The Australian Clinical Dosimetry Service (ACDS) has provided dosimetric audits to radiotherapy facilities throughout Australia since 2011.
During this time it has established a national data set from all the audit results.
Interrogating the national data set has allowed the ACDS to establish baseline characteristics for radiotherapy clinics,
and provide advice to clinics which recognizes the equipment the clinics employ.
In 2016 the ACDS introduced IMRT and VMAT capability for the Level II and III audits which,
in a first for the ACDS,
Methods and materials
The Level II uses the TG-119 C-shape” target,
and add additional diagnostic tests; the Van Esch “Chair” test  and the nested “four L” test from Elekta commissioning tests.
The plans are measured with the PTW Octavius 1500 array in a solid water and lung slab phantom which are shown in Figure 1 a) and b) respectively.
The LIII audit alsouses the “C-shape” target volume from AAPM TG119 (with and without lung,
Figure 2 b) and a) respectively) and the “Complex case” with two adjacent...
Both Level II and III audits include measurements in a defined low dose region in the centre of a wrap-around C-shape (LII case 14 and LIII case 6 – no lung; LII case 15 and LIII case 7 – with lung).
The Level III audit also includes a “complex case” with two adjacent target structures and a fully encapsulated low dose region (case 8).
Figures3 and4 show the mean local dose difference in the exclusion volume as a function of mean measured dose in the...
The ACDS dataset of VMAT and IMRT audits is beginning to demonstrate characteristic behavior which could inform how to plan for optimal outcomes within exclusion zones.
It is also beginning to demonstrate limitations in different commercial algorithms and how high a priority can be given to driving the dose down within an exclusion volume.
LoSasso TJ and Mechalakos JG,
Yue NH and Xiao Y.
(2009) IMRT Commissioning: Multiple institution planning and dosimetry comparisons,
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