (TST), with or without treatment with tyrosine kinase inhibitors (TKIs). Patients and Methods: We enrolled 32 patients who underwent thyroidectomy and subsequent RAIT (except for one patient who underwent partial thyroidectomy only) and TST, with or without TKI therapy. We assessed myocardial perfusion using quantitative myocardial perfusion imaging (qMPI), myocardial blood flow (MBF), and coronary flow reserve (CFR) via dynamic single photon-emission computed tomography/computer tomography. We also analyzed data from laboratory tests or heart-related circulation markers, such as N-terminal pro B-type natriuretic peptide (NT-proBNP) to compare patient results, including correlations with different TKIs, RAIT, and TST. Results: qMPI indicated that the TKI-treated group (n=19) exhibited reduced MBF, CFR, and coronary flow capacity compared to the non-TKI-treated group. The right coronary artery (RCA) territory was notably affected by TKI treatment, particularly during the stress phase: RCA-stress blood flow: 2.4±0.6 vs. 1.9±0.7 ml/min/g; RCA-CFR: 2.3±0.8 vs. 2.93±0.9 for TKI-treated vs. non TKI-treated groups, respectively. This effect was more pronounced in the subgroup undergoing sequential anti-vascular endothelial growth factor TKI treatment (e.g. sorafenib and lenvatinib) (n=4) compared to non-TKI-treated controls. Additionally, TKI-treated patients showed a higher mean NT-ProBNP level (203±322.2 pg/ml) than non-TKI-treated patients (39.1±36 pg/ml). Abnormal MBF/CFR was also associated with higher cumulative RAIT dose and lower thyrotropin level. Conclusion: TKI therapy, especially anti-vascular endothelial growth factor TKI, can negatively affect myocardial perfusion and lead to coronary microcirculation dysfunction, reducing MBF/CFR during the stress phase. The link between cumulative RAIT dose, lower thyroid-stimulating hormone level, and abnormal MBF/CFR highlights the need for further research.

Background/Objectives: Tl-201 myocardial perfusion single-photon emission computed tomography (MPS) is a minimally invasive test for patients with suspected coronary artery disease (CAD). While its predictive and prognostic values are well established, diagnostic performance varies. A recent meta-analysis reported that the sensitivity and specificity of MPS range from 48.8 to 100% and 46.7 to 94.7%, respectively, reflecting discordance between CAG. Little is known, however, about the influence of patients’ characteristics and CAD risk factors on the diagnostic performance of MPS. This study aims to evaluate these factors in relation to MPS performance. Methods: We screened 4817 consecutive patients referred to our Nuclear Medicine Department in 2015 for Tl-201 MPS. Patients with clinically suspected ischemic heart disease who underwent CAG within 60 days post-MPS were included in the present analysis. The percentage of agreement/disagreement between the MPS-abnormal/normal and CAG-positive/negative groups was evaluated. Additionally, patient characteristics, CAD risk factors, co-morbidities, and single-photon emission computed tomography (SPECT) image-derived parameters were compared among the patients. Results: Among 635 patients with abnormal MPS, 583 had coronary stenosis. For the 52 without stenosis, causes included non-obstructive CAD (34.6%), prior infarction with scarring (32.7%), and imaging artifacts (32.7%). Significant stenosis was associated with older age, male sex, diabetes, dyslipidemia, CKD, and prior PCI, while hypertension and higher BMI were more common in insignificant CAD. Among 104 patients with normal MPS, 79 had stenosis, mainly in the LAD. Clinical risk factors were more prevalent in patients with any degree of stenosis. Conclusions: In patients with an abnormal MPS, the incorporation of visual interpretation, parameters, and CAD risk factors increases specificity and helps differentiate obstructive from non-obstructive CAD.

