ESTRO 2024 - Abstract Book

S5445

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

mGy for pelvic protocols and 1.5 mGy for the chest protocols with the 100 mm ionisation chamber. Additionally, for the 0.6 cc Farmer chamber, there were differences for each CBCT in the head and neck protocols of 2.2 mGy, 16.6 mGy for the pelvic protocols and 1.4 mGy for the chest protocols.

The best SNR is obtained at the voltage of 60 kV and slowly starts to decrease, until above 130 kV.

Table 1 shows the relative variation in the absorbed dose by each organ for a voltage of 60 kV and the kV values supplied by the manufacturer.

Table 1 - Relative variation of absorbed dose between the kV values supplied by the manufacturer versus 60 kV.

Phantom 10F

Phantom 15F

Organ

Thorax

Head

Pelvis

Thorax

Head

Pelvis

- 16.71% - 62.12% - 49.36% - 75.06% - 62.98% 3.10% - 64.39% - 77.06% - 20.91% - 60.14% -0.17% - 11.34% - 13.48% - 69.18% -

- 70.66%

-

- 6.50%

- 65.39%

-

Bladder

- 52.36%

- 35.50%

- 59.60%

- 50.88%

- 36.25%

Brain

20.15%

- 24.72%

- 69.20%

10.47%

- 28.77%

Breast

- 66.65%

18.65%

-

- 71.09%

18.64%

Eyes

- 12.17%

- 59.64%

- 73.12%

- 14.92%

- 60.08%

Heart wall

- 55.76%

-

- 58.71%

- 61.64%

-

Kidney

-

-

- 23.76%

-

-

Left colon

- 22.13%

-

- 64.84%

- 27.90%

-

Liver

- 9.73%

- 57.08%

- 73.97%

- 8.45%

- 55.23%

Lung

- 24.59%

- 60.31%

-

- 32.72%

- 64.02% -

Oesophagus

- 68.40%

-

- 17.51%

- 37.97%

- 68.29%

Ovaries

- 49.14%

-

- 57.52%

- 56.30%

-

Pancreas

-

-

- 12.51%

-

-

Right colon

Small intestine content

-

-

- 10.12%

-

-

Small intestine wall

-

-

- 11.58%

-

-

- 42.82%

-

- 66.14%

- 49.00%

-

Spleen