%0 Journal Article
%T Investigation of Well-Balanced kV X-Ray Imaging Conditions between Skin Dose and Image Noise for Dynamic Tumor Tracking Irradiation
%A Takahiro Nakai
%A Akira Sawada
%A Hiroaki Tanabe
%A Masaki Sueoka
%A Sho Taniuchi
%A Kenji Takayama
%A Takehiro Shiinoki
%A Yoshitomo Ishihara
%A Masaki Kokubo
%J International Journal of Medical Physics,Clinical Engineering and Radiation Oncology
%P 410-420
%@ 2168-5444
%D 2017
%I Scientific Research Publishing
%R 10.4236/ijmpcero.2017.64037
%X <b><span>Purpose:</span></b><span> The purposes of this study were to estimate
accumulated kV X-ray imaging dose throughout dynamic tumor tracking (DTT)
irradiation</span><span> </span><span>by Vero</span><span> </span><span><span>4DRT system and to address an analytical skin dose
formula for well-balanced </span><span>kV X-ray imaging
conditions between skin dose and image noise.</span></span><span> </span><b><span>Method:</span></b><span> <span>First, </span><span>skin dose was measured using kV X-ray tube,
chamber, and water-equivalent</span><span> phan</span><span>toms.
Next, imaging dose for six patients in DTT treatment was computed</span><span> using
log files. Subsequently, scattered dose </span><span>ratio</span></span><span> </span><span>was calculated by amount of io</span><span>nization in front of flat panel
detector (FPD) for fields with size of maximum</span><span><span> and </span><span>the chamber
for 0</span></span><span> </span><span>-</span><span> </span><span>200 mm-thickness phantoms and
tube voltage of 60, 80,</span><span> 100, 120 kV, respectively. Furthermore, image noise was computed from
FPD im</span><span><span>ages. </span><b><span>Results:</span></b><span> The skin dose was greater by a factor of 1.4</span></span><span> </span><span>-</span><span> </span><span>1.6 than those in Synergy XVI system.</span><span> </span><span>The image noise in FPD, </span><span><span></span><span>&nbsp;was ex</span><span><span>pressed </span><span>as</span></span><span> &lt;i&gt;N&lt;/i&gt;
= 0.045</span><span>กม</span><span>(1/&lt;i&gt;Q&lt;sub&gt;FPDen&lt;/sub&gt;&lt;/i&gt;)&lt;sup&gt;0.479&lt;/sup&gt;, </span><span>where </span><span>&lt;i&gt;Q&lt;sub&gt;FPDen&lt;/sub&gt;&lt;/i&gt;</span><span> denotes amount of ionization
in</span><span> front
of FPD. Then, skin dose,</span><span> &lt;i&gt;D (N, t, v)&lt;/i&gt;</span><span> was formulated as</span><span> (0.045/&lt;i&gt;N&lt;/i&gt;)&lt;sup&gt;(1/0.479)&lt;/sup&gt;/&lt;i&gt;Q&lt;sub&gt;FPDen/mAs&lt;/sub&gt;&lt;/i&gt;
(&lt;i&gt;t&lt;/i&gt;, &lt;i&gt;v&lt;/i&gt;) </span><span>กม</span><span>&lt;i&gt;D&lt;sub&gt;/mAs&lt;/sub&gt;&lt;/i&gt; (&lt;i&gt;v&lt;/i&gt;),</span><span> </span><span>where</span><span> &lt;i&gt;Q&lt;sub&gt;FPDen/mAs&lt;/sub&gt;&lt;/i&gt;
(&lt;i&gt;t&lt;/i&gt;, &lt;i&gt;v&lt;/i&gt;)</span><span> and</span><span> &lt;i&gt;D&lt;sub&gt;/mAs&lt;/sub&gt;&lt;/i&gt;
(&lt;i&gt;v&lt;/i&gt;)</span><span> denote amount of ionization in front of FPD</span><span> </span><span>and skin dose per</span><span><span> mAs, </span><span>respectively. </span></span><span>Using the formulae, it
%K Dynamic Tumor Tracking Irradiation
%K Skin Dose
%K Vero4DRT
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=80349