Bulletin of Faculty of Health Sciences Okayama University Medical School
Published by Faculty of Health Sciences Okayama University Medical School

<Formerly known as>
岡山大学医療技術短期大学部紀要 (1巻-9巻)

Improvement of image quality on mammographic screen-film system by extended-cycle process

後藤 佐知子 岡山大学医学部保健学科放射線技術科学専攻
丸山 敏則 岡山大学医学部保健学科放射線技術科学専攻
東 義晴 岡山大学医学部保健学科放射線技術科学専攻
中桐 義忠 岡山大学医学部保健学科放射線技術科学専攻
竹田 芳弘 岡山大学医学部保健学科放射線技術科学専攻
杉田 勝彦 岡山大学医学部保健学科放射線技術科学専攻
木村 文江 岡山大学医学部附属病院中央放射線部
門久 繁文 岡山大学医学部附属病院中央放射線部
Extended-cycle process is the term used for a processor in which the processing time has been prolonged usually to approximate 210 seconds. It has been known that the extended-cycle process of some single-emulsion films as used for mammography may enhance film contrast and increase film speed. So the speed was increased in lower speed and higher resolution system than conventional systems by means of using the extended-cycle process in this paper. We investigated how much the resolution of the system was kept. A single screen-single emulsion combination, Konica M-100/CM-H was employed as a low speed and high resolution system. This film after exposure was processed in the different combinations of developing temperatures, 30, 32 and 34℃, and processing time of 210 seconds. On the other hand, Konica M-200/CM-H was employed as a high speed system. This film was processed in the standard-cycle processing (34℃, 90 seconds). Those systems were compared on contrast, speed, screen-film blur and noise by a characteristic curve, MTF (modulation transfer function) and WS (wiener spectrum). Furthermore, the RMI 165 phantom was used to evaluate visibility of mammographic details of these systems. As a result, in the extended-cycle process at the developing temperatures of 32 or 34°C and processing time of 210 seconds for M-100/CM-H, it was possible to increase the speed as much as the higher speed system, M-200/CM-H. Then the contrast, the MTF and the visibility were also improved as compared to the higher speed system. Furthermore patient dose could be reduced at the developing temperature of 34℃ and processing time of 210 seconds in M-100/CM-H.
image quality
single screen-single emulsion film system
high-resolution screen
extended-cycle process