<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_raon-2022-0010_s_006">
<h3>Background</h3>
<p>Hypofractionated stereotactic body radiation therapy (SBRT) for prostate cancer (PCa) can be delivered with the robot-assisted CyberKnife (CK) system or on a linear accelerator using dynamic intensity-modulated radiotherapy (IMRT) or volumetric arc radiotherapy (VMAT). This retrospective study was performed to determine whether CK offers better dose distribution than IMRT and/or VMAT.</p>
</sec>
<sec id="j_raon-2022-0010_s_007">
<h3>Materials and methods</h3>
<p>Treatment plans for three techniques were prepared using the same treatment parameters (36.35 Gy, 7.25 Gy/fr). We evaluated target coverage, conformity index (CI), homogeneity index (HI), gamma index (GI), and organs at risk (OAR) constraints.</p></sec>
<sec id="j_raon-2022-0010_s_008">
<h3>Results</h3>
<p>The mean planning target volume (PTV) dose for CK (39.58 Gy) was significantly greater than VMAT or IMRT (both 36.25 Gy). However, CK resulted in a wider dose range (31.48 to 45.89 Gy) <italic>vs</italic>. VMAT and IMRT (34.6–38.76 Gy). The mean dose to the rectum (V36Gy, mm<sup>3</sup>) was significantly lower (p &lt; 0.001) in the CK plans (219.78 <italic>vs</italic>. 519.59 and 422.62, respectively). The mean bladder dose (V37Gy, mm<sup>3</sup>) was significantly greater for CK (3256 <italic>vs</italic>. 1090.75 for VMAT and 4.5 for IMRT (p &lt; 0.001). CK yielded significantly better CI (1.07 <italic>vs</italic>. 1.17 and 1.25 for VMAT and IMRT, respectively; p &lt; 0.01) and HI values (1.27 <italic>vs</italic>. 1.07 and 1.04; p &lt; 0.01). GI values for the δd = 3mm, δ% = 3% criteria were 99.86 (VMAT), 99.07 (IMRT) and 99.99 (CK). For δd = 2mm, δ% = 2%, the corresponding values were 98.3, 93.35, and 97.12, respectively.</p></sec>
<sec id="j_raon-2022-0010_s_009">
<h3>Conclusions</h3>
<p>For most variables, CK was superior to both VMAT and IMRT. However, dynamic IMRT techniques, especially VMAT, do not differ significantly from CK plans and are therefore acceptable alternatives to CyberKnife.</p>
</sec>
</abstract>

Background
Hypofractionated stereotactic body radiation therapy (SBRT) for prostate cancer (PCa) can be delivered with the robot-assisted CyberKnife (CK) system or on a linear accelerator using dynamic intensity-modulated radiotherapy (IMRT) or volumetric arc radiotherapy (VMAT). This retrospective study was performed to determine whether CK offers better dose distribution than IMRT and/or VMAT.


Materials and methods
Treatment plans for three techniques were prepared using the same treatment parameters (36.35 Gy, 7.25 Gy/fr). We evaluated target coverage, conformity index (CI), homogeneity index (HI), gamma index (GI), and organs at risk (OAR) constraints.

Results
The mean planning target volume (PTV) dose for CK (39.58 Gy) was significantly greater than VMAT or IMRT (both 36.25 Gy). However, CK resulted in a wider dose range (31.48 to 45.89 Gy) vs. VMAT and IMRT (34.6–38.76 Gy). The mean dose to the rectum (V36Gy, mm3) was significantly lower (p < 0.001) in the CK plans (219.78 vs. 519.59 and 422.62, respectively). The mean bladder dose (V37Gy, mm3) was significantly greater for CK (3256 vs. 1090.75 for VMAT and 4.5 for IMRT (p < 0.001). CK yielded significantly better CI (1.07 vs. 1.17 and 1.25 for VMAT and IMRT, respectively; p < 0.01) and HI values (1.27 vs. 1.07 and 1.04; p < 0.01). GI values for the δd = 3mm, δ% = 3% criteria were 99.86 (VMAT), 99.07 (IMRT) and 99.99 (CK). For δd = 2mm, δ% = 2%, the corresponding values were 98.3, 93.35, and 97.12, respectively.

Conclusions
For most variables, CK was superior to both VMAT and IMRT. However, dynamic IMRT techniques, especially VMAT, do not differ significantly from CK plans and are therefore acceptable alternatives to CyberKnife.

Does CyberKnife improve dose distribution versus IMRT and VMAT on a linear accelerator in low-risk prostate cancer?

Radiology and Oncology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Background
Hypofractionated stereotactic body radiation therapy (SBRT) for prostate cancer (PCa) can be delivered with the robot-assisted CyberKnife (CK)...

Does CyberKnife improve dose distribution versus IMRT and VMAT on a linear accelerator in low-risk prostate cancer?

Article Category: Research Article

Published Online: Mar 28, 2022

Page range: 259 - 266

Received: Oct 21, 2021

Accepted: Jan 31, 2022

DOI: https://doi.org/10.2478/raon-2022-0010

© 2022 Dorota Maria Borowicz, Agnieszka Skrobała, Marta Kruszyna-Mochalska, Julian Malicki, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.