U : Use factor. K p 0 : Total air kerma at the distance d P corrected by the use factor U. B P x barrier 1 : Maximum transmission allowed to the shielding so as not to exceed the maximum value of the kerma in air allowed P , corrected by the occupancy factor T. P : Air kerma limit, according to the type of adjacent area. T : Occupancy factor. K S 1 : Air kerma due to scattered radiation within one meter of the scattering source, with a determined scattering angle.
B sec x barrier 2 : Maximum transmission allowed to the shielding so as not to exceed the maximum value of the air kerma allowed P , corrected by the occupancy factor T. HTML language was chosen because it allows publishing information globally. Calculations were carried out by applying JavaScript tools. The portability to different electronic devices is guaranteed by the Bootstrap framework applied. HTML is the standard markup language for creating web pages and web applications.
HTML can embed programs written in a scripting language such as JavaScript, which affects the behavior and content of web pages. JavaScript is a high-level, interpreted programming language characterized as dynamic, weakly typed, prototype-based and multi-paradigm. It enables interactive web pages and thus is an essential part of web applications. Bootstrap is a free and open-source front-end framework for developing websites and web applications. It concerns itself with front-end development only.
Figure 1 shows a flow diagram describing the app design. References: I. Functions that make visible fields to be fulfilled in the forms basic and advanced fields , according to the barrier primary or secondary selected. It is applied to conventional X-ray and dedicated chest rooms. Function that makes visible fields to be fulfilled in both forms basic and advanced fields in order to estimate secondary barriers for mammography rooms. Function that makes visible fields to be fulfilled in both forms basic and advanced fields in order to estimate secondary barriers for CT rooms.
After the room and the barrier are selected, the user must decide if the form will be fulfilled for basic or advanced fields, taking account of the available information. Each form already has specific fields uploaded depending on the type of room and barrier under consideration.
When estimating the primary barrier thickness, the attenuation or pre-shielding produced by the image receptor is considered. Shielding thickness results are shown in a table for five different materials lead, standard concrete, gypsum, glass and solid wood.
Figure 2 shows the main screen of the application, where the user must select the type of room, and whether the type of barrier corresponds. Only one option can be selected for both cases, however once the thicknesses have been calculated, the user can return to this tab, select another room or another barrier in the same room and perform the calculations for it.
In this case, because the app assumes the workload is performed at the kilovoltage entered by the user, the results are more conservative than in the other option Figure 4.
The results will be added in the table below those calculated previously. Figure 5 shows the screenshot of the Results tab.
Figure 6 shows how the application interface adapts when used on mobile devices. In this screenshot it can be observed that, with respect to the interface for larger resolutions, the fields are kept reorganizing their distribution and size, this is the characteristic that the Bootstrap framework provides. The exercise determined thickness values for radiographic room shown in Figure 7. The application presented in this paper gives the user the possibility to perform shielding calculations.
The barrier thicknesses required to protect areas around a source of X-ray radiation can be easily computed and the effectiveness of an existing barrier can be quickly verified. The tools which the application was developed with, allow the application to be adaptable to any device that has a web browser, presenting a user-friendly interface, making its use easy and intuitive. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Main screen of the application, where the facility and type of barrier should be selected. Screenshot of the input information tab, basic fields form, conventional X-ray or dedicated chest room. Screenshot of the input information tab, advanced fields form, conventional X-ray or dedicated chest room.
Screenshot of the results tab. Related Audiobooks Free with a 30 day trial from Scribd. Empath Up! Calculating shielding requirements in diagnostic xray departments 1.
Structural radiation protection for diagnostic X-ray facilities is most commonly per- formed following the recommendations of the National Council on Radiation Protection and Measurements Report No.
A number of analytical methods have already been developed to improve the design of these facilities. Thus, they generate an overall solution for the cases met at the medical radiation structural design. This paper presents an extension of an existing method for calculating shielding requirements, for multiple X-ray tubes in a room operated at var- ious beam qualities. The methodology computes the required shielding thickness such that the exposure behind it stays below a desired value.
