Radiodiagnostico lif: ct

http://rpd.oxfordjournals.org/content/early/2010/11/25/rpd.ncq418.full

PRELIMINARY ASSESSMENT OF THE DOSE TO THE INTERVENTIONAL RADIOLOGIST IN FLUORO-CT-GUIDED PROCEDURES

1. M. F. Pereira1,*,
2. J. G. Alves1,
3. S. Sarmento2,3,
4. J. A. M. Santos2,3,
5. M. J. Sousa4,
6. M. Gouvêa5,
7. A. D. Oliveira1,
8. J. V. Cardoso1 and
9. L. M. Santos1
+ Author Affiliations1. 1Instituto Tecnológico e Nuclear (ITN),Unidade de Protecção e Segurança Radiológica (UPSR), EN10, 2686-953 Sacavém, Portugal
2. 2Instituto Português de Oncologia do Porto de Francisco Gentil E.P.E. (IPOPFG E.P.E.), Centro de Investigação, Rua Dr. A. Bernardino de Almeida, 4200-072 Porto, Portugal
3. 3IPOPFG E.P.E., Serviço de Física Médica, Porto, Portugal
4.4IPOPFG E.P.E., Serviço de Radiologia de Intervenção, Porto, Portugal
5. 5IPOPFG E.P.E., Serviço de Radiologia, Porto, Portugal
1. *Corresponding author: mnfpereira@itn.pt
 
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Abstract
A preliminary assessment of the occupational dose to the intervention radiologist received in fluoroscopy computerised tomography (CT) used to guide the collection of lung and bone biopsiesis presented. The main aim of this work was to evaluate the capability of the reading system as well as of the available whole-body (WB) and extremity dosemeters used in routine monthly monitoring periods to measure per procedure dose values. The intervention radiologist was allocated 10 WB detectors (LiF:Mg, Ti, TLD-100) placed at chest and abdomen levels above and below the lead apron, and atboth right and left arms, knees and feet. A special glove was developed with casings for the insertion of 11 extremity detectors (LiF:Mg, Cu, P, TLD-100H) for the identification of the most highly exposed fingers. The Hp(10) dose values received above the lead apron (ranged 0.20–0.02 mSv) depend mainly on the duration of the examination and on the placement of physician relative to the beam, whilevalues below the apron are relatively low. The left arm seems to receive a higher dose value. Hp(0.07) values to the hand (ranged 36.30–0.06 mSv) show that the index, middle and ring fingers are the most highly exposed. In this study, the wrist dose was negligible compared with the finger dose. These results are preliminary and further studies are needed to better characterise the dose assessmentin CT fluoroscopy.

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INTRODUCTION
Staff doses in interventional radiology procedures are generally higher than those received in other radiology practices(1). The use of personal protective devices such as lead aprons, gloves, thyroid shields and goggles is recommended, and depending on the practice this may be complemented with other devices such as screen andtable shields. As the dose distribution pattern is often unknown, the individual monitoring of staff also raises some questions like the number and correct positioning of the whole-body (WB) and of the extremity dosemeters. Vañó and Faulkner(2) recommend the use of robust and adequate monitoring arrangements for staff. The analysis of individual monitoring data generated by WB and extremitymeasurements is not easy and suggests the need of further studies, particularly for some techniques(3).

Computerised tomography (CT) is a useful imaging technique to guide biopsies and other interventional procedures such as radiofrequency ablation, benefiting from the identification of very small lesions and allowing the visualisation of the needle tip and of the critical structures along its entrypath, as well as providing evidence that the sample was collected from the place of interest(4). The CT-fluoroscopy mode(5), available commercially since 1994, is increasingly used in the more complex cases such as lung biopsies, where real time in room imaging presents a clinical advantage. During CT-fluoroscopy-guided procedures, the interventional radiologist is generally located in the...