Radiation Dose to an Internal Component
Publication: Publication Date: 31 December 2015Testing Method:
The advent of digital radiography and high-speed cone beam computed tomography for routine nondestructive testing has revolutionized industrial inspection and quality assurance programs over the past decade. While exposure time for a single digital radiography image is typically much less than that required to obtain a comparable film-screen image, the large number of sequential digital radiography images generated during today’s digital radiography and computed tomography inspections can result in significantly higher overall radiation dosage as compared to when film screen was the standard radiographic technique. Knowing the internal dose received by both the digital X-ray panel and the individual internal components in a part under inspection can help avoid unexpected damage and assist in performing failure analysis. This paper reviews the source-to-surface technique to manually calculate radiation dose at an internal interface for source energies in the megaelectronvolt range, typical of those encountered when testing larger industrial objects, and provides examples demonstrating the calculation of the various parameters required. A future paper will discuss required modifications for applications in the kilovolt range.
- BJR, “Central Axis Depth Dose Data for Use in Radiotherapy,” British Journal of Radiology, BJR Supplement 17, 1983.
- Das, I.J., “Study of Dose Perturbation at Bone-tissue Interfaces in Megavoltage Photon Beam Therapy,” Ph.D. dissertation, University of Minnesota, Minneapolis, Minnesota, 1988.
- Garth, J.C., E.A. Burke, and S.W. Woolf, “The Role of Scattered Radiation in the Dosimetry of Small Device Structures,” IEEE Transactions on Nuclear Science, Vol. 27, No. 6, 1980, pp. 1459–1464.
- Garth, J.C., “High Extension of Semi-empirical Model for Energy Deposition at Interfaces,” IEEE Transactions on Nuclear Science, Vol. 28, No. 6, 1981, pp. 4145–4151.
- Garth, J.C., W.L. Chadsey, and R.L. Shepard, “Monte Carlo Analysis of Dose Profiles Near Photon Irradiation Material Interfaces,” IEEE Transactions on Nuclear Science, Vol. 22, No. 6, 1975, pp. 2562–2567.
- Gerbi, B.J., “A Mathematical Expression for %dd Accurate from Co-60 to 24 MV,” Medical Physics, Vol. 18, No. 4, 1991, p. 724.
- Hubbell, J.H., and S.M. Seltzer, “Tables of X-ray Mass Attenuation Coefficients and Mass Energy-absorption Coefficients from 1 keV to 20 MeV for Elements Z = 1 to 92 and 48 Additional Substances of Dosimetric Interest,” NISTIR 5632, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, 2004.
- Khan, F.M., and J.P. Gibbons, The Physics of Radiation Therapy, fifth ed., Wolters Kluwer Health, Riverwood, Illinois, 2014.
- Mayles, P., A. Nahum, and J.-C. Rosenwald, Handbook of Radiotherapy Physics: Theory and Practice, Taylor & Francis, New York, New York, 2007.
- Metcalfe, P., T. Kron, and P. Hoban, The Physics of Radiotherapy X-rays from Linear Accelerators, Medical Physics Publishing, Madison, Wisconsin, 1997.
- Papanikolau, N., J.J. Battista, A.L. Boyer, C. Kappas, E. Klein, T.R. Mackie, M. Sharpe, and J. Van Dyk, “Tissue Inhomogeneity Corrections for Megavoltage Photon Beams,” AAPM Report 85, American Association of Physicists in Medicine, August 2004.
- Reft, C., R. Alecu, I.J. Das, B.J. Gerbi, P. Keall, E. Lief, B.J. Mjnheer, N. Papanikolaou, C. Sibata, and J. Van Dyk, “Dosimetric Considerations for Patients with HIP Prostheses Undergoing Pelvic Irradiation,” Medical Physics, Vol. 30, No. 6, 2003, pp. 1162–1182.
- Spirydovich, S., “Evaluation of Dose Distribution for Targets Near Inhomogeneities in Photon Beam Radiation Therapy,” Ph.D. dissertation, Purdue University, West Lafayette, Indiana, 2006.
181 Page Views
0 PDF Downloads
0 Facebook Shares