A bias‐free, automated planning tool for technique comparison in radiotherapy ‐ application to nasopharyngeal carcinoma treatments

Abstract

In this study a novel, user‐independent automated planning technique was developed to objectively compare volumetric‐modulated arc therapy (VMAT) and intensity‐modulated radiotherapy (IMRT) for nasopharyngeal carcinoma planning, and to determine which technique offers a greater benefit for parotid‐sparing and dose escalation strategies. Ten patients were investigated, with a standard prescription of three dose levels to the target volumes (70, 63, and 56 Gy), using a simultaneous integrated boost in 33 fractions. The automated tool was used to investigate three planning strategies with both IMRT and VMAT: clinically acceptable plan creation, parotid dose sparing, and dose escalation. Clinically acceptable plans were achieved for all patients using both techniques. For parotid‐sparing, automated planning reduced the mean dose to a greater extent using VMAT rather than IMRT (17.0 Gy and 19.6 Gy, respectively, p<0.01). For dose escalation to the mean of the main clinical target volume, neither VMAT nor IMRT offered a significant benefit over the other. The OAR‐limiting prescriptions for VMAT ranged from 84‐98 Gy, compared to 76‐110 Gy for IMRT. Employing a user‐independent planning technique, it was possible to objectively compare VMAT and IMRT for nasopharyngeal carcinoma treatment strategies. VMAT offers a parotid‐sparing improvement, but no significant benefit was observed for dose escalation to the primary target.PACS numbers: 87.55.D‐, 87.55.kd

Automation in intensity modulated radiotherapy treatment planning—a review of recent innovations

“…One approach to solve this is to automate the iterative adjustment of the optimisation objectives and constraints. [86][87][88]98,[104][105][106][107][108][109][110] The basic idea is to start with a user-defined template which has the required clinical objectives. The user can then input the priorities for mandatory (hard) constraints.…”

“…163,166,173,181,192 Boylan and Rowbottom developed a PB-AIO approach and applied it in comparing seven fixed-field IMRT with two arc VMAT for nasopharyngeal head and neck cancer patients using a standard protocol, and to investigate two experimental strategies (a parotid-sparing strategy and dose escalation strategy). 192 They showed that the IMRT and VMAT techniques were clinically comparable for the standard and dose escalation protocols, whereas VMAT was better in the parotid sparing strategy. Lechner et al, used MCO to objectively compare the quality of flattening filter free IMRT and VMAT vs flattening filter plans in prostate and head and neck cancer patients.…”

Detailed evaluation of an automated approach to interactive optimization for volumetric modulated arc therapy plans

“…11 Both approaches have been investigated and implemented for IMRT. As noted by Chen et al 33 however, because of the rather complex computations, application to VMAT treatment planning is limited and reported studies either used relatively straightforward patient geometries 17,34 or used DVH information from MCO IMRT treatments to generate VMAT plans. 33,35 Potential limitations of this study include the following.…”

“…A more automated approach to treatment planning reduces human-machine interaction, helping to address the increasingly demanding planning environment, and may improve planning consistency and quality. Different (semi) automatic solutions have been reported, such as knowledge-based planning and multicriteria optimization (MCO), [7][8][9][10][11] and although these have obtained promising initial results, [12][13][14][15][16][17][18] there is limited data concerning the combination of more complex disease sites and VMAT. [19][20][21] In a recent publication, 21 we focused on the technical development of an in-house developed approach to automatic interactive optimization (AIO) for RapidArc ® VMAT planning in the Eclipse™ treatment planning system (Varian Medical Systems, Palo Alto, USA) for which we investigated the influence of different parameter settings.…”

Baş Boyun Radyoterapisinde Farklı Tedavi Teknikleri İle Simultane Integre Boost Yönteminin Karşılaştırılması

“…Spinal kord ortalama D max (cGy) değeri açısından planlar 27 arasında önemli farklar görülmezken, en düşük doz değeri 2 Ark YAAT tekniği ile elde edilmiştir. Boylan C. ve arkadaşlarının [23] ve White P. ve arkadaşlarının çalışmalarında [25] baş boyun kanserli hastalar için 7 Alan YART ile 2 Ark YAAT teknikleri karşılaştırılmış, beyin sapı ve spinal kord D max (cGy) değeri açısından çalışmamızla uyumlu olarak teknikler arasında anlamlı fark olmadığı görülmüştür. 7-9 Alan YART ve 2 Ark YAAT tekniklerinde sağ göz, sağ lens, sağ parotis ve sol parotis ortalama D ort (cGy) değerleri 1 Ark YAAT tekniğine göre daha küçük bulunmuştur.…”