International Journal of Radiation Research
نشریه پرتو پژوه
Int J Radiat Res
Basic Sciences
http://ijrr.com
79
journal79
2322-3243
2345-4229
10.61186/ijrr
en
jalali
1399
7
1
gregorian
2020
10
1
18
4
online
1
fulltext
en
Geometric distortion evaluation of magnetic resonance images by a new large field of view phantom for magnetic resonance based radiotherapy purposes
Medical Physics
Medical Physics
تحقيق بديع
Original Research
<div style="text-align: justify;">Background: The magnetic resonance imaging (MRI)-based radiotherapy planning method have been considered in recent years because of the advantages of MRI and the problems of planning with two images modality. The first step in MRI-based radiotherapy is to evaluate magnetic resonance (MR) images geometric distortion. Therefore, the present study aimed to evaluate system related geometric distortion by a new large field of view phantom. Materials and Methods: A homemade phantom with Perspex sheets and plastic pipes containing water was built for evaluating MR images distortion. The phantom size is 48×48×37 cm<sup>3</sup> and includes 325 water pipes. The study evaluated four different protocols from a 60 cm bore MAGNETOM® Symphony Syngo 1.5 T (Siemens). Results: It was found that the amount of distortion for all protocols is under 2 mm for the radial distances less than 10 cm (field of view (FOV) = 20 cm), but distortion increased in radial distances greater than 10 cm, and reached about 5 cm for radial distances greater than 25 cm. Conclusion: Geometric distortion of each MR scanner has been shown to be dependent on the radio frequency (RF) sequence pulse (Spin echo or Gradient echo) and image parameters (echo time (TE), repetition time (TR), and receiver band-width)). The geometric distortion could be ignored for the FOV<20 cm (for the head region), and must be evaluated and corrected for more FOVs before the MR only radiotherapy.</div>
Geometric distortion, phantom, computed tomography, magnetic resonance imaging, treatment planning radiotherapy.
733
742
http://ijrr.com/browse.php?a_code=A-10-2055-59&slc_lang=en&sid=1
A.
Rostami
7900319475328460016913
7900319475328460016913
No
Department of Medical Physics and Radiological Sciences, Faculty of Paramedical Sciences, Sabzevar University of Medical Sciences, Sabzevar, Iran
Sh.
Naseri
NaseriSH@mums.ac.ir
7900319475328460016914
7900319475328460016914
Yes
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
M.
Momennezhad
7900319475328460016915
7900319475328460016915
No
Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
H.
Zare
7900319475328460016916
7900319475328460016916
No
Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
K.
Anvari
7900319475328460016917
7900319475328460016917
No
Department of Radiotherapy Oncology and Cancer Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
H.R.
Sayah Badkhor
7900319475328460016918
7900319475328460016918
No
Kowsar MRI Center, Emam Reza Hospital, Mashhad, Iran