We report a case of a 73-year-old man with minimally invasive lung adenocarcinoma, post-resection, evaluated with ¹⁸F-FDG PET/CT for suspected disease progression. Imaging showed increased FDG uptake in the right lower lung mass and systemic lymphadenopathy (mediastinal, supraclavicular, axillary, paraaortic, and iliac regions). The appearance of a stable lymph node and a clinical history of IgG4 lymphadenopathy suggested an inflammatory process, although malignancy in the lung mass and mediastinal nodes could not be excluded. Lobectomy confirmed the presence of lung adenocarcinoma, while radical lymph node dissection identified IgG4-related lymphadenopathy without metastasis. This case underscores the need for considering differential diagnosis of PET-positive lymphadenopathy, especially in patients with comorbid conditions that mimic or coexist with malignancy.

Myxofibrosarcoma is a type of soft tissue sarcoma, predominantly characterized by a high propensity for local recurrence, albeit demonstrating a relatively diminished risk for distant metastasis. Its prevalence is notably higher in elderly patients. Here, we present a case of a 73-year-old woman diagnosed with Myxofibrosarcoma. She was subjected to a whole-body bone scan using ^99mTc-methylene diphosphonate (MDP) to survey potential bony metastasis. It revealed marked MDP accumulation with peripheral soft tissue uptake in the right lateral chest region of this patient. This imaging phenotype could potentially be attributed to the augmented vascularity within the tumor, a finding that was prominently displayed in this particular case.

A 31-year-old man was diagnosed with a COVID-19 infection, presenting with a diffuse headache and an uneven sensation of fullness, despite having no prior systemic diseases. 99mTc-ECD Brain SPECT/CT revealed a marked decrease in blood perfusion in the cerebral cortices, predominantly in the frontal region and involving the olfactory sulcus. In contrast, there was increased perfusion in the occipital lobe and asymmetrical perfusion in the cerebellum. This case highlights changes in regional blood flow perfusion that might affect the functional connectivity of the pain matrix, leading to the onset of headaches and associated underlying mechanisms.

Mass vaccination against coronavirus disease 2019 (COVID-19) is a global health strategy to control the COVID-19 pandemic. With the increasing number of vaccinations, COVID-19 vaccine-associated lymphadenopathy (C19-VAL) has been frequently reported. Current findings emphasize the characteristics of C19-VAL. The mechanism of C19-VAL is complicated to explore. Accumulated reports separately show that C19-VAL incidence is associated with receiver age and gender, reactive change within lymph nodes (LN), etc. We constructed a systematic review to evaluate the associated elements of C19-VAL and provide the mechanism of C19-VAL. Articles were searched from PubMed, Web of Science and EMBASE by using the processing of PRISMA. The search terms included combinations of the COVID-19 vaccine, COVID-19 vaccination and lymphadenopathy. Finally, sixty-two articles have been included in this study. Our results show that days post-vaccination and B cell germinal center response are negatively correlated with C19-VAL incidence. The reactive change within LN is highly related to C19-VAL development. The study results suggested that strong vaccine immune response may contribute to the C19-VAL development and perhaps through the B cell germinal center response post vaccination. From the perspective of imaging interpretation, it is important to carefully distinguish reactive lymph nodes from metastatic lymph node enlargement through medical history collection or evaluation, especially in patients with underlying malignancy.

Gamma-ray irradiation is an effective and clean method of sterilization by inactivating microorganisms. It can also be applied to induce anti-oxidants for future application. In this study, the mung bean (Vigna radiata) was exposed to gamma-ray irradiation under the dose of 0, 5 or 10 kGy. With increasing irradiation doses, the concentrations of malondiadehyde decreased while the levels of total flavonoids and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity increased. It has been shown that consuming flavonoids can provide protective effects. In addition, proteomic analysis identified several proteins having anti-oxidant activities in the 5 kGy irradiated group. These proteins are Apocytochrome f, Systemin receptor SR 160, DELLA protein DWARF8, DEAD-box ATP-dependent RNA helicase 9, ζ-carotene desaturase (ZDS), and Floral homeotic protein AGAMOUS. Our findings indicate that plants contain a variety of phytochemicals and antioxidant proteins which may effectively prevent oxidative stress caused by irradiated peroxidation.