Department of Radiology, UPMC/Presbyterian Hospital, University of Pittsburgh, Room B-938, 200 Lothrop St., Pittsburgh, PA 15213, USA.
Mol Imaging Biol. 2012 Feb;14(1):115-22. doi: 10.1007/s11307-011-0478-2.
We measure the whole-body distribution of IV injected [¹¹C]Flumazenil (FMZ) as a function of time in adult subjects and determine the absorbed radiation doses.
After injection with 770 MBq of [¹¹C]FMZ (nominal), each of six subjects underwent nine consecutive whole body PET scans. Twelve source organs were identified using PET attenuation and emission images. Activity within each organ as a function of time was determined from the sequence of the nine PET scans. Source organ time activity curves were integrated and normalized by the injected dose to yield source organ residence times for the no voiding situation. Separate bladder residence-time calculations were performed for the cases of a 1- and a 2-h voiding interval. Using the source organ residence times as input, the program OLINDA/EXM (Stabin et al. in J Nucl Med. 46:1023-1027, 2005) was used to perform dosimetry calculations for the various body organs and for the whole body.
For the no voiding situation, the average whole-body radiation equivalent dose was 3.02 × 10⁻³ mSv/MBq of injected [¹¹C]FMZ. The average effective dose and effective dose equivalent was 7.57 × 10⁻³ and 1.12 × 10⁻² mSv MBq⁻¹, respectively. The organ receiving the highest equivalent dose was the urinary bladder wall with an average of 6.32 × 10⁻² mSv MBq⁻¹.
On average, the administration of less than 790 MBq (21 mCi) of [¹¹C]FMZ yields (no voiding model) an organ equivalent dose of under 50 mSv [the single dose limit for research studies under US regulations (21CFR361.1) to body organs other than blood forming organs, gonads or the lens of the eye] to all organs. Equivalent dose to the blood forming organs and gonads from a 790 MBq administered FMZ dose is well under the 30 mSv limit provided under 21CFR361.1. Additionally, administration of less than 1320 MBq (35.7 mCi) yields an effective dose [International Commission on Radiation Protection (ICRP) 60 tissue weighting scheme] of under 10 mSv, which is the ICRP IIb (minor to intermediate) risk category limit.
我们测量了成年受试者静脉注射 [¹¹C]氟马西尼（FMZ）的全身分布随时间的变化，并确定了吸收的辐射剂量。
在注射 770MBq 的 [¹¹C]FMZ（名义上）后，六名受试者中的每一名都进行了九次连续的全身 PET 扫描。使用 PET 衰减和发射图像识别了 12 个源器官。从九次 PET 扫描的序列中确定每个器官随时间的活动。通过将注射剂量归一化，对源器官的时间活性曲线进行积分，得出无排空情况下源器官的滞留时间。对于排空时间为 1 小时和 2 小时的情况，分别进行了单独的膀胱滞留时间计算。使用源器官滞留时间作为输入，使用程序 OLINDA/EXM（Stabin 等人，J Nucl Med. 46:1023-1027, 2005）对各种身体器官和全身进行了剂量计算。
对于无排空情况，全身辐射当量剂量的平均值为每注射 7.90 × 10⁻³ mSv/MBq 的 [¹¹C]FMZ 为 3.02 × 10⁻³ mSv。有效剂量和有效剂量当量的平均值分别为 7.57 × 10⁻³ 和 1.12 × 10⁻² mSv MBq⁻¹。接受最高当量剂量的器官是膀胱壁，平均为 6.32 × 10⁻² mSv MBq⁻¹。
平均而言，给予少于 790MBq（21mCi）的 [¹¹C]FMZ（无排空模型）会使所有器官的器官当量剂量低于 50mSv（美国法规下的研究研究的单次剂量限制（21CFR361.1），除了造血器官、性腺或眼睛晶状体之外的身体器官）。从 790MBq 给予的 FMZ 剂量，血液形成器官和性腺的当量剂量远远低于 21CFR361.1 下规定的 30mSv 限制。此外，给予少于 1320MBq（35.7mCi）会导致有效剂量[国际辐射防护委员会（ICRP）60 组织加权方案]低于 10mSv，这是 ICRP IIb（轻微到中度）风险类别限制。
