For each of the two OCTAVIUS tops (Standard and SRS), we measured PDD curves in water for all available photon energies (6X, 10X, 15X, 6FFF, and 10FFF) up to 300 mm depth.
In the code of practice, PTW recommends to acquire PDD data in a water phantom by means of a commonly used ion chamber (e.g. Semiflex 0.125cm3) for field sizes down to 4x4 cm, and a diode detector (T60016) for smaller field sizes (diode detectors T60017, T60018, Diamond T60003 or microLion T31018 are also suitable).
We used the PTW microDiamond detector (T60019) for all field sizes. Beyond dmax, step size was 2.5 mm. Time per point was 0.5 s.
In Mephysto 3.2 DataAnalyze, curves were smoothed twice. In Mephysto TableGenerator, curves were manipulated according to the OCTAVIUS 4D manual (normalize to individual maximum, extrapolate for field size 0 x 0 cm, interpolate for all missing field sizes, normalize again).
The OCTAVIUS top Standard (T40063.1.004) has a diameter of 320 mm. The required SSD is 85 cm.
PTW recommends to measure the following square field sizes: (2 optional), 3, 4, 5, 8, 10, 12, 15, 20, 25, and 26 cm. Only the field sizes in bold are mandatory.
We measured the square field sizes 2, 3, 4, 5, 8, 10, 12, 15, 20, 25, and 26 cm using the microDiamond.
For the Standard top, you can download the following zipped archives:
The OCTAVIUS top SRS (T40063.1.002) has a diameter of 170 mm. The required SSD is 92 cm.
We measured the square field sizes 2, 3, 4, 5, 8, 10, 12, and 15 cm using the microDiamond.
For the SRS top, you can download the following zipped archives:
Keep in mind that these PDD curves are machine specific. Do not use them for the verification of your clinical plans! They are just for comparison purposes!