Patient Dose Measurement in TACE and PTBD Procedures Using Scintillation with Optical Fiber Dosimeter

Abstract

The scintillation dosimeter is most suitable for skin dose measurement for its small size of detector, easily use and there was no need to estimate the surface area exposure. However, scintillation detector could identify the result in limited area because of the small size of detector. During the procedure to identify the selected vascular supply tumor, the CT was scanned in patients which increasing the surface dose. TransArterial ChemoEmbolization (TACE) procedure and Percutaneous Transhepatic Biliary Drainage (PTBD) are the procedures producing high dose to both patients and staff. Radiation skin injury to patient was reported by these interventional procedures. The objective of this study is to determine patient skin dose measured by the scintillation detector, MIDSOF. TACE procedure using Angiographic and CT systems, PTBD procedure using Angiographic system, manufactured by Toshiba Medical System Corporation at Interventional Radiology Unit, King Chulalongkorn Memorial Hospital, the patient skin dose was measured by MIDSOF dosimeter. The patient data, the air kerma area product (KAP) and DLP had been recorded. The equivalent dose was calculated from DLP (mGy.cm) values displayed on CT console and from KAP (Gy.cm2) displayed on fluoroscopic procedures. TACE procedure included fifty-four consecutive patients (11 female and 43 male) during the period of July 2016 to February 2017. The mean ± SD of age, height, weight and BMI were 63.3±9.9 years, 164±8.4 cm, 65.7±10.1 kg and 24.4±3.4 kg/m2 respectively. The mean ± SD of fluoroscopic time, total number of radiographic frames were 33 ± 15 min and 220 ± 194 respectively. The mean ± SD of patient skin dose was 1.71 ± 1.14 (0.023 – 5.48) Gy. The mean ± SD of patient dose determined by KAP was 379.88 ± 147.78 (59.9 – 725.2) Gycm2. The correlation, r between the air kerma area product, KAP (Gycm2) and patient skin dose determined by MIDSOF (Gy) was 0.76. The mean equivalent dose with range of fluoroscopic and CT procedures were 70.86 (15.57-188.55) and 6.93 (3.19 - 20.47) mSv respectively. PTBD procedure included eight consecutive patients (2 female and 6 male). The mean ± SD of KAP values were 21.9 ± 26.9 (1.67 – 87) Gy.cm2. The mean ± SD of the equivalent dose and range was 5.69 ±7.01 (0.43– 22.6) mSv. The mean ± SD of patient absorbed dose and range were 0.14 ± 0.21 (0.004 - 0.7) Gy. In this study, 12 patients from TACE procedure received the skin dose exceed 2 Gv for erythema and epilation at prompt and early exposures.