• Title/Summary/Keyword: Intensity-modulated

Search Result 421, Processing Time 0.016 seconds

Compare to Evaluate the Imaging dose of MVCT and CBCT (Tomotherapy MVCT와 Linac CBCT의 Imaging dose 비교평가)

  • Yoon, Bo Reum;Hong, Mi Lan;Ahn, Jong Ho;Song, Ki Won
    • The Journal of Korean Society for Radiation Therapy
    • /
    • v.26 no.1
    • /
    • pp.83-89
    • /
    • 2014
  • Purpose : In case of the intensity modulated radiation therapy (IMRT) using Tomotherapy and linear accelerator (Linac), it was to compare and to evaluate the imaging dose of MVCT and CBCT that were performed daily for the correct set up of the patient. Materials and Methods : The human body model Phantom (Anderson rando Phantom, USA) was divided into the three parts as Head, Thorax, pelvis, and after GafChromic EBT3 film cut to the size of $0.5{\times}0.5cm2$.in the center of the recording area were situated on the ant, post, left, and right surface of the phantom and 2cm in depth from the ant, post, left, right, and center surface of the phantom, the surface dose and inner dose were measured repeatedly three times, respectively, using the tomotherapy (Hi Art) and the OBI of NovalisTx. The measured film calculated the output value by RIP version6.0 and then the average value of the dose was calculated by the one-way analysis of variance. Results : Using the human body model phantom, the results of MVCT and CBCT performance were that measurements of MVCT inner dose were showed $15.43cGy{\pm}6.05$ in the head, $16.62cGy{\pm}3.08$ in the thorax, $16.81cGy{\pm}5.24$ in the pelvis, and measurements of CBCT inner dose were showed $13.28{\pm}3.68$ in the head, from $13.66{\pm}4.04$ in the thorax, $15.52{\pm}3.52$ in the pelvis. The measurements of surface dose were showed in case of MVCT performance, $11.64{\pm}4.05$ in the head, $12.16{\pm}4.38$ in the thorax, $12.05{\pm}2.71$ in the pelvis, and in case of CBCT performance, $14.59{\pm}3.51$ in the head, $15.82{\pm}2.89$ in the thorax, $17.48{\pm}2.80$ in the pelvis, respectively. Conclusion : In case of Inner dose, the MVCT using MV energy showed higher than the CBCT using kV energy at 1.16 times in the head, at 1.22 times in the thorax, at 1.08 times in the pelvis, and in case of surface dose, the CBCT was higher than MVCT, at 1.25 times in the head, at 1.30 times in the thorax, at 1.45 times in the pelvis. Imaging dose was a small amount compared to the therapeutic dose but it was thought to affect partially to normal tissue because it was done in daily schedule. However, IMRT treatment was necessarily parallel with the IGRT treatment through the image-guide to minimize errors between planned and actual treatment. Thus, to minimize imaging dose that the patients receive, when planning the treatment, it should be set up a treatment plan considering imaging dose, or it must be performed by minimizing the scan range when shooting MVCT.