Human body temperature has served as one of the most fundamental vital signs for clinical diagnosis and daily healthcare. Body temperature is generated by vital reactions. Therefore, measurement of body temperature may sense signs of disease or recovery, and has been studied in several disease states or health conditions1, 2). In clinical, several minimally invasive procedures (hyperthermia therapy, radiofrequency ablation and cryotherapy etc.) for the local treatment are evolved and use of those is increasing3) (Fig. 1 and Fig. 2). In those therapy, measurement of...

1. Theoretical background of CT based thermometry CT based thermometry is obtained indirectly the temperature information from CT values of the subject. CT value is calculated from the linear attenuation coefficient of subject and water. Moreover, the linear attenuation coefficient varies with physical density and the mass attenuation coefficient for a given material. Because the physical density of a material is affected by temperature due to thermal expansion, the CT value depends on temperature. Therefore if temperature increases, thermal expansion causes the decrease of density...

Fig. 7shows the CT-Temp conversion table of the histological samples, and Fig. 8shows the first order approximation of the CT-Temp conversion table. In all samples, CT value decreased with increasing temperature (Thermal sensitivity: -0.2 to -1.3 HU/°C) between 5 and 60 °C. However, between -20 and -5 °C, liver, kidney, and muscle CT values increased with the increasing temperature (Thermal sensitivity: 0.6 to 1.4 HU/°C), but fat decreased (Thermal sensitivity: -0.6 HU/°C). At around -5 ° C, liver, kidney, and muscle containing much water showed...

Visualization to deep temperature in swine living body was possible using X-ray CT, because of look-up table with color changed at 5 °C intervals roughly reflected the temperature distribution. This study is expected to develop into a new diagnostic imaging using treatment support and the temperature information.

S. Mizukami; Sagamihara, Kanagawa/JP - nothing to disclose H. Hara; Sagamihara, Kanagawa/JP - nothing to disclose D. Hatakeyama; Sagamihara, Kanagawa/JP - nothing to disclose E. Kanai; Sagamihara, Kanagawa/JP - nothing to disclose D. Yokoyama; Sagamihara, Kanagawa/JP - nothing to disclose H. Muraishi; Sagamihara, Kanagawa/JP - nothing to disclose T. Gomi; Sagamihara, Kanagawa/JP - nothing to disclose

1).Ministry of Health, Labour and Welfare secretariat statistics and information department, social medical intervention stats. 2012-2018. https://www.e-stat.go.jp/stat-search/files?page=1&toukei=00450048&tstat=000001029602 2) KELLY, Gregory S. Body temperature variability (Part 2): masking influences of body temperature variability and a review of body temperature variability in disease. Alternative medicine review, 2007, 12.1. 3) LAWSON, Ray N.; CHUGHTAI, M. S. Breast cancer and body temperature. Canadian Medical Association Journal, 1963, 88.2: 68. 4) Arthur RM, Straube WL, Trobaugh JW, Moros EG. In vivo change in ultrasonic backscattered energy with temperature in motion-compensated...