Publications [#133547] of Terry T Yoshizumi

Papers Published

1. ST Schindera, RC Nelson, ER Lee, DM Delong, G Ngyen, G Toncheva, TT Yoshizumi, Abdominal multislice CT for obese patients: effect on image quality and radiation dose in a phantom study., Academic radiology, vol. 14 no. 4 (April, 2007), pp. 486-94, ISSN 1076-6332 [doi]
   (last updated on 2013/07/01)

   Abstract:
   OBJECTIVE: To evaluate the effect of a modified abdominal multislice computed tomography (CT) protocol for obese patients on image quality and radiation dose. METHODS: An adult female anthropomorphic phantom was used to simulate obese patients by adding one or two 4-cm circumferential layers of fat-equivalent material to the abdominal portion. The phantom was scanned with a subcutaneous fat thickness of 0, 4, and 8 cm using the following parameters (detector configuration/beam pitch/table feed per rotation/gantry rotation time/kV/mA): standard protocol A: 16 x 0.625 mm/1.75/17.5 mm/0.5 seconds/140/380, and modified protocol B: 16 x 1.25 mm/1.375/27.5 mm/1.0 seconds/140/380. Radiation doses to six abdominal organs and the skin, image noise values, and contrast-to-noise ratios (CNRs) were analyzed. Statistical analysis included analysis of variance, Wilcoxon rank sum, and Student's t-test (P < .05). RESULTS: Applying the modified protocol B with one or two fat rings, the image noise decreased significantly (P < .05), and simultaneously, the CNR increased significantly compared with protocol A (P < .05). Organ doses significantly increased, up to 54.7%, comparing modified protocol B with one fat ring to the routine protocol A with no fat rings (P < .05). However, no significant change in organ dose was seen for protocol B with two fat rings compared with protocol A without fat rings (range -2.1% to 8.1%) (P > .05). CONCLUSIONS: Using a modified abdominal multislice CT protocol for obese patients with 8 cm or more of subcutaneous fat, image quality can be substantially improved without a significant increase in radiation dose to the abdominal organs.

   Keywords:
   Analysis of Variance • Calibration • Female • Humans • Obesity* • Phantoms, Imaging • Radiation Dosage • Radiography, Abdominal • Statistics, Nonparametric • Tomography, X-Ray Computed • standards*