title: Equivalent Dose Rate 1 Meter from Neuroendocrine Tumor Patients Exiting the Nuclear Medicine Department After Undergoing Imaging.
abstract: 123I-metaiodobenzylguanidine (MIBG) and111In-pentetrotide SPECT have been used for functional imaging of neuroendocrine tumors (NETs) for the last 2 decades. More recently, PET/CT imaging with18F-FDG,18F-fluorodihydroxyphenylalanine (FDOPA), and68Ga somatostatin-receptor ligands in NETs has been expanding. A literature search could find no direct measurements of the dose rate from NET patients exiting the nuclear medicine department after undergoing PET/CT with18F-FDOPA or68Ga-DOTATOC, a somatostatin analog.Methods:We measured the dose rates from 93 NET patients on leaving the department after undergoing PET/CT or SPECT/CT in our centers. In total, 103 paired measurements of equivalent dose rate at 1 m (EDR-1m) from the sternum and urinary bladder were obtained. The detector faced the sternum or bladder and was 1 m away from and directly in front of the patient. The practice for exiting the department differed according to whether the patient had been referred for PET/CT or for SPECT/CT. PET/CT patients were discharged after imaging, whereas SPECT/CT patients left the department earlier, just after radiopharmaceutical injection.Results:The median administered activity was 122 MBq in 5368Ga-DOTATOC PET/CT studies, 198 MBq in 1518F-FDOPA PET/CT studies, and 176 MBq in 1318F-FDG PET/CT studies. The corresponding median EDR-1m was 4.8, 9.5, and 8.8 μSv/h, respectively, facing the sternum, and 5.1, 10.1, and 9.5 μSv/h, respectively, facing the bladder. The median administered activity was 170 MBq in 12111In-pentetreotide SPECT/CT studies and 186 MBq in 10123I-MIBG SPECT/CT studies. The corresponding median EDR-1m was 9.4, and 4.9 μSv/h, respectively, at the level of the sternum, and 9.3 and 4.7 μSv/h, respectively, at the level of the bladder. The EDR-1m was less than 20 μSv/h in all patients. Thus, when exiting the nuclear medicine department, the NET patients injected with68Ga-DOTATOC or123I MIBG emitted an average EDR-1m roughly half that of patients injected with other radiopharmaceuticals. This finding is a complementary argument for replacing SPECT by PET somatostatin-receptor imaging.Conclusion:Our current practice of allowing patients to exit after PET/CT imaging or just after SPECT radiopharmaceutical injection appears to be safe from a radiation protection point of view. Restrictive advice is unnecessary for NET patients being discharged from the department.
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP, Paris, France juleszhangyin@gmail.com.|Université Pierre et Marie Curie, Paris, France.
authors.forename: Jules
authors.initials: J
authors.lastname: Zhang-Yin
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP, Paris, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Dirand
authors.affiliation: Department of Nuclear Medicine, Hôpital Cochin, AP-HP, Paris, France; and.
authors.forename: Myriam
authors.initials: M
authors.lastname: Sasanelli
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP, Paris, France.
authors.forename: Gwenaelle
authors.initials: G
authors.lastname: Corrégé
authors.affiliation: Department of Nuclear Medicine, Hôpital Cochin, AP-HP, Paris, France; and.
authors.forename: Aude
authors.initials: A
authors.lastname: Peudon
authors.affiliation: Université Pierre et Marie Curie, Paris, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Kiffel
authors.affiliation: Radiopharmacy, Hôpital Tenon, AP-HP, Paris.
authors.forename: Valérie
authors.initials: V
authors.lastname: Nataf
authors.affiliation: Department of Nuclear Medicine, Hôpital Cochin, AP-HP, Paris, France; and.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Clerc
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP, Paris, France.|Université Pierre et Marie Curie, Paris, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Montravers
authors.affiliation: Department of Nuclear Medicine, Hôpital Tenon, AP-HP, Paris, France.|Université Pierre et Marie Curie, Paris, France.
authors.forename: Jean-Noël
authors.initials: JN
authors.lastname: Talbot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging*; D009683:Nuclear Medicine; D000072078:Positron Emission Tomography Computed Tomography; D011829:Radiation Dosage; D011874:Radiometry; D019275:Radiopharmaceuticals; D000072098:Single Photon Emission Computed Tomography Computed Tomography; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals
keywords: dose rate; neuroendocrine tumors (NET); radiation protection; somatostatin receptor–based PET/CT; somatostatin receptor–based SPECT/CT