Rapid SPECT/CT Scans After 177Lu-PSMA-617 Therapy Allow Effective Response Assessment in Metastatic Prostate Cancer Case Study

SIEMENS Healthineers Fast, quantitative SPECT/CT acquisition following multiple therapy cycles of 177Lu-PSMA-617 enables response assessment in a patient with metastatic prostate cancer By Andrés Ricaurte Fajardo, MD,1 Joseph Osborne, MD, PhD,1 Lady Sawoszczyk, BS, CNMT2 Data and images courtesy of New York-Presbyterian Hospital/Weill Cornell Medical Center, New York, New York, USA History A male in his 70s with a history of antigen (PSA) levels began to rise, 223Ra-dichloride, docetaxel, and prostate-specific membrane antigen the patient was unsuccessfully cabazitaxel with no significant (PSMA)-positive metastatic castra- treated with androgen deprivation improvement. The patient also tion-resistant prostate cancer therapy (ADT) and multiple lines completed a palliative course of (mCRPC) underwent 177Lu-PSMA-617 of systemic chemotherapy. As the radiotherapy (30 Gy in 10 fractions) treatment 14 years after his initial disease progressed, the patient without any treatment complications. diagnosis. When prostate-specific received treatment with 1 Department of Molecular Imaging and Therapeutics, New York-Presbyterian Hospital/Weill Cornell Medicine, New York, New York, USA 2 Siemens Healthineers Molecular Imaging, Hoffman Estates, Illinois, USA 1 Theranostics Case Study · siemens-healthineers.com/micc Clinical Results 1 Coronal CT, 68Ga-PSMA-11 PET, and PET/CT images confirm PSMA expression in metastatic disease and qualify the patient for 177Lu-PSMA-617 treatment. Findings A routine 68Ga-PSMA-11 PET/CT was performed to qualify the patient for 177Lu-PSMA-617 treatment. PET/CT findings confirmed PSMA expression in the tumors. The patient was administered with 3.76 mCi (139.12 MBq) intravenous (IV) injection of 68Ga-PSMA-11, and approximately 1 hour later, a single- scan, whole-body acquisition was conducted on Biograph mCT Flow™ PET/CT. As observed in Figures 1-3, 68Ga-PSMA-11 PET/CT images demonstrate an increased extent of PSMA-avid osseous metastasis within the T3-T7 vertebrae with extension into the neural foramen and ventral epidural space suspected at the T4-T6 levels. 2 Sagittal CT, 68Ga-PSMA-11 PET, and PET/CT images demonstrate the extent of metastatic disease prior to 177Lu-PSMA-617 treatment. Theranostics Case Study · siemens-healthineers.com/micc 2 Clinical Results T4 T4-T5 T5 T5/T6 T6 3 Axial CT and 68Ga-PSMA-11 PET/CT images demonstrate the extent of metastatic disease in the T4-T6 vertebrae. There is an overall increased extent after each treatment cycle. The Due to the patient’s neutropenia, of PSMA-avid cervical, thoracic, and 3-bed, quantitative SPECT/CT which was based on absolute abdominopelvic nodal metastasis. study was acquired at 60 stops per neutrophil count (ANC) values in detector with 5 seconds per stop. between cycles, the recommended The patient underwent 6 cycles Total scan time was 15 minutes. dose of 200 mCi (7.4 GBq) was of 177Lu-PSMA-617 therapy; each Following CT attenuation correction modified by 20% to 160 mCi (5.9 cycle was delivered every 6-8 weeks. (CTAC), the corrected SPECT data GBq). Therapy response continued Multi-bed, quantitative SPECT/CT was fused with CT data for visual to be monitored via PSA values and imaging was conducted on Symbia interpretation. quantitative SPECT/CT imaging. Intevo Bold™ with xSPECT Quant™ Prostate-specific antigen (PSA) Absolute neutrophil count (ANC) Treatment cycle 177Lu-PSMA-617 dose values (ng/mL) (Normal ANC range: 2,500-6,000 cells/µL) 1 203 mCi (7.5 GBq) 2,009 2,540 2 160 mCi (5.92 GBq) 1,514.29 1,000 3 193.5 mCi (7.1 GBq) 934.73 800 4 160.6 mCi (5.94 GBq) 658.83 1,220 5 156.9 mCi (5.8 GBq) 618.36 800 6 165.2 mCi (6.11GBq) 374.46 1,300 3 Theranostics Case Study · siemens-healthineers.com/micc Clinical Results As observed in Figures 4 and 5, the the expected distribution of targeted SPECT/CT with xSPECT Quant images PSMA in concordance with findings demonstrate a normal biodistribu- from the preceding PSMA PET tion of 177Lu-PSMA-617 and foci of (Figures 1 and 2). increased uptake compatible with Sagittal CT Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 6 4 Sagittal CT through the thoracic and lumbar spine shows extensive sclerosis in the vertebral bodies reflecting metastatic disease with particularly dense sclerosis in the T5 vertebral body. Cycle 2 image shows significant decrease in mid-thoracic vertebral uptake compared to that of low thoracic and lumbar vertebrae, which can be explained by additional mid-thoracic external beam radiation delivered throughout the 177Lu-PSMA therapy regimen. Cycle 3 images acquired 7 days post injection demonstrate lower bladder uptake when increasing time lapse post injection. High uptake in the lower thoracic and lumbar vertebrae is visualized after cycles 2 and 3 but shows considerable decrease after cycles 4 and 6, which clearly demonstrates tumor response. 