No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The effects of gantry tilt on breast dose and image noise in cardiac CT
3. 2011 CT Market Outlook Report (IMV Medical Information Division, Des Plaines, IL, 2011).
4. A. J. Einstein, M. J. Henzlova, and S. Rajagopalan, “Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography,” JAMA, J. Am. Med. Assoc. 298, 317–323 (2007).
5. F. Faletra, I. D’Angeli, C. Klersy, M. Averaimo, J. Klimusina, E. Pasotti, G. Pedrazzini, M. Curti, C. Carraro, and R. DiLiberto, “Estimates of lifetime attributable risk of cancer after a single radiation exposure from 64-slice computed tomographic coronary angiography,” Heart 96, 927–932 (2010).
6. E. Angel, N. Yaghmai, C. Jude, J. DeMarco, C. Cagnon, J. Goldin, C. McCollough, A. Primak, D. Cody, and D. Stevens, “Dose to radiosensitive organs during routine chest CT: Effects of tube current modulation,” Am. J. Roentgenol. 193, 1340–1345 (2009).
7. L. M. Hurwitz, T. T. Yoshizumi, P. C. Goodman, R. C. Nelson, G. Toncheva, G. B. Nguyen, C. Lowry, and C. Anderson-Evans, “Radiation dose savings for adult pulmonary embolus 64-MDCT using bismuth breast shields, lower peak kilovoltage, and automatic tube current modulation,” Am. J. Roentgenol. 192, 244–253 (2009).
8. S. Leschka, C. H. Kim, S. Baumueller, P. Stolzmann, H. Scheffel, B. Marincek, and H. Alkadhi, “Scan length adjustment of CT coronary angiography using the calcium scoring scan: Effect on radiation dose,” Am. J. Roentgenol. 194, W272–W277 (2010).
9. G. L. Raff, K. M. Chinnaiyan, D. A. Share, T. Y. Goraya, E. A. Kazerooni, M. Moscucci, R. E. Gentry, and A. Abidov, “Radiation dose from cardiac computed tomography before and after implementation of radiation dose-reduction techniques,” JAMA, J. Am. Med. Assoc. 301, 2340–2348 (2009).
10. C. McCollough, D. Cody, S. Edyvean, R. Geise, B. Gould, N. Keat, W. Huda, P. Judy, W. Kalender, and M. McNitt-Gray, “The measurement, reporting, and management of radiation dose in CT,” AAPM TG 23 Report No. 96, 2008.
11. E. J. Halpern, K. M. Takakuwa, E. L. Gingold, and D. J. Halpern, “A novel approach to reduce breast radiation exposure with coronary CTA: Angled axial image acquisition,” Acad. Radiol. 16, 951–956 (2009).
12. J. Geleijns, M. S. Artells, W. J. H. Veldkamp, M. L. Tortosa, and A. C. Cantera, “Quantitative assessment of selective in-plane shielding of tissues in computed tomography through evaluation of absorbed dose and image quality,” Eur. Radiol. 16, 2334–2340 (2006).
13. C. Hohl, J. E. Wildberger, C. Suss, C. Thomas, G. Muhlenbruch, T. Schmidt, D. Honnef, R. W. Gunther, and A. H. Mahnken, “Radiation dose reduction to breast and thyroid during MDCT: Effectiveness of an in-plane bismuth shield,” Acta Radiol. 47, 562–567 (2006).
14. K. D. Hopper, S. H. King, M. E. Lobell, T. R. TenHave, and J. S. Weaver, “The breast: In-plane x-ray protection during diagnostic thoracic CT–shielding with bismuth radioprotective garments,” Radiology 205, 853–858 (1997).
15. J. Wang, X. Duan, J. A. Christner, S. Leng, L. Yu, and C. H. McCollough, “Radiation dose reduction to the breast in thoracic CT: Comparison of bismuth shielding, organ-based tube current modulation, and use of a globally decreased tube current,” Med. Phys. 38, 6084–6092 (2011).
