Dose reduction in subsecond multislice spiral CT examination of children by online tube current modulation

Abstract

The potential of online tube current modulation in subsecond multislice spiral CT (MSCT) examinations of children to reduce the dose without a loss in image quality is investigated in a controlled patient study. The dose can be reduced for oval patient sectional view without an increase in noise if the tube current is reduced where the patient diameter and, consequently, attenuation are small. We investigated a product version of an online control for tube current in a SOMATOM Sensation 4 (Siemens, Forchheim). We evaluated image quality, noise and dose reduction for examinations with online tube current modulation in 30 MSCT of thorax/abdomen and abdomen and compared mA s for tube current modulation to the mA s in standard weight-adapted children protocols. Image quality was rated as "very good," "good," "diagnostic" and "poor" in a consensus by three radiologists. Noise was assessed in comparison to 24 MSCT examinations without tube current modulation measured as SD in ROIs. The dose was reduced from 26 to 43% (mean 36%), depending on the patient's geometry and weight. In general, no loss of image quality was observed. Measured noise showed a decrease up to 26% and an increase up to 36%, although there was no decrease of image quality. Online tube current modulation is now used as a standard in MSCT at our institution. Dose in MSCT examinations of children can be reduced substantially in routine examinations by online tube current modulation without a loss of image quality.

Aortoiliac and Lower Extremity Arteries Assessed with 16–Detector Row CT Angiography: Prospective Comparison with Digital Subtraction Angiography

“…Reduction of radiation exposure was possible in our study through the use of an online modulation of tube current implemented with the 16 -detector row CT scanner for all 16 -detector row CT angiograms. Greess (26) demonstrated a reduction of the effective dose from 26% to 43% in children on the basis of the patient's body shape and weight by using a multi-detector row CT scanner with an attenuation-based online modulation of the tube current. For the pelvis and extremities, a mean effective dose reduction of 25% and 39%, respectively, could be obtained in another study by using a single-detector row CT scanner and attenuation-based on-line modulation of the tube current (27).…”

The effective dose result of18F-FDG PET-CT paediatric patients

“…Higher tube current will give more radiation dose to patients [4,6]. Thus, adjustment of tube current based on patient size will reduce the radiation dose to patients especially in paediatric patients [24,25]. Furthermore, other CT imaging parameters such as tube voltage, pitch, time per bed and rotation can be adjusted manually to obtain good images [22] rather than rely on AEC function only.…”

Detection of liver metastases under 2 cm: comparison of different acquisition protocols in four row multidetector-CT (MDCT)

“…As we wanted to specifically evaluate the influence of slice thickness and table speed on the detection of low contrast lesions, we used the same radiation dose for the four protocols. The CTDIw applied was adapted to the recommended dose for abdominal CT by the European Guidelines, which suggest CTDIvol values ranging from 17.5 to 29.5 mGy for liver screening investigation [17][18][19][20][21]. In addition, in a previous experimental study performed with a phantom simulating the X-ray absorption of a standard abdomen, it has been demonstrated that for the detection of 5 mm lesions to achieve a CNR of 1, which ensures a detection rate of 100%, the X-ray dose required correspond to a CTDIw=20 mGy [11].…”