51 SUV max O Cycle 1 Cycle 2 Cycle 3 Cycle 4 Cycle 6 5 177Lu-PSMA-617 SPECT maximum intensity projection (MIP) images demonstrate positive treatment response. Cycle 1 and 2 images acquired 2 hours post injection. Cycle 3, 4, and 6 images acquired 7 days post injection. Comparison of cycle 1 and cycle 6 SPECT MIP images reveals decreased uptake through the axial skeleton and pelvis as well as the left and right humerus. Theranostics Case Study · siemens-healthineers.com/micc 4 Clinical Results Discussion Examination protocol This case demonstrates the clinical Scanners: Biograph mCT Flow PET/CT and Symbia Intevo Bold SPECT/CT advantage of using quantitative SPECT/CT with 177Lu-PSMA-617 treat- 68Ga-PSMA-11 PET ment for therapy monitoring. The Injected dose 3.76 mCi (139.12 MBq) confirmation of positive or negative Post-injection delay 60 minutes treatment response plays a critical role in disease management, and Acquisition 1.0 mm/s SPECT/CT with xSPECT Quant images FlowMotion™ continuous bed motion helped confirm that the tumors Reconstruction 200 x 200 matrix visualized on the 68Ga-PSMA-11 PET/CT were the same tumors being CT treated with 177Lu-PSMA-617. The Tube voltage 100 kV large field of view available on Symbia Intevo Bold SPECT/CT enabled Tube current 74 mAs a 15-minute, 3-bed-position imaging Slice collimation 3.0 mm protocol, which covered vertex to Slice thickness 3.0 mm thigh and allowed the routine use of post-treatment, image-based 177Lu-PSMA-617 uptake assessment. 177Lu-PSMA-617 SPECT (Cycle 6) As shown in Figure 5, a progressive Injected dose 165.2 mCi (6.11 GBq) reduction of 177Lu-PSMA-617 uptake demonstrated the efficacy of this Post-injection delay 7 days treatment. Furthermore, the method 3 bed positions/5 seconds per view, of imaging after each treatment cycle enabled quality control checks Acquisition 60 views per detector Total scan time: 15 minutes that helped ensure that the treat- (5 minutes per bed) ment was irradiating the tumors as expected. Reconstruction 256 x 256 matrix, xSPECT Zoom 1.0 CT Conclusion Tube voltage 110 kV 177Lu-PSMA-617 treatment plays Tube current 12 mAs a critical role in patients with Slice collimation 3.0 mm mCRPC who have a history of unsuccessful response to hormone Slice thickness 3.0 mm therapy and chemotherapy. The The outcomes achieved by the Siemens Healthineers customers described herein were ability to perform fast, multi-bed, achieved in the customer’s unique setting. Since there is no “typical” hospital and many quantitative SPECT/CT imaging on variables exist (eg, hospital size, case mix, level of IT adoption) there can be no guarantee Symbia Intevo Bold with xSPECT that others will achieve the same results. Quant provides high sensitivity to assess 177Lu-PSMA-617 therapy response. Thus, post-treatment imaging is critical for quality control evaluation to confirm PSMA-avid tumors are being treated properly. 5 Theranostics Case Study · siemens-healthineers.com/micc Legal information: On account of certain regional limitations of sales rights and service availability, we cannot guarantee that all products included in this publication are available through the Siemens Healthineers sales organization worldwide. Availability and packaging may vary by country and is subject to change without prior notice. The information in this document contains general technical descriptions of specifications and options as well as standard and optional features, which do not always have to be present in individual cases. Please contact your local Siemens Healthineers sales representative for the most current information. Note: Any technical data contained in this document may vary within defined tolerances. 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