From the Department of Nuclear Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India.
Clin Nucl Med. 2022 Nov 1;47(11):948-953. doi: 10.1097/RLU.0000000000004353. Epub 2022 Aug 16.
Prostate cancer (PCa) is the most common cancer in men worldwide. Targeting prostate-specific membrane antigen (PSMA) using radiopharmaceuticals has shown promising results for PCa imaging as well as theranostics. 68 Ga-based PSMA imaging is limited by production of small quantities by generator, and it has led to quest for cyclotron produced 18 F-based PSMA ligands. In the current study, we evaluated the biodistribution and internal dosimetry of 18 F-PSMA-1007 and compared it with 68 Ga-PSMA-11-HBED-CC.
A total of 8 patients with histopathologically proven PCa were included in the study, of whom 4 patients underwent 18 F-PSMA-1007, and the other 4 patients underwent 68 Ga-PSMA-11-HBED-CC PET/CT. The biodistribution of both tracers was quantified for different organs by computing SUVs. All the patients underwent 5-point serial imaging to compute equivalent dose to essential organs and whole-body effective dose using OLINDA-based dosimetry.
The radiotracer uptake in brain, lacrimal gland, salivary gland, heart, lung, liver, gallbladder, spleen, pancreas, intestine, gluteal muscle, and bone marrow were found to be higher in 18 F-PSMA-1007 PET as compared with 68 Ga PSMA-11 PET. Kidney and urinary bladder showed higher SUV value on 68 Ga-PSMA-11-HBED-CC as compared with 18 F-PSMA-1007.The whole-body effective dose from 18 F-PSMA-1007 (1.46E-02 mSv/MBq) was higher than 68 Ga-PSMA-11-HBED-CC (1.03E-02 mSv/MBq). The highest mean equivalent dose from 18 F-PSMA-1007 was observed in the kidneys (1.48E-01 mGy/MBq), followed by spleen (mean, 1.06E-01 mGy/MBq) and liver (6.80E-02 mGy/MBq), whereas 68 Ga-PSMA-11-HBED-CC equivalent dose was maximum in the kidneys (2.13E-01 mGy/MBq), followed by liver (3.03E-02 mGy/MBq), spleen (2.90E-02 mGy/MBq), adrenals (2.67E-02 mGy/MBq), and urinary bladder (1.89E-02 mGy/MBq).
Whole-body effective dose from 18 F-PSMA-1007 is higher compared with 68 Ga-PSMA-11-HBED-CC. 18 F-PSMA-1007 shows lesser urinary bladder clearance compared with 68 Ga-PSMA-11-HBED-CC, which can allow better interpretation of prostatic bed without significant radioactive urine interference. 18 F-PSMA-1007 is a cyclotron-produced alternative to generator-produced 68 Ga-PSMA-11-HBED-CC and can emerge as a good diagnostic surrogate for patients planned for 177 Lu-PSMA-617 therapy.
前列腺癌（PCa）是全球男性最常见的癌症。使用放射性药物靶向前列腺特异性膜抗原（PSMA）已显示出在 PCa 成像以及治疗学方面的有前途的结果。基于 68Ga 的 PSMA 成像受到通过发生器生产少量放射性药物的限制，这导致人们寻求回旋加速器生产的基于 18F 的 PSMA 配体。在当前研究中，我们评估了 18F-PSMA-1007 的生物分布和内部剂量，并将其与 68Ga-PSMA-11-HBED-CC 进行了比较。
共纳入 8 例经组织病理学证实的 PCa 患者，其中 4 例接受了 18F-PSMA-1007 检查，另外 4 例接受了 68Ga-PSMA-11-HBED-CC PET/CT 检查。通过计算 SUV 来定量评估两种示踪剂在不同器官中的分布。所有患者均进行 5 点连续成像，使用 OLINDA 基于剂量的方法计算重要器官的等效剂量和全身有效剂量。
与 68Ga PSMA-11 PET 相比，18F-PSMA-1007 PET 中脑、泪腺、唾液腺、心脏、肺、肝、胆囊、脾、胰腺、肠、臀肌和骨髓的放射性示踪剂摄取更高。与 18F-PSMA-1007 相比，68Ga-PSMA-11-HBED-CC 对肾脏和膀胱的 SUV 值更高。与 68Ga-PSMA-11-HBED-CC 相比，18F-PSMA-1007 的全身有效剂量（1.46E-02 mSv/MBq）更高。从 18F-PSMA-1007 中观察到的最高平均等效剂量是肾脏（1.48E-01 mGy/MBq），其次是脾脏（平均 1.06E-01 mGy/MBq）和肝脏（6.80E-02 mGy/MBq），而 68Ga-PSMA-11-HBED-CC 的等效剂量在肾脏中最高（2.13E-01 mGy/MBq），其次是肝脏（3.03E-02 mGy/MBq）、脾脏（2.90E-02 mGy/MBq）、肾上腺（2.67E-02 mGy/MBq）和膀胱（1.89E-02 mGy/MBq）。
与 68Ga-PSMA-11-HBED-CC 相比，18F-PSMA-1007 的全身有效剂量更高。与 68Ga-PSMA-11-HBED-CC 相比，18F-PSMA-1007 对膀胱的清除率较低，这可以在没有明显放射性尿液干扰的情况下更好地解释前列腺床。18F-PSMA-1007 是发生器生产的 68Ga-PSMA-11-HBED-CC 的替代物，可作为计划进行 177Lu-PSMA-617 治疗的患者的良好诊断替代物。
