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Radiation dosimetry of florbetapir F 18.

Joshi AD, Pontecorvo MJ, Adler L, Stabin MG, Skovronsky DM, Carpenter AP, Mintun MA, Florbetapir F 18 study investigato - EJNMMI Res (2014)

Bottom Line: The resultant time-activity curves (TACs) were fitted with constrained exponentials.The effective dose (ED) for each subject was estimated from the acquired data using the adult model.At a dose of 370 MBq florbetapir, the total average ED is approximately 6.88 mSv.

View Article: PubMed Central - HTML - PubMed

Affiliation: Avid Radiopharmaceuticals, Inc,, 3711 Market Street, 7th Floor, Philadelphia, PA 19104, USA. joshi@avidrp.com.

ABSTRACT

Background: Florbetapir is one of several 18F-labeled amyloid plaque imaging tracers for positron emission tomography (PET). As the bio-distribution and radiation dose of PET tracers in human research are important for estimating the relative risks and benefits, a study was conducted to obtain this information on florbetapir.

Methods: Nine cognitively normal subjects (six females and three males, age 58 ± 10 years, weight 81 ± 17 kg) received an intravenous bolus injection of 395 ± 27.9 MBq of florbetapir, and whole-body emission scans were performed over approximately 6 h. Computed tomography scans were acquired for attenuation correction. Volumes of interest (VOIs) for source organs including the brain, liver, lung, heart wall, and vertebrae were defined on the PET images. The VOIs of the gallbladder, urinary bladder, and large and small intestines were also defined. Using reference man organ volumes (ICRP 30), total activity was calculated per organ for each time point. The resultant time-activity curves (TACs) were fitted with constrained exponentials. Kinetic data were entered into OLINDA/EXM software to calculate dose estimates; the dynamic urinary bladder and ICRP 30 GI tract models were employed. The effective dose (ED) for each subject was estimated from the acquired data using the adult model.

Results: The mean ED determined for nine healthy volunteers was 18.60 ± 4.26 μSv/MBq or 6.88 mSv for a 370-MBq dose. The organs that received the highest radiation absorbed doses were the gallbladder, upper large intestine, small intestine, liver, and urinary bladder at 143.0 ± 80.20, 74.50 ± 34.20, 65.50 ± 29.60, 64.40 ± 22.10, and 27.10 ± 11.70 μSv/MBq, respectively.

Conclusions: The ED for florbetapir has been calculated for nine healthy volunteers. At a dose of 370 MBq florbetapir, the total average ED is approximately 6.88 mSv.

No MeSH data available.


Related in: MedlinePlus

Time-activity curves showing mean count activity (Bq/cm3) over time in eight organs for a representative subject. Mean radioactivity concentration values are different across the organs, so the upper limit of the scale is variable.
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Figure 1: Time-activity curves showing mean count activity (Bq/cm3) over time in eight organs for a representative subject. Mean radioactivity concentration values are different across the organs, so the upper limit of the scale is variable.

Mentions: Following reconstruction, volumes of interest (VOIs) for various body organs were defined on the PET images for each patient. Based on the visual examination, the anatomical information from the CT data and the human whole-body reference atlas [10,11] was used to delineate patient specific VOIs. Organs defined by the VOI process were the brain, liver, lung, heart wall, urinary bladder, vertebrae, intestine, and gallbladder. Using these regions on the PET emission data, average counts for the organs were determined at each time imaged. The regional activities were then calculated for each time point, thus providing a time-activity curve (TAC) for each region of a given subject (Figure 1). All organ TACs were fitted with one or two exponential terms using SAAM II software [12]. Time integrals of activity for all the organs were calculated from a lower limit of zero to an upper limit of infinity and expressed as the number of disintegrations in source organs [13]. These values were entered in OLINDA/EXM software [14], using the adult model. Activity observed in a segment of the gastrointestinal (GI) tract was used to estimate total intestinal excretion, using the ICRP 30 GI kinetic model in the OLINDA/EXM software.


