[Evaluation of the number of sampling step angles in SPECT Images: comparison between FBP and OS-EM reconstruction algorithms].

We compared filtered back projection (FBP) and ordered subset expectation maximization (OS-EM) reconstruction algorithms to examine the effects of sampling step angle on SPECT image reconstruction. Image sampling was compared between conditions of constant total sampling time (16 min) and constant sampling time (40 sec) for each step with angles of 3, 5, 7.5, and 10 degrees.

[Usefulness of simulation with multi-slice CT for laparoscopic nephrectomy].

In recent years, laparoscopic surgery has attracted attention as a minimally invasive type of surgery because of the small surgical wounds and early recovery it provides. We carry out this technique on the basis of volume data that we make use of in multi-slice CT imaging technology in laparoscopic nephrectomy by the retroperitoneal approach, and we have created CT virtual laparoscopy by virtual endoscopic display as an intra-operative navigatior with an image analysis system. We provide information on detailed vascular anatomy to form intra-operative images that act as similar support images.

[Usefulness of a dose distribution analysis system with a common scanner].

Although one-dimensional densitometry has been widely performed for linac dosimetry, it is a time-consuming, labor-intensive procedure. We studied a new densitometry system (DD-System) that consists of a personal computer and common flatbed-type scanner, with regard to its usefulness for daily QC checks in comparison with conventional densitometry. The spatial resolution of the DD-System is very high, and its accuracy of measurements of field size and flatness are equivalent to those of a conventional system at an optical density <2.

Use of multidetector row CT with volume renderings in right lobe living liver transplantation.

Multidetector row CT is a feasible diagnostic tool in pre- and postoperative liver partial transplantation. We can assess vascular anatomy and liver parenchyma as well as volumetry, which provide useful information for both donor selection and surgical planning. Disorders of the vascular and biliary systems are carefully observed in recipients.