Keywords:
Neuroradiology brain, Radioprotection / Radiation dose, Fluoroscopy, Radiation safety, Quality assurance
Authors:
R. M. Sanchez, E. Vano, J. M. Fernández Soto, L. Lopez-Ibor, M. M. Moreu, S. Rosati; Madrid/ES
DOI:
10.26044/ecr2019/C-2342
Methods and materials
The skin dose optimization system is applied in the neuroradiology department at the Hospital Clínico San Carlos (Madrid,
Spain).
It consists of one biplane C-arm model Allura Xper (Philips Health Care) connected to a homemade dose management system called “DOLQA” that receives,
processes and records the dose information reports sent by the modality as DICOM Radiation Dose Structured Reports (RDSR) [12].
The RDSR contain relevant information for skin dose calculation at event level,
among which generator settings (kV,
mA,
ms),
kerma at patient entrance reference point (KPERP),
kerma area product (KAP),
C-arm angulation,
beam size,
etc.
But,
in most modern C-arms,
neither the peak skin dose nor the dose distribution on patients’ skin is included in the RDSR.
The dose manager system DOLQA is linked to the prototype for skin dose calculating DIDo (Dicom Dose) in order to estimate,
to user request,
the dose distribution and the peak skin dose for one or several interventional procedures on the same patient.
Past versions of this system estimated the PSD in a reference plane [13],
but the new version currently estimates it in an anthropomorphic phantom.
The phantom size can be selected from a set of models,
depending on patient age and gender.
So as to obtain an accurate estimation of the PSD,
DIDo considers many corrections such as the attenuation from couch and mattress (10-40% depending on beam quality and C-arm angle),
the correction for the dose values provided by the modality (10% in this X-ray system),
the backscatter factor (20-40% depending on beam quality and beam size),
that are all essential to get a reliable estimation of the PSD.
Figure 1 shows an example of dose distribution estimated by DIDo.
Any patient with high dose indicators [3] is submitted to the DIDo calculation and the dose distribution and peak skin dose are given to the neuro-interventionalists to consider the clinical follow-up of potential skin lesions or/and planning future interventions.
Three clinical cases of patients with arteriovenous malformations (AVM) who needed more than one intervention are presented.