Biomedical subjects

Petros N Maniatis

Publications and source records attributed to Petros N Maniatis.

3 recordsLinked to original sources

PubMed2006

Dose reduction in CT while maintaining diagnostic confidence: diagnostic reference levels at routine head, chest, and abdominal CT--IAEA-coordinated research project.

PURPOSE: To measure radiation doses for computed tomography (CT) of the head, chest, and abdomen and compare them with the diagnostic reference levels, as part of the International Atomic Energy Agency Research coordination project. MATERIALS AND METHODS: The local ethics committees of all participating institutions approved the study protocol. Written informed consent was obtained from all patients. All scanners were helical single-section or multi-detector row CT systems. Six hundred thirty-three patients undergoing head (n = 97), chest (n = 243), or abdominal (n = 293) CT were included. Collected data included patient height, weight, sex, and age; tube voltage and tube current-time product settings; pitch; section thickness; number of sections; weighted or volumetric CT dose index; and dose-length product (DLP). The effective dose was also estimated and served as collective dose estimation data. RESULTS: Mean volumetric CT dose index and DLP values were below the European diagnostic reference levels: 39 mGy and 544 mGy . cm, respectively, at head CT; 9.3 mGy and 348 mGy . cm, respectively, at chest CT; and 10.4 mGy and 549 mGy . cm, respectively, at abdominal CT. Estimated effective doses were 1.2, 5.9, and 8.2 mSv, respectively. CONCLUSION: Comparison of CT results with diagnostic reference levels revealed the need for revisions, partly because the newer scanners have improved technology that facilitates lower patient doses.

Female↗

PubMed2006

Patient doses from noncardiac diagnostic and therapeutic interventional procedures.

PURPOSE: To determine the patient doses during noncardiac diagnostic and therapeutic interventional procedures carried out in a dedicated angiographic unit. MATERIALS AND METHODS: For 1,214 interventional procedures, the technique type, dose-area product (DAP), cumulative dose (CD), and fluoroscopy time were recorded. These procedures were classified into 23 categories (10 diagnostic and 13 therapeutic) that included nine to 259 patients each. For each category, descriptive statistical analysis was used to determine the characteristics of DAP, CD, and fluoroscopy time distributions. The statistical significance of the differences observed between categories in terms of DAP was assessed. RESULTS: For the 23 categories studied, the median DAP values ranged from 0.2 to 176.8 Gycm(2). In comparison with the literature, the mean and median DAP values in this study were within reported ranges for eight categories, greater for three, and less for six, whereas for the remaining six categories no relevant data were found in the literature. CONCLUSIONS: Overall, the results of this survey indicate that the techniques used by the interventionalists, the operation skills of radiation technologists, and the performance of the x-ray unit present no obvious deficiencies in terms of patient radiation protection. However, for those procedures in which lower DAP values were found in the literature, it should be further investigated whether patient doses could be reduced without degradation of the diagnostic and therapeutic outcomes.

Analysis of Variance↗

PubMed2005

Radiation doses to patients and cardiologists from permanent cardiac pacemaker implantation procedures.

BACKGROUND: The purpose of this study was to determine the patient and cardiologist doses during the implantation of permanent cardiac pacemakers under fluoroscopic control. METHODS: For 55 procedures concerning three different types of pacemakers (DDD, VDD, and VVI), the dose-area product (DAP) meter readings and fluoroscopy times were recorded. From these data, the dose to the operating cardiologist was estimated. RESULTS: The median values of DAP and fluoroscopy time for all the procedures monitored were 11.4 Gycm(2) and 6.6 minute, respectively. For the 22 DDD, 21 VDD, and 12 VVI pacemakers implanted, the respective DAP median values were 14.7, 9.9, and 7.3 Gycm(2) and the respective median fluoroscopy times were 8.4, 5, and 2.9 minutes. The median doses to the hands, chest, eyes, and legs of the cardiologist conducting the manipulations were estimated to 0.21, 0.06, 0.03, and 0.11 mGy, respectively, per procedure. CONCLUSIONS: Compared to the existing literature, the median DAP value of this study is almost identical to the 11.2 Gycm(2) reported from a sample of 627 patients in 17 different x-ray rooms, whereas the fluoroscopy times are within the range of values reported by other authors. Concerning the cardiologist exposure, the estimated values indicate that the implantation of pacemakers is a procedure that does not involve a severe risk, especially if it is taken into account that lead aprons and collars are routinely used.

Analysis of Variance↗