The presented method eliminates the overestimation of added shielding thickness which may occur using the other methods already mentioned. A user- friendly windows-based program has also been developed to assist shielding computations.
This has been proved by Archer et al [2] to be an arbitrarily conservative addition, leading the weekly exposure of personnel to be reduced more than required according to the designed maximum permissible dose MPD lim- its. Additionally, the calculation of barrier requirements include many uncertainties e. Theyhavetriedtoeliminatetheresul- tant overshielding barrier of NCRP 49 [1] and to allow greater accuracy in the computation proce- dure.
Theirapproachhasbeenextendedandgeneral- ized by McGuire [3], who illustrated methods for performing shielding calculations for multiple sources of radiation in a diagnostic room, operating atthe same tube potential kVp values.
Additionally, a user-friendlyWindows- based program has been implemented, based on the proposed method, to compute shielding require- ments of a diagnostic X-ray room. Methods and materials Theoretical background The required protective barrier thickness in a diagnostic X-ray room can be calculated comple- tely from a single equation proposed by McGuire [3].
The method requires that the weekly exposure radiation levels from primary, scatter and leakage radiation emitted from each X-ray source in the Received 13 November and in revised form 7 August , accepted 24 August Address correspondence to George Panayiotakis.
This work has been supported by the Greek Ministry of Health K. The i sources of radiation exposure include primary, scatter and leakage radiation from all the X-ray tubes in the room. The radiation type j concerns the maximum operating potential of the X-ray source and does not vary in the above equation, providing the constraint that all the X- ray tubes in the room operate at the same maxi- mum tube potential kVp values.
Tij x represents the transmission characteristics of source i, radia- tion type j, through the barrier material of thick- ness x. K characterizes attenuation of X-rays for a certain material. The above method has the advantage of approaching the problem of additional shielding calculation, when structural shielding already exists, providing an estimate for a material 1 of thickness x1 necessary to be added in front of a barrier, constructed from a material 2 of known thickness x2, so as to satisfy the shielding requirements.
However, the appropriate material thickness for a beam to be hardened cannot be exactly known and the method leads to an overestimation of added material, as will be shown in the results section. Consider a single radiation source emitting pri- mary, scatter and leakage radiation. Since the unshielded weekly exposures PP, PS and PL in the area to be protected are known, one can calculate, using Equation 5 , the thickness of material x needed to reduce the total weekly exposure to MPD.
Referring to Figure 2, suppose that x1 is the thickness of mate- rial 1 required to be placed in front of an existing Figure 1. Qualitative representation of the transmis- sion of primary and scatter radiation through two adja- cent slabs of the same material with thickness x1 and x2.
Figure 2. The same trans- mission of the X-ray beam through thickness x1 can be obtained by a thickness x3 of material 2.
The same transmission of the X-ray beam through thickness x1 of material 1 corresponds to a thickness x3 of another material 2. Using this equation, the additional protective barrier thickness x1 required to set PT to MPD can be calculated.
Implementation The described method has been developed in Microsoft Visual Basic 4. The values of Kuxj x and Koj for tube voltages of 50, 70, , and kVp and for lead, gypsum, steel and plate glass constructed materials, have been calculated with the use of Archer et al's mathematical model [2]. For this calculation the experimental determina- tion of three parameters alpha, beta and gamma is needed, which has been already reported by Archer et al [5]. Transmission data, for voltages of 30 and 35 kVp have been taken from Simpkin [6, 7].
Published transmission data by Simpkin [6] for concrete material have also been used. The high attenuation HVLs have been taken from Archer et al [5]. The two formulae are then in agreement, providing the same results. The situation that is examined draws attention to a method which allows more precise values of additional required material to be given in case of structural shielding in place.
This paper presents an extension of an existing method for calculating shielding requirements, for multiple X-ray tubes in a room operated at various beam qualities. The methodology computes the required shielding thickness such that the exposure behind it stays below a desired value. The presented method eliminates the overestimation of added shielding thickness which may occur using the other methods already mentioned.
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