Efficiency of biological versus physical optimization for single‐arc VMAT for prostate and head and neck cases

Abstract

The aim of this work was to compare different approaches to VMAT optimization (biological vs. physical DVH‐based) in two commercial treatment planning systems (TPS) for head and neck and prostate cases, using Pareto fronts. VMAT vs. IMRT Pareto front comparison was additionally performed in order to benchmark the optimizer efficiency and VMAT plan quality for each TPS. Three prostate and three head and neck cancer patients were selected for nine‐beam IMRT and single‐arc VMAT planning in Monaco 3.00 and Oncentra MasterPlan (OMP) 3.3 planning systems. Pareto fronts for prostate cases were constructed based on PTV coverage by 95% isodose and volume of rectum receiving 60 Gy or more. For head and neck cases, PTV coverage by the same isodose and mean dose to parotid gland were used for the construction of Pareto fronts. DVH analysis was performed together with evaluation of planning and delivery efficiency for all the plans. In the intersystem comparison for prostate plans, Monaco generated very similar IMRT and VMAT solutions. Quality of Monaco VMAT plans was superior compared to Oncentra in terms of conformity, homogeneity, and lower median dose to bladder due to biological formalism of optimization cost functions. For the head and neck cases, IMRT and VMAT plans were similar in both systems, except the case where a very strong modulation was required. In this situation single‐arc VMAT plan generated with OMP was inferior compared to IMRT. VMAT OMP solutions were similar to Monaco or slightly better for two less‐modulated head and neck cases. However, this advantage was achieved on the cost of lower conformity and homogeneity of the Oncentra VMAT plans. IMRT and VMAT solutions generated by Monaco were very similar for both prostate and head and neck cases. Oncentra system shows a bigger difference, and use of the dual‐arc VMAT would be recommended to achieve the same plan quality as nine‐field IMRT. Biological optimization seems beneficial in terms of plan conformity and homogeneity and allowed achieving lower OAR doses for prostate cases. In complex anatomical situations represented by head and neck cases, sequencing algorithm in Monaco imposed limitations on VMAT plan quality in the intersystem comparison.PACS numbers: 87.55.de, 87.55.dk, 87.53.Jw

A study of minimum segment width parameter on VMAT plan quality, delivery accuracy, and efficiency for cervical cancer using Monaco TPS

“…Over the last decade, volumetric modulated arc therapy (VMAT) has been explored and implemented to treat a variety of cancers including in the prostate, head and neck, lung, and spine 1, 2, 3, 4. VMAT is a dynamic treatment technique in which the radiation dose rates, gantry speeds, and movements of the multi‐leaf collimator and jaws are simultaneously varied while the beam is on 5.…”

The effect of body contouring on the dose distribution delivered with volumetric‐modulated arc therapy technique

“…Both IMRT and VMAT are of benefit to the treatment of prostate cancer, as well as head and neck (H&N) cancer, since organs at risk (OARs) in both cases are located close to the target volume, which is irradiated by a typically high prescription dose (4,5,11–13) . Many studies have demonstrated the clinical superiority of both IMRT and VMAT as compared to conventional non‐modulated modalities for the treatment of both prostate and H&N cancer (2,5,11–13) . Furthermore, technological advances in dose calculation algorithm development have enabled more accurate evaluation of treatment plans (14–17) .…”

“…Furthermore, technological advances in dose calculation algorithm development have enabled more accurate evaluation of treatment plans (14–17) . Through utilization of state‐of‐the‐art techniques in radiation therapy, in terms of both calculation and delivery, highly conformal treatment of both prostate and H&N cancer has become possible (2,4,5,12) . However, elaborate treatments with steep dose gradients generated using IMRT and VMAT techniques are more susceptible to errors than are conventional radiation therapy treatments (18,19) .…”

Βελτιστοποίηση Και Αξιολόγηση Σύγχρονων Εφαρμογών Ακτινοθεραπείας

“… Μαθηματική ανάλυση και οπτικοποίηση των αποτελεσμάτων (Σχήμα 30). [65] Σχήμα 29. Εισαγωγή εικόνων στο IMRT σύγκριση και ανάλυση.…”

“…Υπάρχουν αντίστοιχες μελέτες στη βιβλιογραφία όπου για τον καρκίνο κεφαλής τραχήλου (ρινοφάρυγγα) συγκρίνονται και αξιολογούνται οι τεχνικές IMRT και VMAT [58][59][60][61][62] . Λιγότερες είναι οι μελέτες στις οποίες συγκρίνονται οι αλγόριθμοι βελτιστοποίησης, οι οποίοι στηρίζονται σε βιολογικές ή φυσικές παραμέτρους για τη συγκεκριμένη μορφή καρκίνου [62][63][64][65].…”