跳至主要内容

Investigation of Scattered Radiation Dose at the Door of a Radiotherapy Vault When the Maze Intersects the Primary Beam

Read full paper at:
http://www.scirp.org/journal/PaperInformation.aspx?PaperID=54192#.VPAx-SzQrzE

NCRP 151 provides very detailed examples demonstrating the necessary concerns for shielding a conventional radiotherapy vault with a maze where the useful beam is parallel to the maze. However, it provides little guidance on how to properly shield a vault with the maze-wall acting as part of a compound primary barrier. We have modeled a new radiotherapy vault with this configuration and assessed the additional photon shielding burden at the door with MCNP5. MCNP simulations demonstrated an increase in overall photon shielding burden at the door relative to calculations that only consider photon workloads presented in NCRP 151. Two additional components of scattered radiation are considered and methods for calculation are presented.
Cite this paper
Tanny, S. , Sperling, N. and Parsai, E. (2015) Investigation of Scattered Radiation Dose at the Door of a Radiotherapy Vault When the Maze Intersects the Primary Beam. Journal of Modern Physics, 6, 141-149. doi: 10.4236/jmp.2015.62019. 
 

[1] National Council on Radiation Protection and Measurements (2005) Structural Shielding Design and Evaluation for Megavoltage X- and Gamma-Ray Radiotherapy Facilities.
[2] Facure, A., Cardoso, S.C., da Rosa, L.A.R. and da Silva, A.X. (2010) Radiation Protection Dosimetry, 138, 251-256.
http://dx.doi.org/10.1093/rpd/ncp245
[3] Biggs, P. (1991) Health Physics, 62, 465-472.
http://dx.doi.org/10.1097/00004032-199110000-00001
[4] X-5 Monte Carlo Team (2005) LA-UR-03-1987. Los Alamos National Laboratory, USA.
[5] Mohan, R., Chui, C. and Lidosfsky, L. (1985) Medical Physics, 12, 592-597.
http://dx.doi.org/10.1118/1.595680
[6] Williams III, R.G., Gesh, C.J. and Pagh, R.T. (2006) Pacific Northwest National Laboratory, 14-18.
[7] McGinley, P. (2002) Shielding Techniques for Radiation Oncology Facilities. 2nd Edition, Medical Physics Publishing, Madison.
[8] Taylor, P.L., Rodgers, J.E. and Shobe, J. (1999) Medical Physics, 26, 1442-1446.
http://dx.doi.org/10.1118/1.598670
[9] Shobe, J., Rodgers, J.E. and Taylor, P.L. (1999) Health Physics, 76, 25-35.
http://dx.doi.org/10.1097/00004032-199901000-00005      eww150227lx
标签：

评论

发表评论

此博客中的热门博文

Incorporation of High-Altitude Balloon Experiment in High School Science Classrooms

High-altitude balloon is a balloon, filled usually with helium or hydrogen that ascends into an area called “near space” or stratosphere. The most common type of high-altitude balloons are weather balloons. Other purposes include use as a platform for experiments in the upper atmosphere. Modern balloons generally contain electronic equipment such as radio transmitters, cameras, or satellite navigation systems, such as GPS receivers. The mission of the High-Altitude Balloon Experiment (HABE) is to acquire supporting data, validate enabling technologies, and resolve critical acquisition, tracking, and pointing (ATP) and fire control issues in support of future space-based precision pointing experiments. The use of high-altitude balloons offers a relatively low-cost, low-vibration test platform, a recoverable and reusable payload, worldwide launch capability, and a 'near- space' emulation of the future space systems operational scenarios. More recently, several university...
1 条评论
阅读全文

The Influence of Heated Soil in Crop of “Tamaris” Tomato Plants on the Biological Activity of the Rhizosphere Soil

Tomato is a plant with high heat requirements and sensitive to cold weather and frost. The optimum temperature for the growth of tomato plants is between 21˚C and 27˚C during the day and between 17˚C and 21˚C at night. The soil temperature is also very important for plant growth. The optimum soil temperature for tomato cultivation should be within the range 15˚C - 18˚C. Besides, the proper development of the root system depends on the optimal temperature of the soil. A temperature below 14˚C reduces and inhibits the growth of the root system and encourages the development of fungal and bacterial diseases. In this study, the authors aimed to evaluate the effect of heated soil on the population of bacteria, fungi and nematodes inhabiting the soil of tomato cultivar “Tamaris” growing in peat and coconut substrates. The experiment was carried out in 12 treatments and in 3 replications (one slab was one replication). The soils were tested in two different types of containers: cylinders...
发表评论
阅读全文

Effect of Proline Pretreatment on Grapevine Shoot-Tip Response to a Droplet-Vitrification Protocol

Proline is an α-amino acid that is used in the biosynthesis of proteins. Some studies have shown that proline has been accumulated in plants in response to biotic and abiotic stresses. Exogenous proline has thus been used for improving some plant cryopreservation protocols. Further enhancement of cryopreservation efficiency for  in vitro  grapevines could be expected if stresses linked to cryopreservation procedures could be reduced. In this study, the authors studied the possible beneficial effect of proline in grapevine cryopreservation. Single-node explants from  in vitro  grown grapevine plantlets ( Vitis vinifera  L. cv Portan) were cultured on shooting media (half-strength MS + 1 μM BAP) containing no proline (control) or 50, 500, or 2000 μM filter-sterilized L-proline. Shoot tips excised from these microshoots were subjected to a PVS2-based droplet-vitrification procedure. Control and rewarmed explants were grown on a recovery medium containing ...
发表评论
阅读全文