Havukainen R, Servomaa A
Oral Surg Oral Med Oral Pathol. 1986 Jul;62(1):107-9. doi: 10.1016/0030-4220(86)90081-2.
The characteristic curves of the dental x-ray films Ultra-Speed, Ekta-Speed, Defilux, Dentus, and Phil-X30, all of which are used in Finland, and the absorption of radiation in the films with their protective wrappers were determined at the x-ray laboratory of the Institute of Radiation Protection. The most sensitive film (Ekta-Speed) was found to be almost three times more sensitive than the least sensitive film (Defilux). In the usable optical density range, the gradient of the characteristic curve obtained with the three most sensitive film types--Ekta-Speed, Dentus and Ultra-Speed--was roughly the same, whereas Phil-X30 was far more gentle. All film types gave a resolution better than 10 lp/mm. The grain size used in the most sensitive film was slightly larger than that used in the less sensitive films. The films provided with lead backing foil transmitted 10% to 20% of the radiation, whereas the film type without lead backing foil (Phil-X30) transmitted 70% to 80%.
对芬兰使用的Ultra-Speed、Ekta-Speed、Defilux、Dentus和Phil-X30牙科X光片的特性曲线以及带有防护包装的胶片的辐射吸收情况，在辐射防护研究所的X光实验室进行了测定。结果发现，最敏感的胶片（Ekta-Speed）的敏感度几乎是最不敏感的胶片（Defilux）的三倍。在可用的光学密度范围内，三种最敏感的胶片类型——Ekta-Speed、Dentus和Ultra-Speed——所获得的特性曲线的梯度大致相同，而Phil-X30则平缓得多。所有胶片类型的分辨率均优于10 lp/mm。最敏感胶片所用的颗粒尺寸略大于较不敏感胶片所用的颗粒尺寸。带有铅背衬箔的胶片能透射10%至20%的辐射，而没有铅背衬箔的胶片类型（Phil-X30）能透射70%至80%。
