scholarly journals Three-dimensional printer-generated patient-specific phantom for artificial in vivo dosimetry in radiotherapy quality assurance

2017 ◽  
Vol 44 ◽  
pp. 205-211 ◽  
Author(s):  
Takeshi Kamomae ◽  
Hidetoshi Shimizu ◽  
Takayoshi Nakaya ◽  
Kuniyasu Okudaira ◽  
Takahiro Aoyama ◽  
...  
2016 ◽  
Author(s):  
◽  
Jason Stanford

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Advance treatment techniques, such as IMRT and dynamic conformal arc delivery, are novel radiation treatment procedures at the forefront of accurate and precise radiotherapy. However, the risk of suboptimal treatment resulting in injury is far greater with these techniques due to their complexity. An in vivo quality assurance system is the most appropriate validation of the delivered dose to the patient from these techniques. The intent of this research is to propose an in vivo dosimetry quality assurance procedure using radiochromic film. This research proved that radiochromic in vivo dosimetry is a viable method of detecting spatial patient specific errors in radiotherapy; however, the process is time consuming and not sensitive enough for dosimetric errors associated with weight change. Although time consuming, in vivo radiochromic dosimetry is an attractive alternative for small cancer centers and developing countries without the large startup capital to acquire the electronic portal imaging device necessary for EPID in vivo dosimetry.


2007 ◽  
Vol 67 (1) ◽  
pp. 288-295 ◽  
Author(s):  
Hansjoerg Wertz ◽  
Judit Boda-Heggemann ◽  
Cornelia Walter ◽  
Barbara Dobler ◽  
Sabine Mai ◽  
...  

Author(s):  
David M. Pierce ◽  
Thomas E. Fastl ◽  
Hannah Weisbecker ◽  
Gerhard A. Holzapfel ◽  
Borja Rodriguez-Vila ◽  
...  

Through progress in medical imaging, image analysis and finite element (FE) meshing tools it is now possible to extract patient-specific geometries from medical images of, e.g., abdominal aortic aneurysms (AAAs), and thus to study clinically relevant problems via FE simulations. Medical imaging is most often performed in vivo, and hence the reconstructed model geometry in the problem of interest will represent the in vivo state, e.g., the AAA at physiological blood pressure. However, classical continuum mechanics and FE methods assume that constitutive models and the corresponding simulations start from an unloaded, stress-free reference condition.


1999 ◽  
Vol 1 (2) ◽  
pp. 73-82
Author(s):  
Robert Appleyard

A clear rationale exists for routine in vivo dosimetry as part of an overall quality assurance (QA) programme within a radiotherapy department. A survey was undertaken in order to identify the extent of diode dosimetry practice within the UK.Questionnaires were distributed to 57 radiotherapy physics departments in the UK in order to determine the extent of central axis diode dosimetry and the protocols implemented, the range of other in vivo measurements performed using diodes and the type of equipment used. Fifty-four responses were received. Eighteen departments undertook some form of central axis entrance dosimetry. Fifteen departments could be considered to be doing this routinely. Seven departments indicated planned future use. Six centres routinely undertook exit dosimetry with a further 3 indicating planned future use. Varied protocols for use were reported by those centres undertaking central axis dosimetry. Thirty-two respondents used a diode system for other forms of in vivo measurements with critical organ and TBI dosimetry being the most common. The vast majority used Scanditronix equipment.Despite the distinct benefits of central axis diode dosimetry, this continues to be infrequently adopted as part of a departmental QA programme. However, an indication of a number of departments planning to implement such an approach is reassuring.


2016 ◽  
Vol 119 ◽  
pp. S389
Author(s):  
A. Carnicer Caceres ◽  
V. Letellier ◽  
G. Angellier ◽  
V. Floquet ◽  
W. Sauerwein ◽  
...  

2021 ◽  
Vol 11 ◽  
Author(s):  
Yeonho Choi ◽  
Ik Jae Lee ◽  
Kwangwoo Park ◽  
Kyung Ran Park ◽  
Yeona Cho ◽  
...  

This study aims to confirm the usefulness of patient-specific quality assurance (PSQA) using three-dimensional (3D)-printed phantoms in ensuring the stability of IORT and the precision of the treatment administered. In this study, five patient-specific chest phantoms were fabricated using a 3D printer such that they were dosimetrically equivalent to the chests of actual patients in terms of organ density and shape around the given target, where a spherical applicator was inserted for breast IORT treatment via the INTRABEAM™ system. Models of lungs and soft tissue were fabricated by applying infill ratios corresponding to the mean Hounsfield unit (HU) values calculated from CT scans of the patients. The two models were then assembled into one. A 3D-printed water-equivalent phantom was also fabricated to verify the vendor-provided depth dose curve. Pieces of an EBT3 film were inserted into the 3D-printed customized phantoms to measure the doses. A 10 Gy prescription dose based on the surface of the spherical applicator was delivered and measured through EBT3 films parallel and perpendicular to the axis of the beam. The shapes of the phantoms, CT values, and absorbed doses were compared between the expected and printed ones. The morphological agreement among the five patient-specific 3D chest phantoms was assessed. The mean differences in terms of HU between the patients and the phantoms was 2.2 HU for soft tissue and −26.2 HU for the lungs. The dose irradiated on the surface of the spherical applicator yielded a percent error of −2.16% ± 3.91% between the measured and prescribed doses. In a depth dose comparison using a 3D-printed water phantom, the uncertainty in the measurements based on the EBT3 film decreased as the depth increased beyond 5 mm, and a good agreement in terms of the absolute dose was noted between the EBT3 film and the vendor data. These results demonstrate the applicability of the 3D-printed chest phantom for PSQA in breast IORT. This enhanced precision offers new opportunities for advancements in IORT.


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