Limits...
Dosimetric verification of gated delivery of electron beams using a 2D ion chamber array.

Yoganathan SA, Das KJ, Raj DG, Kumar S - J Med Phys (2015 Apr-Jun)

Bottom Line: These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target.The dosimetric characteristics of gated deliveries were compared with non-gated deliveries.The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.

ABSTRACT
The purpose of this study was to compare the dosimetric characteristics; such as beam output, symmetry and flatness between gated and non-gated electron beams. Dosimetric verification of gated delivery was carried for all electron beams available on Varian CL 2100CD medical linear accelerator. Measurements were conducted for three dose rates (100 MU/min, 300 MU/min and 600 MU/min) and two respiratory motions (breathing period of 4s and 8s). Real-time position management (RPM) system was used for the gated deliveries. Flatness and symmetry values were measured using Imatrixx 2D ion chamber array device and the beam output was measured using plane parallel ion chamber. These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target. The dosimetric characteristics of gated deliveries were compared with non-gated deliveries. The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries. The beam output variation of gated electron beam was less than 0.6 % for all electron energies except for 16 MeV (1.4 %). Based on the results of this study, it can be concluded that Varian CL2100 CD is well suitable for gated delivery of non-dynamic electron beams.

No MeSH data available.


Comparison of dose profiles for gated (25% duty cycle) and non-gated delivery of 9 MeV electron beam (a) In-pane and (b) Cross-plane. These profiles were measured at a depth of Zref using the applicator 20×20 cm2
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4478647&req=5

Figure 2: Comparison of dose profiles for gated (25% duty cycle) and non-gated delivery of 9 MeV electron beam (a) In-pane and (b) Cross-plane. These profiles were measured at a depth of Zref using the applicator 20×20 cm2

Mentions: Figure 2a and b show in-plane and cross-plane dose profiles of 9 MeV electron beam at a dose rate of 300 MU/min and breathing period 4s for gated and non-gated deliveries. Table 1a and b show the variation in beam flatness and symmetry values for all electron energies and various dose rates at 4 s breathing period. Similarly the Table 2a and b show the beam flatness and symmetry values for 8 s breathing period.


Dosimetric verification of gated delivery of electron beams using a 2D ion chamber array.

Yoganathan SA, Das KJ, Raj DG, Kumar S - J Med Phys (2015 Apr-Jun)

Comparison of dose profiles for gated (25% duty cycle) and non-gated delivery of 9 MeV electron beam (a) In-pane and (b) Cross-plane. These profiles were measured at a depth of Zref using the applicator 20×20 cm2
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4478647&req=5

Figure 2: Comparison of dose profiles for gated (25% duty cycle) and non-gated delivery of 9 MeV electron beam (a) In-pane and (b) Cross-plane. These profiles were measured at a depth of Zref using the applicator 20×20 cm2
Mentions: Figure 2a and b show in-plane and cross-plane dose profiles of 9 MeV electron beam at a dose rate of 300 MU/min and breathing period 4s for gated and non-gated deliveries. Table 1a and b show the variation in beam flatness and symmetry values for all electron energies and various dose rates at 4 s breathing period. Similarly the Table 2a and b show the beam flatness and symmetry values for 8 s breathing period.

Bottom Line: These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target.The dosimetric characteristics of gated deliveries were compared with non-gated deliveries.The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiotherapy, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.

ABSTRACT
The purpose of this study was to compare the dosimetric characteristics; such as beam output, symmetry and flatness between gated and non-gated electron beams. Dosimetric verification of gated delivery was carried for all electron beams available on Varian CL 2100CD medical linear accelerator. Measurements were conducted for three dose rates (100 MU/min, 300 MU/min and 600 MU/min) and two respiratory motions (breathing period of 4s and 8s). Real-time position management (RPM) system was used for the gated deliveries. Flatness and symmetry values were measured using Imatrixx 2D ion chamber array device and the beam output was measured using plane parallel ion chamber. These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target. The dosimetric characteristics of gated deliveries were compared with non-gated deliveries. The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries. The beam output variation of gated electron beam was less than 0.6 % for all electron energies except for 16 MeV (1.4 %). Based on the results of this study, it can be concluded that Varian CL2100 CD is well suitable for gated delivery of non-dynamic electron beams.

No MeSH data available.