Comparison of an anthropomorphic PRESAGE® dosimeter and radiochromic film with a commercial radiation treatment planning system for breast IMRT: a feasibility study

Abstract

This work presents a comparison of an anthropomorphic PRESAGE® dosimeter and radiochromic film measurements with a commercial treatment planning system to determine the feasibility of PRESAGE® for 3D dosimetry in breast IMRT. An anthropomorphic PRESAGE® phantom was created in the shape of a breast phantom. A five‐field IMRT plan was generated with a commercially available treatment planning system and delivered to the PRESAGE® phantom. The anthropomorphic PRESAGE® was scanned with the Duke midsized optical CT scanner (DMOS‐RPC) and the OD distribution was converted to dose. Comparisons were performed between the dose distribution calculated with the Pinnacle3 treatment planning system, PRESAGE®, and EBT2 film measurements. DVHs, gamma maps, and line profiles were used to evaluate the agreement. Gamma map comparisons showed that Pinnacle3 agreed with PRESAGE® as greater than 95% of comparison points for the PTV passed a ±3%/±3thinmathspacemm criterion when the outer 8 mm of phantom data were discluded. Edge artifacts were observed in the optical CT reconstruction, from the surface to approximately 8 mm depth. These artifacts resulted in dose differences between Pinnacle3 and PRESAGE® of up to 5% between the surface and a depth of 8 mm and decreased with increasing depth in the phantom. Line profile comparisons between all three independent measurements yielded a maximum difference of 2% within the central 80% of the field width. For the breast IMRT plan studied, the Pinnacle3 calculations agreed with PRESAGE® measurements to within the ±3%/±3thinmathspacemm gamma criterion. This work demonstrates the feasibility of the PRESAGE® to be fashioned into anthropomorphic shape, and establishes the accuracy of Pinnacle3 for breast IMRT. Furthermore, these data have established the groundwork for future investigations into 3D dosimetry with more complex anthropomorphic phantoms.PACS number: 87.53.Jw, 87.55.D‐, 87.55.dk

Dosimetric feasibility of an anthropomorphic three-dimensional PRESAGE® dosimeter for verification of single entry hybrid catheter accelerated partial breast brachytherapy

“…The maximum per cent dose difference was 4% between Oncentra ® and PRESAGE ® . Preliminary investigations suggest the cause may be a reflection artefact of laser light from the underside of the top and bottom of the dosimeter 32 Figure 5(a) Comparison of the calculated and measured point skin doses for PRESAGE ® , Oncentra ® Brachy Planning TPS and EBT2 film for film 1.…”

Dosimetric characterisation of anthropomorphic PRESAGE® dosimeter and EBT2 film for partial breast radiotherapy

“…The PRESAGE ® PTV DVH indicates that the delivered dose was somewhat less homogeneous than that calculated using the Pinnacle 3 treatment planning system, with a maximum of 2.2% of small regions of the relationship above and below the dose occurring near the edge of the breast phantom. The average difference in the target volume was 1.5% with a standard deviation of 0.49%, and a part of this difference is real, whereas some of it was due to artefacts in the PRESAGE ® distribution 15 …”

“…Scans normalised the calculated dose distribution and 3D comparison was made with a treatment planning system 16 . The DMOS-RPC scanner shown in Figure 1 (left) consists of a matched telemetry source and image lenses provide visual field 15 . In graphical user interface, the top-left quadrants of projection screen images are associated with painting on preliminary irradiation, and the bottom-left projection screens are associated with the image scan after irradiation.…”

“…Independent verification of dose distribution was carried out using GAFCHROMIC ® EBT2 film (ISP Corp., Wayne, NJ, USA). Temporal stability, independence, comfort and self-oriented development are the basic reasons for using EBT2 15 16 Once the treatment plan was implemented, the PRESAGE ® dosimeter was cut into two levels, which correspond approximately parallel to the axial planes, and pieces of EBT2 film were placed between the sections of PRESAGE ® .…”

“…PRESAGE ® can be carried out in various shapes but most of the previous work has been performed using cylindrical shapes. The present study uses a breast-shaped anthropomorphic PRESAGE ® dosimeter for verification of three-field dose distribution 15 . The present study also uses qPRESAGE ® dosimeters to build on earlier work by applying the PRESAGE ® /optical-CT system for the verification of three-field delivery, in which the accuracy of commercial treatment planning systems is less well known.…”