Radiation transfer in medical X-ray intensifying screens

Proceedings of SPIE - The International Society for Optical Engineering

Volumn 535, Issue , 1985, Pages 148-156

  Mickish, Daniel J ^a  

^a DUPONT COMPANY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

LIGHT - SCATTERING;

BINDER REFRACTIVE INDEX; MONTE CARLO METHOD; RADIATION TRANSFER; X-RAY INTENSIFYING SCREEN;

RADIOGRAPHY;

EID: 0021939450     PISSN: 0277786X     EISSN: 1996756X     Source Type: Conference Proceeding    
DOI: 10.1117/12.947249     Document Type: Conference Paper

References (15)

1. Rabatin, J. G., “Industrial Applications of Rare Earth Elements”, ACS Symp. Ser. 164, 203 (1981).
2. Bernard, R., Hamilton, J. F., and Bunch, P. C., “Fundamental Aspects of Mammographic Photoreceptors: Screens”, in Reduced Dose Mammography, Eds. W. W. Logan and E. P. Muntz, Masson Pub., New York, N. Y., 529 (1979)
3. Richards, W., “The Calculation of the Optical Performance of Paint Films”, J. Paint Tech., 42, 276 (1970).
4. Mudgett, P. S., and Richards, L. W., “Multiple Scattering Calculations for Technology I”, Applied Optics, 10, 1485 (1971).
5. Mudgett, P. S., and Richards, L. W., “Multiple Scattering Calculations for Technology II”, J. Colloid and Interface Sci. 39, 551 (1972).
6. Kortum, Reflectance Spectroscopy, Springer-Verlag, New York (1969), p. 12. Note that 1/2 should be added to correct the expression (Eq. 24) for the average diffuse internal reflectance over 2 IT steradians – used in the 4-flux calculation. Equation (16) is integrated numerically, with cosine weighting and appropriate normalization, for use in the 6-flux calculation.
7. Brown, F. C., The Physics of Solids, W. A. Benjamin, Inc., New York, (1967), p 224.
8. Swank, R. K., “Calculation of Modulation Transfer Functions of X-Ray Fluorescent Screens”, Appl. Optics, 12, 1865 (1973).
9. McKelvey, J. P., Solid State and Semiconductor Physics, Harper and Row, New York (1966), Eqs. 10.5-11,-13.
10. Wallace, P. R., “Neutron Distributions in Elementary Diffusion Theory: I”, Nucleonics, Feb., 31 (1949).
11. PROSE Computer Language, Prose, Inc., Los Angeles, CA.
12. Waring, R. K., Unpublished work: “Use of the GARY 14 Integrating Sphere for Measurement of Diffuse Transmittance and Reflectance of X-ray Intensifying Screens”, E. I. duPont CR&D Dept., Wilmington, DE 19898, Sept. 1 (1981)
13. The model screens, crystal “diameters”, and speeds were supplied by Dr. J. R. Joiner, E. I. du Pont P&EP Dept., R&D Division, Towanda, PA. 18848.
14. The computer program did not yield scattering parameters λS and which were independent. That is, ordered pairs of (λS, ), defining a line segment in a limited region of 2-dimensional space, produced equally good fits, essentially within experimental error. When fitting exact, theoretically calculated data, the program rapidly converged to the theoretical scattering parameters--suggesting that it was the 0.5% experimental error or the truncation of the scattering function that prevented determination of unique scattering parameters. A fixed value of = 0.69 was found to permit excellent convergence of the remaining parameters (less than 0.7% standard error in calculated f fluxes) for all the composites. Although this value lies within the range of the cosine function, E. B. Caruthers, E. I. du Pont CR&D, Wilmington, DE 19898, has pointed out that this value produces non-physical, negative values for the (truncated) scattering probability function. I was unable to repeat, in time for publication, the optimization process and find parameters which yielded non-negative values for the scattering function. I believe however that the main conclusions of the paper remain unaffected: the viability of the methods used and the wavelength and crystal size effects on λC and λS.
15. van de Hulst, H. C., Light Scattering by Small Particles, John Wiley, New York (1957), pp. 176-177. Note that Q ext ranges from 0 for no refractive index difference to near-maximum for very small differences.