Learning objectives
To understand a patient’s entrance surface dose (ESD) and the dose distribution in coronary computed tomography angiography (CCTA),
which requires a high dose.
To emphasize the importance of reducing the mammary entrance surface dose for CCTA.
Background
Coronary computed tomography angiography (CCTA) is widely used for noninvasive cardiac imaging to evaluate coronary artery disease (Fig.1).
As CCTA examination delivers higher radiation doses compared to other types of computed tomography (CT) examinations,
it is crucial to manage the radiation exposure.
High radiation doses have the potential to cause deterministic effects and stochastic effects in patients.
Furthermore,
according to ICRP Publication 105,
the tissue weighting factor,
which is a relative measure of the risk of stochastic effect,
for the breast was increased from 0.05...
Findings and procedure details
Development of the actual measurement system of ESD in CCTA
We devised a direct measurement system using many arrayed radiophotoluminescence glass dosimeters (RPLDs) to accurately measure the ESD and the dose distribution map of CCTA (Fig.3).
The RPLDs were placed in 84 pockets sewn into the dosimetry gown.
RPLDs are usually equipped with energy compensation filters made of tin.
However,
compensation filters are radiopaque materials.
Thus,
we chose the GD-302M (12 mm in length and 1.5 mm in diameter) with no energy compensation filter as...
Conclusion
The evaluation of the influence of the bed height by MTF showed no difference in MTF from the CT gantry center up to 20 mm.
Raising the bed to the height of a normal CT appears to cause the reduction of the mammary surface dose in CCTA.
Personal information
Mamoru Kato,
Ph.D.
Department of Radiology and Nuclear Medicine,
Research Institute for Brain & Blood Vessels-Akita,
6-10 Senshu-Kubota Machi,
Akita,
Akita 010-0874,
Japan.
Course of Radiological Technology,
Health Sciences,
Tohoku University Graduate School of Medicine.
2-1 Seiryomachi,
Aoba,
Sendai 980-8575,
Japan.
Koichi Chida,
Ph.D.
Course of Radiological Technology,
Health Sciences,
Tohoku University Graduate School of Medicine.
2-1 Seiryomachi,
Aoba,
Sendai 980-8575,
Japan.
Takashi Moritake,
MD,
Ph.D.
Department of Radiological Health Science,
Institute of Industrial Ecological Sciences,
University of Occupational and Environmental Health,
Japan.
1-1,
Iseigaoka,...
References
1.Balter S,
Miller DL.
Patient skin reactions from interventional fluoroscopy procedures.
AJR Am J Roentgenol 2014; 202: W335–342.
2.International Commission on Radiological Protection.
ICRP publication 85: avoidance of radiation injuries from medical interventional procedures.
Ann ICRP 2001; 30/2: Publication 85.
3.Chida K,
Inaba Y,
Saito H,
et al.
Radiation dose of interventional radiology system using a flat-panel detector.
Am J Roentgenol 2009; 193:1680–1685.
4.Chida K,
Ohno T,
Kakizaki S,
et al.
Radiation dose to the pediatric cardiac catheterization and intervention patient.
Am J Roentgenol 2010;...