Development and Verification of an MCNP5-based Gamma Camera for 177Lu SPECT Imaging Puvanesuawary Morthy, Marianie Musarudin, Nor Shazleen Ab Shukor, Mohamad Aminudin Said, Xianling Dong, M. Iqbal Saripan Pertanika Journal of Science and Technology, 2025 Monte Carlo (MC) simulations in single-photon emission computed tomography (SPECT) are invaluable for enhancing activity quantification in patients, thereby facilitating an accurate estimate of the absorbed dose for every organ. The validation of MC results against experimental data is essential to ensure their reliability. This study focuses on lutetium-177 (177Lu) SPECT imaging modeling using the Monte Carlo N-Particle Transport, version 5 (MCNP5) code. The objective was to validate the MC code for 177Lu SPECT by comparing simulated and experimental data on system sensitivity, image quality, intensity profiles, and energy resolution. The gamma camera was modeled based on the GE HealthCare Discovery nuclear medicine/computed tomography (NM/CT) 670 Pro, with a medium energy general purpose (MEGP) collimator. MC simulations accounted for the SPECT scanner’s physical specifications, Gaussian energy blurring, and corrections for scatter and attenuation. Post-simulation analysis was performed in the Matrix Laboratory (MATLAB) software, with comparisons made under identical geometrical configurations for experimental and simulated data. The results revealed a strong agreement between simulated and experimental data. System sensitivities varied by only 3.34%, while the structural similarity index metric (SSIM) value of 0.9348 demonstrated a high level of similarity. The energy resolutions for 113 and 208 keV were 16.28 and 15.69%, respectively. Additionally, high correlation coefficients across spheres further validated the accuracy of the MC model. These remarkable agreements confirm the accuracy and precision of the MCNP5-based 177Lu SPECT imaging simulations. In conclusion, the validated MCNP5 model of the gamma camera provides a foundation for future research into 177Lu SPECT imaging and quantification.
Synthesis and clinical evaluation of cyclotron-produced [68Ga]PSMA-11 and [18F]PSMA-1007 for prostate cancer imaging Muhammad Fakhrurazi bin Ahmad Fadzil, Mohd Fazrin bin Mohd Rohani, Muhammad Adib Abdul Onny, Zarif Ashhar, Mohamad Aminudin bin Said, Mazurin Mahamood, Nik Muhammad Fitri Nik Afinde, Noratikah Mat Ail, Zaitulhusna Md Safee, Nor Idayu Razali, Hamdi Noor, Mohd Firdaus Abdul Aziz, Norsalita Ali, Nurul Ain Yaacob, Radziatul Shahirah Abdul Rahman, Chen Siew Ng, Tharmasilen Selvarajoo Nuclear Medicine Communications, 2025 Objective To compare the radiochemical synthesis, stability, and clinical performance of cyclotron-produced [18F]PSMA-1007 and [⁶⁸Ga]PSMA-11 for prostate-specific membrane antigen (PSMA)-targeted PET/computed tomography (CT) imaging in prostate cancer. Methods Six production runs each of [¹⁸F]PSMA-1007 and [⁶⁸Ga]PSMA-11 were conducted using a cyclotron-based system. Radiochemical yield, radiochemical purity, and product stability were evaluated according to European Pharmacopeia standards. Thirty-five patients with prostate cancer underwent dual-tracer PET/CT imaging within 30 days. Images were assessed for lesion detectability, biodistribution, and pitfalls by three independent nuclear medicine physicians using semiquantitative metrics. Results [¹⁸F]PSMA-1007 demonstrated substantially higher end-of-synthesis activity (mean: 75.68 GBq) compared with [⁶⁸Ga]PSMA-11 (mean: 1.76 GBq), with both achieving high RCP (>98%) and comparable synthesis durations. Stability testing confirmed [¹⁸F]PSMA-1007 remained radiochemically stable for up to 9 h. Clinically, both tracers showed high concordance in PSMA-avid lesion detection. [¹⁸F]PSMA-1007 exhibited superior contrast in prostate and skeletal lesions because of minimal urinary excretion but also revealed higher rates of benign uptake in ganglia and nonspecific bone sites, leading to increased discordant findings (104 vs. 47 lesions). Conclusion [¹⁸F]PSMA-1007 provides significant advantages in production scalability and lesion detectability, particularly in skeletal and pelvic regions; however, its higher rate of benign uptake necessitates careful interpretation to avoid false positives. While both tracers are clinically effective, tracer selection should be guided by logistical feasibility, clinical context, and interpretive considerations.
