Evaluation of Patients Doses During CT Angiogaphy

Abstract

Recent technical advancements in CT have resulted in a remarkable growth in the use of CT imaging in clinical practice. CT Angiography (CTA) has become the most useful imaging test of blood vessels; It provides noninvasive examination of the patient. Prior to the introduction of CTA conventional angiography had been considered of the best initial imaging test for evaluation of blood vessels but is to invasive for the patient. The objective of this study were to measure patient radiation dose during CTA imaging,evaluation of imaging protocol compare to the international practice, and estimation of radiation hazard for patient. The study was conducted in two Radiological departments equipped with two 64 slice CT machines (Toshiba, Aquilion ONE, Toshiba Medical Systems, Otawara, Japan 2010). Both machined passed successfully the quality control tests performed by Sudan Atomic Energy commission. A total of 32 patients were examined during three month (14 patients in Alzaitouna specialized Hospital and 18 in Al-amal national Hospital). The dose values and patient parameters was recorded using data sheet collection. The mean patient age was 55.6 in Alamal national hospital. In ALzitouna specialized hospital the mean age was 42.9 and the mean values of DLP are 2363.828 and 5221.521 respectively. In AL-amal national hospital the mean value of DLP and CTDI is 2363.8 mGy. cm – 412.98 mGy for all examinations, for CCTA 777.7 mGy. cm CTDI 216 mGy, for the brain DLP 1428.8mGy.cm CTDI 144.7 mGy, for the neck DLP 2402.7 mGy.cm CTDI 950.5 mGy , neck and head DLP2131.6 mGy.cm CTDI 559.9 mGy,neck head and chest DLP4592.7 mGy.cm CTDI 1019.4 mGy,chest DLP 405.7 mGy.cm CTDI 236.9 mGy ,abdomen DLP mGy.cm 1391.3 CTDI493.9 mGy,lower limb DLP 4501.1 mGy.cm CTDI 389 mGy. In ALzitouna specialized hospital the mean value of DLP and CTDI is 5221.5 mGy. cm –565.9 mGy for all examinations, , for the brain DLP 1186 mGy.cm CTDI 627mGy, for the neck and brain DLP 4668.2 mGy.cm CTDI 1165.3 mGy , chest DLP1453.6 mGy.cm CTDI 356.3 mGy,abdomen DLP 2235.6 mGy.cm CTDI 647.6 mGy, Kidney DLP 2120.2 mGy.cm CTDI 629.1 mGy , Upper limb DLP 3250.7mGy.cm CTDI248.6mGy,lower limb DLP 10272.6 mGy.cm CTDI 602.9mGy. The results of this study showed wide variations between the two hospitals and patients. CTA imaging protocols should be standardized for both hospitals in order to reduce the dose variation across patients and facilities. Technologists and physicians need to follow guidelines for reducing dosages. Exposure parameters must base on patient weight and anatomic region of interest. Additional radiation dose survey is essential in order to establish a local diagnostic reference level in Sudan.