Radiation dosimetry of florbetapir F 18.

Joshi AD, Pontecorvo MJ, Adler L, Stabin MG, Skovronsky DM, Carpenter AP, Mintun MA, Florbetapir F 18 study investigato - EJNMMI Res (2014)

Time-activity curves showing mean count activity (Bq/cm3) over time in eight organs for a representative subject. Mean radioactivity concentration values are different across the organs, so the upper limit of the scale is variable.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061749&req=5

Figure 1: Time-activity curves showing mean count activity (Bq/cm3) over time in eight organs for a representative subject. Mean radioactivity concentration values are different across the organs, so the upper limit of the scale is variable.
Mentions: Following reconstruction, volumes of interest (VOIs) for various body organs were defined on the PET images for each patient. Based on the visual examination, the anatomical information from the CT data and the human whole-body reference atlas [10,11] was used to delineate patient specific VOIs. Organs defined by the VOI process were the brain, liver, lung, heart wall, urinary bladder, vertebrae, intestine, and gallbladder. Using these regions on the PET emission data, average counts for the organs were determined at each time imaged. The regional activities were then calculated for each time point, thus providing a time-activity curve (TAC) for each region of a given subject (Figure 1). All organ TACs were fitted with one or two exponential terms using SAAM II software [12]. Time integrals of activity for all the organs were calculated from a lower limit of zero to an upper limit of infinity and expressed as the number of disintegrations in source organs [13]. These values were entered in OLINDA/EXM software [14], using the adult model. Activity observed in a segment of the gastrointestinal (GI) tract was used to estimate total intestinal excretion, using the ICRP 30 GI kinetic model in the OLINDA/EXM software.

Bottom Line: The resultant time-activity curves (TACs) were fitted with constrained exponentials.The effective dose (ED) for each subject was estimated from the acquired data using the adult model.At a dose of 370 MBq florbetapir, the total average ED is approximately 6.88 mSv.

View Article: PubMed Central - HTML - PubMed

Affiliation: Avid Radiopharmaceuticals, Inc,, 3711 Market Street, 7th Floor, Philadelphia, PA 19104, USA. joshi@avidrp.com.

ABSTRACT

Background: Florbetapir is one of several 18F-labeled amyloid plaque imaging tracers for positron emission tomography (PET). As the bio-distribution and radiation dose of PET tracers in human research are important for estimating the relative risks and benefits, a study was conducted to obtain this information on florbetapir.

Methods: Nine cognitively normal subjects (six females and three males, age 58 ± 10 years, weight 81 ± 17 kg) received an intravenous bolus injection of 395 ± 27.9 MBq of florbetapir, and whole-body emission scans were performed over approximately 6 h. Computed tomography scans were acquired for attenuation correction. Volumes of interest (VOIs) for source organs including the brain, liver, lung, heart wall, and vertebrae were defined on the PET images. The VOIs of the gallbladder, urinary bladder, and large and small intestines were also defined. Using reference man organ volumes (ICRP 30), total activity was calculated per organ for each time point. The resultant time-activity curves (TACs) were fitted with constrained exponentials. Kinetic data were entered into OLINDA/EXM software to calculate dose estimates; the dynamic urinary bladder and ICRP 30 GI tract models were employed. The effective dose (ED) for each subject was estimated from the acquired data using the adult model.

Results: The mean ED determined for nine healthy volunteers was 18.60 ± 4.26 μSv/MBq or 6.88 mSv for a 370-MBq dose. The organs that received the highest radiation absorbed doses were the gallbladder, upper large intestine, small intestine, liver, and urinary bladder at 143.0 ± 80.20, 74.50 ± 34.20, 65.50 ± 29.60, 64.40 ± 22.10, and 27.10 ± 11.70 μSv/MBq, respectively.

Conclusions: The ED for florbetapir has been calculated for nine healthy volunteers. At a dose of 370 MBq florbetapir, the total average ED is approximately 6.88 mSv.

No MeSH data available.


Related in: MedlinePlus