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Should Low-Kilovoltage Chest CT Protocols Be the Rule for Pediatric Patients?

2004; American Roentgen Ray Society; Volume: 183; Issue: 4 Linguagem: Inglês

10.2214/ajr.183.4.1831172

1546-3141

Jean‐François Paul, Hicham T. Abada, Anne Sigal-Cinqualbre,

Ultrasound in Clinical Applications

AJR:183, October 2004 Should Low-Kilovoltage Chest CT Protocols Be the Rule for Pediatric Patients? We read with great interest the article by Lee at al. [1] in the March issue of the American Journal of Roentgenology describing the usefulness of MDCT in detecting aortic anomalies in children and young adults. To achieve a low-radiation-dose CT protocol, Lee et al. used 80 kV in pediatric patients weighing less than 50 kg with concomitant adjustment of the milliampere-second setting (mAs) based on the weight of the patient. In a recent paper, we showed that 80 kV was an acceptable setting for chest CT in adults weighing less than 75 kg, without substantial impairment in image quality [2]. In pediatric patients, we routinely perform chest CT examinations (> 100 examinations a year) at 80 kV (maximum, 100 mAs), on a Siemens 16MDCT scanner using submillimetric collimation. These data indicate that pediatric chest CT could be performed routinely at low kilovoltage according to the ALARA (as low as reasonably achievable) principle [3]. At a constant tube current, decreasing the kilovoltage from 120 to 80 kV results in a 56% reduction in radiation dose. Additional benefits of 80 kV include higher vascular contrast and an IV contrast medium reduction up to 50% because of the higher attenuation of iodine at 80 kV [2]. However, individual optimization of parameters (kilovoltage and milliampere-seconds) remains challenging in pediatric patients, and much remains to be done. In the protocol indicated by Lee et al. [1], for example, there is a radiation-dose increase of 225% between a pediatric patient weighing 49 kg (80 kV, 100 mAs) and one weighing 51 kg (120 kV, 100 mAs). Such an increase in the radiation dose is not justified, in our experience, to keep a constant image quality. A decrease in tube current is to be considered when increasing the kilovoltage to avoid a step effect. New intermediate settings (100 kV) provided recently on new equipment are welcome for the fine adaptation of individual radiation parameters. We again thank Lee et al. for the efforts made to reduce radiation dose in pediatric patients, which represents a challenge in our clinical practice. We are convinced that 80 kV should become the rule for chest CT in pediatric patients. Jean-Francois Paul Hopital Marie-Lannelongue Le Plessis-Robinson 92350, France Hicham T. Abada Hopital Rene Dubos Cergy-Pontoise 95303, France Anne Sigal-Cinqualbre Hopital Marie-Lannelongue Le Plessis-Robinson 92350, France