Abstract Background 99m Tc-macroaggregated albumin ( 99m Tc-MAA) scintigraphy is utilized in treatment planning for Yttrium-90 ( 90 Y) Selective Internal Radiation Therapy (SIRT) of liver tumors to evaluate hepatopulmonary shunting by calculating the lung shunt fraction (LSF). The purpose of this study was to evaluate if LSF calculation using SPECT/CT instead of planar gamma camera imaging is more accurate and if this can potentially lead to more effective treatment planning of hepatic lesions while avoiding excessive pulmonary irradiation. Results LSF calculation was obtained using two different methodologies in 85 cases from consecutive patients intended to receive 90 Y SIRT. The first method was based on planar gamma camera imaging in the anterior and posterior views with geometric mean calculation of the LSF from regions of interest of the liver and lungs. The second method was based on segmentation of the liver and lungs from SPECT/CT images of the thorax and abdomen. The differences in planar imaging versus SPECT/CT derived LSF values along with the estimated absorbed lung mean dose (LMD) were evaluated. The LSF values were higher in planar imaging versus SPECT/CT in 81/85 cases, with a mean value of 8.5% vs. 4.6% respectively; the difference was statistically significant using a paired t-test (alpha = 0.05). In those patients who received SIRT, the estimated absorbed LMD calculated with planar imaging was significantly higher than with SPECT/CT (t-test, P < 0.005). Repeated phantom experiments using an anthropomorphic torso phantom with variable 99m Tc activity concentrations for the liver and lungs were performed with the standard patient protocol, demonstrated improved accuracy of the LSF calculation based on SPECT/CT than planar imaging (mean overestimated value of 6% vs. 26%). Conclusions This study demonstrates that LSF calculation using planar imaging can be significantly overestimated while calculation using SPECT/CT imaging and appropriate segmentation tools can be more accurate. Minimizing the errors in obtaining the LSF can lead to more effective 90 Y SIRT treatment planning for hepatic tumors while ensuring the lung dose will not exceed the standard acceptable safety thresholds.
A 66-year old woman had a left breast mass. Biopsy showed invasive ductal carcinoma. A PET/CT scan demonstrated hypermetabolism in the left breast and atypical heterogeneously increased uptake throughout the skeleton as well as a minimally FDG-avid right adrenal myelolipoma. PET/CT 4 months later after 6 cycles of neoadjuvant chemotherapy demonstrated increased size and FDG avidity of this adrenal mass concerning for metastasis and uniformly increased skeletal FDG avidity. Biopsy demonstrated adrenal myelolipoma. The growth and increased FDG avidity of the adrenal myelolipoma were due to the action of colony-stimulating factors on the tumor's hematopoietic component.
Maffucci’s syndrome is a rare congenital nonhereditary syndrome with less than 300 cases having been reported in the United States. It is characterized by multiple enchondromas, hemangiomas, and rarely lymphangiomas. Enchondromas may undergo malignant transformation to chondrosarcomas. Surveillance plays a vital role in detecting early malignant transformation. Fluorodeoxyglucose (FDG) PET/CT, although falling out of favor, may be utilized as an imaging modality by physicians to determine such transformation, allowing for timely management and intervention. In this report, we share our experience with such a case.
<div>AbstractPurpose:<p>Significant progress has occurred in developing quantitative PET/CT biomarkers in diffuse large B-cell lymphoma (DLBCL). Total metabolic tumor volume (MTV) is the most extensively studied, enabling assessment of FDG-avid tumor burden associated with outcomes. However, prior studies evaluated the outcome of cytotoxic chemotherapy or chimeric antigen receptor T-cell therapy without data on recently approved FDA agents. Therefore, we aimed to assess the prognosis of PET/CT biomarkers in patients treated with loncastuximab tesirine.</p>Experimental Design:<p>We centrally reviewed screening PET/CT scans of patients with relapsed/refractory DLBCL enrolled in the LOTIS-2 (NCT03589469) study. MTV was obtained by computing individual volumes using the SUV ≥4.0 threshold. Other PET/CT metrics, clinical factors, and the International Metabolic Prognostic Index (IMPI) were evaluated. Logistic regression was used to assess the association between biomarkers and treatment response. Cox regression was used to determine the effect of biomarkers on time-to-event outcomes. We estimated biomarker prediction as continuous and binary variables defined by cutoff points.</p>Results:<p>Across 138 patients included in this study, MTV with a cutoff point of 96 mL was the biomarker associated with the highest predictive performance in univariable and multivariable models to predict failure to achieve complete metabolic response (OR, 5.42; <i>P</i> = 0.002), progression-free survival (HR, 2.68; <i>P</i> = 0.002), and overall survival (HR, 3.09; <i>P</i> < 0.0001). IMPI demonstrated an appropriate performance, however, not better than MTV alone.</p>Conclusions:<p>Pretreatment MTV demonstrated robust risk stratification, with those patients demonstrating high MTV achieving lower responses and survival to loncastuximab tesirine in relapsed/refractory DLBCL.</p></div>
Breast extranodal marginal zone lymphoma (EMZL) is a rare malignancy. We performed the largest published to date single-center retrospective analysis of 13 patients with breast EMZL focusing on clinical characteristics and treatment-related outcomes. The rarity of this disease at our center was concordant with the prevalence reported in the literature, with breast EMZL comprising 2% of 654 MZL cases. Most patients presented with stage I-II disease however four (30.8%) patients had stage IV disease mostly due to occult bone marrow (BM) involvement. Interestingly, EMZL was frequently non-FDG avid (66.7%) on staging PET/CT. With a median follow-up of 3.1 years (range 5 months to 10.2 years), the 3-year progression free survival was 68.7% (95%CI 30.2%–88.9%) and overall survival 80.2% (95%CI 40.3%-94.8%). No patient experienced higher-grade transformation. Herein we show that localized breast EMZL can be effectively treated with radiation therapy providing long term disease control.
A 66-year-old woman had an episode of pancreatitis with symptoms starting in October 2023. MRI showed an enhancing soft tissue mass along the superior border of the pancreatic body, as well as signal changes in the pancreatic body and the tail consistent with pancreatitis. The 68 Ga-DOTATATE PET/CT demonstrated intense radiotracer uptake within the peripancreatic soft tissue mass, significantly greater than the spleen background. Biopsy of this peripancreatic mass revealed well-differentiated grade 1 neuroendocrine tumor. The body and tail of the pancreas showed diffusely increased 68 Ga-DOTATATE uptake but obviously lower than the peripancreatic neuroendocrine tumor, consistent with pancreatitis.
