Small dose of oral gastrografin for computed tomography-based image-guided brachytherapy in patients with uterine cervical cancer.

Oral administration of a water-soluble iodine contrast agent (gastrografin) was reported to assist in the appropriate contouring of the small intestine on computed tomography (CT)-based radiotherapy (RT) planning. The efficacy and optimal dose of gastrografin in CT-based image-guided brachytherapy (IGBT) for cervical cancer remain unknown. This study aimed to investigate the efficacy of pretreatment oral administration of gastrografin at a small dose of 50 ml in CT-based IGBT for cervical cancer. A total of 422 sessions in 137 patients who underwent CT-based IGBT with 50 ml of oral gastrografin (concentration, 3% or 4%) were analyzed. Preparation of gastrografin was judged as effective when the small intestine was contrast-enhanced at the area where the small intestine was in contact with the uterus/adnexa. About 287 out of 422 sessions (68%) were judged as effective with gastrografin preparation. The 135 ineffective sessions were considered as follows: (i) the contrast enhancement of the small intestine was not confirmed (n = 36), (ii) the small intestine was not in contact with the uterus/adnexa despite the confirmation of the contrast enhancement of the small intestine (n = 34), and (iii) gastrografin was absent in the small intestine at the area in contact with the uterus/adnexa, even when gastrografin was observed in the small intestine at the area not in contact with the uterus/adnexa (n = 65). In conclusion, pretreatment oral administration of a small dose gastrografin achieved moderate efficacy for accurate contouring of the small intestine close to the uterus/adnexa in CT-based IGBT for cervical cancer.

Three-dimensional measurement of an inner surface profile using a supercontinuum beam.

We demonstrate an inner surface profile measurement that has a smooth spatial distribution. A supercontinuum beam suppresses the speckle contrast to 22% and the standard deviation of the point cloud to 40%, compared to equivalent values obtained by use of a conventional green He-Ne laser at a wavelength of 543.5 nm. A compact probe for the inner surface profile measurements using the supercontinuum beam measures the depth removed by wear of a small hole in an automobile component. The radial spatial resolution was evaluated to be 2 µm, which was of the same order as the wavelength of the supercontinuum beam. The supercontinuum beam enables fivefold improvement of the radial spatial resolution compared to the monochromatic wavelength beam because of a reduction in speckle effects.