INTRODUCTION: 68Ga-PSMA PET is an effective imaging modality in the evaluation of prostate cancer. However, there is limited data on its use in the evaluation of therapeutic response, particularly in radioligand therapy. OBJECTIVE: Our aim is to investigate the diagnostic accuracy of 68Ga-PSMA PET hybrid imaging in evaluating response to 177Lu-PSMA therapy in patients with mCRPC compared with the standard use of serum PSA. METHODOLOGY: A systematic review was done according to the Cochrane diagnostic accuracy reviews guidelines and the PRISMA checklist of literature from January 2015 to August 2020. Literature search, study selection, and data extraction were conducted by 2 reviewers. Statistical analysis of data was done using Meta-DiSc v1.4 RESULTS: A total of 5 studies were included following screening. A total of 128 patients were included in the review. Using PSA response as the reference standard, the pooled sensitivity and specificity of 68Ga-PSMA PET hybrid imaging to evaluate treatment response to 177Lu-PSMA therapy was 85% (Cl: 74 to 92%) and 74% (Cl: 62 to 84%), respectively. The computed diagnostic accuracy was 79.7%. CONCLUSION 68Ga-PSMA PET hybrid imaging is an effective diagnostic procedure in evaluating treatment response to 177Lu-PSMA therapy ligand therapy with good sensitivity, specificity, and diagnostic accuracy.
Gallium ; lutetium ; prostatic neoplasms

PURPOSE: The purpose of this study was to develop a small animal PET using dual layer phoswich detector to minimize parallax error that degrades spatial resolution at the outer part of field-of-view (FOV). MATERIALS AND METHODS: A simulation tool GATE (Geant4 Application for Tomographic Emission) was used to derive optimal parameters of small PET, and PET was developed employing the parameters. Lutetium Oxyorthosilicate (LSO) and Lutetium-Yttrium Aluminate-Perovskite (LuYAP) was used to construct dual layer phoswitch crystal. 8 X 8 arrays of LSO and LuYAP pixels, 2 mm X 2 mm X 8 mm in size, were coupled to a 64-channel position sensitive photomultiplier tube. The system consisted of 16 detector modules arranged to one ring configuration (ring inner diameter 10 cm, FOV of 8 cm). The data from phoswich detector modules were fed into an ADC board in the data acquisition and preprocessing PC via sockets, decoder block, FPGA board, and bus board. These were linked to the master PC that stored the events data on hard disk. RESULTS: In a preliminary test of the system, reconstructed images were obtained by using a pair of detectors and sensitivity and spatial resolution were measured. Spatial resolution was 2.3 mm FWHM and sensitivity was 10.9 cps/micro Ci at the center of FOV. CONCLUSION: The radioactivity distribution patterns were accurately represented in sinograms and images obtained by PET with a pair of detectors. These preliminary results indicate that it is promising to develop a high performance small animal PET.
Animals* ; Electrons* ; Lutetium ; Positron-Emission Tomography* ; Radioactivity

The concept of theranostics, where individual patient-level biological information is used to choose the optimal therapy for that individual, has become more popular in the modern era of ‘personalised’ medicine. With the growth of theranostics, nuclear medicine as a specialty is uniquely poised to grow along with the ever-increasing number of concepts combining imaging and therapy. This special report summarises the status and growth of Theranostic Nuclear Medicine in Singapore.We will cover our experience with the use of radioiodine, radioiodinated metaiodobenzylguanidine, peptide receptor radionuclide therapy, prostate specific membrane antigen radioligand therapy, radium-223 and yttrium-90 selective internal radiation therapy.We also include a section on our radiopharmacy laboratory, crucial to our implementation of theranostic principles. Radionuclide theranostics has seen tremendous growth and we hope to be able to grow alongside to continue to serve the patients in Singapore and in the region.
Hope ; Humans ; Lutetium ; Membranes ; Nuclear Medicine ; Prostate ; Radium ; Receptors, Peptide ; Singapore ; Theranostic Nanomedicine ; Yttrium

PURPOSE: The aim of this study was to evaluate safety and therapeutic efficacy of lutetium 177 prostate-specific membrane antigen (Lu-177-PSMA) in metastatic castration-resistant prostate cancer (mCRPC) patients with low performance status.METHODS: Twenty-two patients already treated with anti-androgens and docetaxel were enrolled for one cycle of Lu-177-PSMA therapy. Haemoglobin, total leukocyte counts, platelets and serum creatinine for toxicity profile while prostate specific antigen (PSA), Eastern Cooperative Oncology Group (ECOG) performance status, visual analogue scale (VAS) and analgesic quantification scale (AQS) for therapeutic efficacy were recorded pre and 8 weeks post therapy. Wilcoxon signed-rank and ANOVA tests were used for statistical analysis.RESULTS: Partial response (PR), stable disease (SD) and progressive disease (PD) for PSAwere seen in 5 (22.7%), 13 (59.1%) and 4 (18.2%) patients respectively treated with mean 6.88 GBq dose of Lu-177-PSMA. 8/22 (36.4%) patients showed ≥ 30% drop in PSA. Grade 3 haemoglobin toxicity was seen in 5/22 (22.7%) patients. No patient developed grade 4 haemoglobin toxicity. No patients had grade 3 or 4 leukocytopenia or thrombocytopenia. Wilcoxon signed-rank test showed statistical significant (P < 0.05) difference in pre and post treatment ECOG, VAS, and AQS scores. The ANOVA test showed statistically significant difference in mean doses of Lu-177-PSMA used in three PSA response groups while difference was non-significant for other variables.CONCLUSION: We concluded that Lu-177-PSMA therapy has adequate pain palliation in end-stage mCRPC patients with low performance status and it has a potential to become effective therapeutic option in properly selected patients.
Creatinine ; Humans ; Leukocyte Count ; Leukopenia ; Lutetium ; Membranes ; Prostate ; Prostate-Specific Antigen ; Prostatic Neoplasms ; Thrombocytopenia

PURPOSE AND METHODS: Patients with inoperable andmetastasized neuroendocrine tumors (NETs), particularly those with grades 1 and 2, usually receive treatment with somatostatin analogues (SSAs). Peptide receptor radionuclide therapy (PRRT) has gained momentum over the past two decades in patients who progress on SSAs. 177Lu-DOTATATE is currently the most widely used radiopeptide for PRRT. We reviewed the recent evidence on PRRT and the treatment of gastroentero-pancreatic neuroendocrine tumors (GEP-NETs).RESULTS: ¹⁷⁷Lu-DOTATATE can be used as neoadjuvant treatment in patients with inoperable GEP-NETs, who might be candidate for surgery after treatment and as adjuvant therapy after surgical intervention. Combination treatments of PRRT with chemotherapy or targeted agents as well as combinations of radionuclides in patients with NETs have been explored over the last few years. The majority of patients with NETs experience partial response or have disease stabilization, a small percentage has complete response, while some 30% of patients, however, will have disease progression. The safety and efficacy of retreatment with extra cycles of PRRT as salvage therapy have been evaluated in small retrospective series.CONCLUSION: Overall, there is evidence that disease control and quality of life improve significantly after 117Lu PRRT therapy. Clinical trials on this therapy are scarce, and there is a need for further studies to establish proper management guidelines.
Disease Progression ; Drug Therapy ; Humans ; Lutetium ; Neoadjuvant Therapy ; Neuroendocrine Tumors ; Nuclear Medicine ; Quality of Life ; Radioisotopes ; Receptors, Peptide ; Retreatment ; Retrospective Studies ; Salvage Therapy ; Somatostatin ; Theranostic Nanomedicine