Assessment of lifetime attributable risk (LAR) of cancer incidence from whole-body 18F-FDG PET/CT examinations using established polynomial fittings H. Murat, M.M.A. Kechik, M.T. Chew, I. Kamal, M.A. Said, M.K.A. Karim Radioprotection, 2025 The advent of PET/CT examinations has revolutionized cancer treatment, offering greater precision in diagnosis. Nonetheless, the ionizing radiation exposure during the examination could cause radiation cancer risk. Hence, this study aimed to evaluate the radiation dose and radiation-induced risk associated of whole-body PET/CT examinations that includes the 18F-FDG radionuclides. For this retrospective study, 40 participants were studied, with 20 men and 20 women. The average age and weight of the participants were 53.77 ± 15.78 years and 66.59 ± 16.94 kg respectively, and they were administered 424.64 ± 121.19 MBq of 18F-FDG before the PET/CT commenced. The IDAC-Dose 2.1 program was employed to calculate the absorbed dose and effective dose in organs such as the bladder, brain, lung, kidneys, colon, red bone marrow (RBM), stomach, liver, and thyroid. In this study, polynomial regression was used to fit the Lifetime Attributable Risk (LAR) values derived from the BEIR VII phase II report. The effective dose from the 18F-FDG PET/CT examination was 20.1 ± 7.9 mSv, with a ratio of E to the administered activity of 1.612 × 10−2 mSv/MBq, in accordance with ICRP standards. The related risk of cancer in the second part of the work did not include CT component. The estimated average cancer incidence from the PET alone was 7 and 8 cases per 100,000 persons exposed to 0.1Gy for men and women respectively, with PET-related effective doses ranging between 3.2 mSv to 27.3 mSv. In summary, the risk of cancer associated with current whole-body 18F-FDG PET/CT examinations is low, but it is essential to mitigate radiation exposure during these examinations and utilize suitable techniques to prevent stochastic effects from low-dose radiation exposure.
Quality control of Actinium-225 radiopharmaceuticals: Current challenges and solutions in Malaysia Medical Journal of Malaysia, 2024
Performance evaluation of Gallium-68 radiopharmaceuticals production using liquid target PETtrace 800 cyclotron Zarif Ashhar, Muhammad Fakhrurazi Ahmad Fadzil, Zaitulhusna Md Safee, Firdaus Aziz, Ummi Habibah Ibarhim, Nik Muhammad Fitri Nik Afinde, Noratikah Mat Ail, Muhammad Ali Hazizi Jamal Harizan, Dzulieza Halib, Arieffuddin Alek Amran, Rabiatul Adawiyah, Mohd Hamdi Noor Abd Hamid, Mazurin Mahamood, Nor Idayu Razali, Mohamad Aminudin Said Applied Radiation and Isotopes, 2024
QUANTIFICATION OF ABSORBED DOSE IN90Y SELECTIVE INTERNAL RADIATION THERAPY FOR HEPATOCELLULAR CARCINOMA TREATMENT: A REVIEW Nurul Firzanah Baharuddin, Noorfatin Aida Baharul Amin, Noushin Anan, Kamran Hameed,, Mahayuddin Abdul Manap, Mohamad Aminudin Said, Nor Salita Ali, Dhalisa Hussin, Hazlin Hashim, Nizuwan Azman, Rafidah Zainon Journal of Health and Translational Medicine, 2023 Selective internal radiation therapy (SIRT) has emerged as a viable strategy for the treatment of incurable hepatic cancers. Although SIRT is a well-known therapy, continuous improvement in personalised dosimetry is required to improve the treatment planning and delivery of therapy. The ability to precisely foresee, plan, and administer the ideal dose to the tumour and non-tumoral tissues, including a final validation of the dose distribution, is the primary principle of radiation. The main way for safely personalised therapy for a maximum response while respecting normal tissue tolerances is to know the true absorbed dose to tissue compartments. Recent clinical studies highlighted the significance of personalised dosimetry to make it safer and more effective. Quantification of the absorbed dose distribution is of utmost importance in SIRT 90Y to optimise the hepatocellular carcinoma (HCC) treatment. The aim of this article was to review various dosimetric approaches in quantifying the absorbed dose of tumours and healthy liver tissue in 90Y SIRT. This article also compares the capabilities of organ-level dosimetry, voxel-level dosimetry and Monte Carlo simulation in assessing the absorbed dose in organs especially liver. The quantification of absorbed dose influences 90Y SIRT tumour dosimetry, while healthy liver absorbed dose values were comparable for all investigated imaging data. Personalised dosimetry for the tumour and healthy liver parenchyma after 90Y SIRT is recommended for patient-tailored therapy with enhanced therapeutic outcomes and for the safe administration of additional treatment cycles.
Optimization of scanning time of18f-fdg whole body pet/ct imaging in obese patients using quadratic dose protocol Medical Journal of Malaysia, 2021
The comparison of serial spect-ct imaging to estimate absorbed dose to the organ at risk from peptide receptor radionuclide therapy dosimetry Iranian Journal of Nuclear Medicine, 2021
Implementation of quadratic dose protocol for 18F-FDG whole-body PET imaging using a BGO-based PET/CT scanner, GE Discovery ST Iranian Journal of Nuclear Medicine, 2019
I-124 pre-therapy dosimetry for the treatment of differentiated thyroid cancer: A single center experience Iranian Journal of Nuclear Medicine, 2017