16. S. Vollmar and W. Kalender, “Reduction of dose to the female breast in thoracic CT: A comparison of standard-protocol, bismuth-shielded, partial and tube-current-modulated CT examinations,” Eur. Radiol. 18, 1674–1682 (2008).
18. K. Cranley, B. Gilmore, G. Fogarty, and L. Desponds, “IPEM Report 78: Catalogue of diagnostic x-ray spectra and other data,” CD-Rom edition, 1997.
19. S. E. McKenney, A. Nosratieh, D. Gelskey, K. Yang, S.-Y. Huang, L. Chen, and J. M. Boone, “Experimental validation of a method characterizing bow tie filters in CT scanners using a real-time dose probe,” Med. Phys. 38, 1406–1415 (2011).
20. S. Agostinelli, J. Allison, K. Amako, J. Apostolakis, H. Araujo, P. Arce, M. Asai, D. Axen, S. Banerjee, and G. Barrand, “GEANT4—A simulation toolkit,” Nucl. Instrum. Methods Phys. Res. A 506, 250–303 (2003).
21. ICRP, “Adult Reference Computational Phantoms. ICRP Publication 110,” Ann. ICRP 39 (2009).
22. D. Zhang, A. S. Savandi, J. J. Demarco, C. H. Cagnon, E. Angel, A. C. Turner, D. D. Cody, D. M. Stevens, A. N. Primak, and C. H. McCollough, “Variability of surface and center position radiation dose in MDCT: Monte Carlo simulations using CTDI and anthropomorphic phantoms,” Med. Phys. 36, 1025–1038 (2009).
23. S. J. Foley, M. F. McEntee, S. Achenbach, P. C. Brennan, L. S. Rainford, and J. D. Dodd, “Breast surface radiation dose during coronary CT angiography: Reduction by breast displacement and lead shielding,” Am. J. Roentgenol. 197, 367–373 (2011).
Article metrics loading...
This study investigated the effects of tilted-gantry acquisition on image noise and glandular breast dose in females during cardiac computed tomography (CT) scans. Reducing the dose to glandular breast tissue is important due to its high radiosensitivity and limited diagnostic significance in cardiac CT scans.
Tilted-gantry acquisition was investigated through computer simulations and experimental measurements. Upon IRB approval, eight voxelized phantoms were constructed from previously acquired cardiac CT datasets. Monte Carlo simulations quantified the dose deposited in glandular breast tissue over a range of tilt angles. The effects of tilted-gantry acquisition on breast dose were measured on a clinical CT scanner (CT750HD, GE Healthcare) using an anthropomorphic phantom with MOSFET dosimeters in the breast regions. In both simulations and experiments, scans were performed at gantry tilt angles of 0°–30°, in 5° increments. The percent change in breast dose was calculated relative to the nontilted scan for all tilt angles. The percent change in noise standard deviation due to gantry tilt was calculated in all reconstructed simulated and experimental images.
Tilting the gantry reduced the breast dose in all simulated and experimental phantoms, with generally greater dose reduction at increased gantry tilts. For example, at 30° gantry tilt, the dosimeters located in the superior, middle, and inferior breast regions measured dose reductions of 74%, 61%, and 9%, respectively. The simulations estimated 0%–30% total breast dose reduction across the eight phantoms and range of tilt angles. However, tilted-gantry acquisition also increased the noise standard deviation in the simulated phantoms by 2%–50% due to increased pathlength through the iodine-filled heart. The experimental phantom, which did not contain iodine in the blood, demonstrated decreased breast dose and decreased noise at all gantry tilt angles.
Tilting the gantry reduced the dose to the breast, while also increasing noise standard deviation. Overall, the noise increase outweighed the dose reduction for the eight voxelized phantoms, suggesting that tilted gantry acquisition may not be beneficial for reducing breast dose while maintaining image quality.
Full text loading...
Most read this month