RESUMEN
Personnel dose in diagnostic radiology is often underestimated. Typically the effective dose E is estimated based on dosimeters worn underneath the protective clothing measuring the personal dose equivalent Hp(10). This one-spot-measurement systematically neglects the exposure to the unshielded organs in the head and neck region. In this paper, energy dependent double dosimetry algorithms in the range of 30-80 keV are derived using organ dose conversion coefficients. The doses of shielded organs are assigned to a single dosimeter in the anterior thoracic region (chest) underneath the apron (Hp,c,u), and the doses of the organs not shielded are assigned to another dosimeter placed on the front area of the neck over the protective garment (Hp,n,o) with E = a1 Hp,c,u(10) + a2 Hp,n,o(10). Organs not completely shielded are categorized correspondingly. The coefficients a1 and a2 increase with higher energies up to 70 keV. The factors a2 are clearly higher according to ICRP 103 (rather than ICRP 60) because ICRP 103 considers additional organs in the head and neck region. According to ICRP 103, a conservative general algorithm with thyroid protection is E = 0.84 Hp,c,u(10) + 0.051 Hp,n,o(10) and without thyroid protection E = 0.79 Hp,c,u(10) + 0.100 Hp,n,o(10).
Asunto(s)
Algoritmos , Enfermedades Profesionales/prevención & control , Dosis de Radiación , Traumatismos por Radiación/prevención & control , Protección Radiológica/métodos , Radiometría/métodos , Carga Corporal (Radioterapia) , Cabeza/efectos de la radiación , Humanos , Cuello/efectos de la radiación , Ropa de Protección , Tórax/efectos de la radiación , Enfermedades de la Tiroides/prevención & control , Glándula Tiroides/efectos de la radiaciónRESUMEN
Optimization of radiation protection devices for the operator is achieved by minimizing the effective dose (E) on the basis of the recommendations of Publications 60 and 103 of the International Commission on Radiological Protection (ICRP). Radiation exposure dosimetry was performed with thermoluminescence dosimeters using one Alderson phantom in the patient position and a second one in the typical position of the operator. Various types of protective clothing as well as fixed leaded shieldings (table mounted shielding and overhead suspended shields) were considered calculating E. Shielding factors for protective equipment can readily be misinterpreted referring to the reduction of the effective dose because fixed protective barriers as well as radiation protection clothing are shielding only parts of the body. With the ICRP 103 approach relative to the exposure without lead protection, a lead apron of 0.35 or 0.5 mm thickness reduces E to 14.4 or 12.3%, respectively; by using an additional thyroid collar, these values are reduced to 9.7 or 7.5%. A thyroid collar reduces the effective dose by more than an increase of the lead equivalency of the existing apron. Wearing an apron of 0.5 mm lead-equivalent with a thyroid collar and using an additional side shield, E decreases to 6.8%. Using both a fixed side and face shield decreases E to 2.0%. For protective garments including thyroid protection, the values of the effective dose in cardiac catheterization are 47-106% higher with ICRP 103 than with ICRP 60 recommendations. This is essentially caused by the introduction of new factors for organs in the head and neck region in ICRP 103.
Asunto(s)
Cateterismo Cardíaco , Cara , Cabeza , Modelos Biológicos , Dosis de Radiación , Protección Radiológica/instrumentación , Radiometría/métodos , Efectividad Biológica Relativa , Simulación por Computador , Humanos , Traumatismos por Radiación/prevención & control , Protección Radiológica/métodosRESUMEN
Systematic gender-specific differences in anatomy and physiology are mostly neglected in standard methodologies for the determination of effective doses. This paper presents and discusses three different concepts for the derivation of gender-specific effective doses. Based on the most convincing approach--especially through the influence of tissue weighting factors for the breast--the effective dose for a serial CT scan of the chest is higher for women (+11%) and lower (-11%) for men in comparison to the "gender-neutral" average value. These differences amount to +/- 30% for coronary serial CT applications.
Asunto(s)
Radiografía Torácica/métodos , Tomografía Computarizada por Rayos X/métodos , Femenino , Alemania , Humanos , Masculino , Dosis de Radiación , Monitoreo de Radiación/métodos , Monitoreo de Radiación/normas , Radiografía Torácica/normas , Radiografía Torácica/estadística & datos numéricos , Caracteres Sexuales , Tomografía Computarizada por Rayos X/normas , Tomografía Computarizada por Rayos X/estadística & datos numéricosRESUMEN
Radiation exposure in personnel of cardiac catheterization units is based on local dosimetry during patient investigations. In the present study, dose rates were measured at various heights in representative locations, with and without fixed radiation protection shields in place. To determine the effective dose values, TLD measurements were performed using on Alderson phantom to generate radiation scatter and a second phantom in the position of the cardiologist performing the catheterization. Various types of personal radiation protection garment and fixed shields were considered in the calculations. Our results indicate on one hand that good protective standards can be achieved with effective doses below 1 mSv/year under optimized conditions. On the other hand, inappropriate radiation protection equipment can cause substantial increase of radiation doses. Alone the lack of a thyroid shield increases the effective dose of the cardiologist by a factor of 3. For the personnel, effective doses were generally higher than personal doses by a factor between 1.5 and 4.8 depending on the radiation protection situation.