Keywords:
Quality assurance, Technical aspects, Radiation safety, CT, Radiation physics, Radioprotection / Radiation dose, Thorax
Authors:
M. González Vázquez, G. Tardáguila, C. Fraga Piñeiro, N. Silva Priegue, A. Grande, C. Trinidad; Vigo/ES
DOI:
10.1594/ecr2013/C-1679
Methods and Materials
INTRODUCTION:
Radiation dose in CT generates increasing concern.
Breast is always included in thoracic CT studies,
but never it is the organ of interest.
Technological development seeks to reduce doses from different strategies:
- Studies of high pitch: Flash (cardiac imaging)
- Selective modulation system stube:X-care decrease radiation dose ≤40% sensitive organs (breast,
thyroid...)
*Flash:Fig. 1
Flash is a prospective acquisition using 2 tubes interleaved fashion working with the same KV.
Lets to use a high pitch,
but it has a limited FOV.
*X-care: Fig. 2 ,Fig. 3
X-CARE reduces or completely switches off tube current during rotation phase in which the concerned anatomical regions are most directly exposed to radiation.
This software works to turn off x-ray tube output 120° above patient,
with a compensation of increased tube output on the posterior side of patient.
*Conventional CT: Fig. 4
Unlike X-care,
in conventional CT tube current is the same in the anterior and posterior side of patient (360º).
We analyzed 30 female patients of an outpatient basis and they are distributed at random in three groups (X-care,
Flash and conventional CT).
They are divided into 10 patients in each group and we take into account each patient's BMI ( Body mass index).
We use dual source MDCT ( Somatom Definition Flash,
Siemens) with 128 detectors.
Calculate total radiation dose as follows:
- Estimated radiation dose = dose length product (DLP) x conversion factor (0,0014)
The image quality is evaluated according to the scale:
- 1: very good quality
- 2: good quality
- 3: acceptable quality
The results were compared using Student's test statistical analysis.