Absorbed Organ Doses Research Articles

Normalized pediatric organ-absorbed doses from CT examinations.

Absorbed doses to the bone marrow, gonads, thyroid, eyes, breast, and skin from CT examinations of the head, chest, abdomen, and torso were measured in a phantom mimicking an average 6-year-old child. The doses were normalized to the CT dose index measured at the central position of a standardized cylindrical phantom, to allow approximation of organ-absorbed doses for similar scanners for which the CT dose index has been measured. Estimating organ-absorbed doses associated with CT examinations of children is necessary to evaluate the relative risks of carcinogenesis associated with radiation exposure of a particular organ. The risks from a particular CT examination depends on the patient's age because the geometric configuration of the organs (e.g., marrow distribution) changes over time and will, therefore, affect the scatter dose to the organs.

Normalized organ doses for various diagnostic radiologic procedures.

Organ-absorbed doses for 24 diagnostic examination projections were measured using an Alderson Rando phantom. The organs of interest were testes, ovaries, thyroid, eyes, uterus, and active bone marrow. The reported values were normalized to the unit entrance exposure of each examination. Subsequent comparison of these measured values with the experimental and calculated values of other investigators showed reasonable agreement.

Radiation Dose in a Human Fetus Following Use of197Hg

HomeRadiologyVol. 103, No. 1 PreviousNext Nuclear MedicineRadiation Dose in a Human Fetus Following Use of 197HgWilfrido M. Sy, Herman Rosen, Nathaniel E. Griffin, Harold Fink, Alois Vasicka, Steven A. Lorber, Nathan A. SolomonWilfrido M. Sy, Herman Rosen, Nathaniel E. Griffin, Harold Fink, Alois Vasicka, Steven A. Lorber, Nathan A. SolomonAuthor Affiliations Kings County Hospital CenterClarkson Ave. Brooklyn, N. Y. 11203Wilfrido M. SyHerman RosenNathaniel E. GriffinHarold FinkAlois VasickaSteven A. LorberNathan A. SolomonPublished Online:Apr 1 1972https://doi.org/10.1148/103.1.139MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In AbstractThe authors studied the amount of radioactivity in the liver, lung, kidney, and heart of a fetus, the product of a cesarean hysterectomy twenty-four hours after the mother had received 200 µCi of 197Hg. The results are tabulated, and an appendix gives the equations by which the organ-absorbed doses were calculated.Article HistoryAccepted: Oct 1971Published in print: Apr 1972 FiguresReferencesRelatedDetailsCited ByAnnals of the ICRP, Vol. 18, No. 1-4Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 103, No. 1 Metrics Altmetric Score PDF download

Some problems of gastrointestinal bleeding in chiddren.

Myocardial perfusion imaging has long been used off label by practitioners attending for children with cardiac aliments. To provide clinicians with evidence-based dosage recommendation, a phase I–II, open-label, nonrandomized, multicenter trial was therefore designed using ^99mTc-sestamibi in pediatric subjects (registered under www.clinicaltrials.gov identifier no. NCT00162045). <b>Methods:</b> Safety and pharmacokinetic data were collected from 78 subjects using either a 1-d imaging protocol (3.7–7.4 MBq/kg, followed by 11.1 MBq/kg) or a 2-d protocol (7.4 MBq/kg for both rest and stress). Anterior and posterior planar images were collected at 15 min, 1.5 h, 4 h, and 8 h. Blood and urine samples were collected at predetermined times. <b>Results:</b> Subjects included 39 children (mean age ± SD, 8.5 ± 2.04 y) and 39 adolescents (mean age ± SD, 13.6 ± 1.39 y). Mean estimated organ-absorbed doses to the upper large intestine, small intestine, gallbladder wall, and lower large intestines were 0.082, 0.043, 0.042, and 0.035 mSv/MBq, respectively. All patients tolerated the radiotracer without serious adverse effects. Significant differences were observed in the liver, upper large intestine contents, and small intestine contents between rest and stress imaging. The effective dose equivalent and effective dose averages were lower in adolescents than younger children (0.011 and 0.019 mSv/MBq, respectively; <i>P</i> &lt; 0.0001). Percentage injected doses (%IDs) corrected for radioactive decay in all dosimetry-evaluable subjects at 15 min and 4 h were 1.9% and 1.2% in the myocardium. Similarly in the lungs, the %ID for all dosimetry-evaluable subjects was 4.9% at 15 min after injection. At rest, the %ID in the liver decreased from a maximum of about 26% at 15 min to less than 9% at 90 min. With stress, values decreased from 15% to 7%, respectively. <b>Conclusion:</b> The estimates of radiation dosimetry, pharmacokinetic parameters, and safety profile in this study population are similar to published studies based on body-mass extrapolations from studies in adults. As such, applying current ^99mTc-sestamibi dosing regimens for 1- and 2-d protocols based on those extrapolations will result in the expected radiation dose in children and adolescents.