Photothermographic material
View Patent ↗The invention provides a photothermographic material having, on both sides of a support, an image forming layer including at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent, and a binder, which is to be exposed with X-rays using a fluorescent intensifying screen, wherein (1) a coating amount of the photosensitive silver halide per one side is from 0.01 g/m 2 to 0.45 g/m 2 in terms of silver amount; and (2) a crossover (%) is 30% or more, or when parallel light having the same wavelength as a main emission peak wavelength of the fluorescent intensifying screen is incident perpendicular to the surface of the photothermographic material, the parallel light component of transmitted light comprises 5% or more of the incident light. A photothermographic material for medical use having high sensitivity and high image quality is provided.
1. A photothermographic material comprising, on both sides of a support, an image forming layer comprising at least a photosensitive silver halide, a non-photosensitive organic silver salt, a reducing agent, and a binder, which is to be exposed with X-rays using a fluorescent intensifying screen, wherein
(1) a coating amount of the photosensitive silver halide per one side is from 0.01 g/m 2 to 0.45 g/m 2 in terms of silver amount, and
(2) a crossover (%) is 30% or more.
2. The photothermographic material according to claim 1 , wherein the coating amount of the photosensitive silver halide per one side is from 0.02 g/m 2 to 0.4 g/m 2 in terms of silver amount.
3. The photothermographic material according to claim 2 , wherein the coating amount of the photosensitive silver halide per one side is from 0.05 g/m 2 to 0.25 g/m 2 in terms of silver amount.
4. The photothermographic material according to claim 1 , wherein the photosensitive silver halide comprises tabular grains having a mean aspect ratio of from 2 to 100.
5. The photothermographic material according to claim 4 , wherein the mean aspect ratio of the tabular grains are from 5 to 50.
6. The photothermographic material according to claim 4 , wherein the photosensitive silver halide comprises tabular grains having a mean grain thickness of from 0.001 μm to 0.3 μm.
7. The photothermographic material according to claim 4 , wherein the photosensitive silver halide comprises tabular grains having a mean equivalent spherical diameter of from 0.1 μm to 10 μm.
8. The photothermographic material according to claim 1 , wherein an exposure value necessary for obtaining an image density of fog+0.5 after exposing the photothermographic material with monochromatic light having the same wavelength as the main emission peak wavelength of the fluorescent intensifying screen and having a half width of 15 nm±5 nm and thermally developing the photothermographic material is from 1×10 −6 watt·sec·m −2 to 1×10 −3 watt·sec·m −2 .
9. The photothermographic material according to claim 1 , wherein haze of the photothermographic material after thermal development is less than 80% of that before thermal development.
10. The photothermographic material according to claim 1 , wherein the photosensitive silver halide has an average silver iodide content of 40 mol % or higher.
11. The photothermographic material according to claim 10 , wherein the photosensitive silver halide has an average silver iodide content of 80 mol % or higher.
12. The photothermographic material according to claim 11 , wherein the photosensitive silver halide has an average silver iodide content of 90 mol % or higher.
13. The photothermographic material according to claim 1 , wherein the fluorescent intensifying screen contains a fluorescent substance, and 50% or more of emission light of the fluorescent substance has a wavelength of from 350 nm to 420 nm.
14. The photothermographic material according to claim 13 , wherein the fluorescent substance comprises a divalent Eu-activated fluorescent substance.
15. The photothermographic material according to claim 14 , wherein the fluorescent substance comprises a divalent Eu-activated barium halide fluorescent substance.
16. The photothermographic material according to claim 1 , further comprising a nucleator, wherein an average gradient of a photographic characteristic curve is from 1.8 to 4.3.
17. The photothermographic material according to claim 16 , wherein the nucleator is a compound selected from the group consisting of a hydrazine derivative, a vinyl compound, and a quaternary onium compound.