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Practical and clinical considerations in Cobalt-60 tomotherapy.

Joshi CP, Dhanesar S, Darko J, Kerr A, Vidyasagar PB, Schreiner LJ - J Med Phys (2009)

Bottom Line: The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX).The EGSnrc/BEAMnrc Monte Carlo (MC) code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data.A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes) and OARs (spinal cord in HandN case, and rectum in prostate case).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics, Cancer Centre of Southeastern Ontario (CCSEO), Kingston, ON, Canada.

ABSTRACT
Cobalt-60 (Co-60) based radiation therapy continues to play a significant role in not only developing countries, where access to radiation therapy is extremely limited, but also in industrialized countries. Howver, technology has to be developed to accommodate modern techniques, including image guided and adaptive radiation therapy (IGART). In this paper we describe some of the practical and clinical considerations for Co-60 based tomotherapy by comparing Co-60 and 6 MV linac-based tomotherapy plans for a head and neck (HandN) cancer and a prostate cancer case. The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX). The EGSnrc/BEAMnrc Monte Carlo (MC) code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data. An in-house inverse treatment planning program was then used to generate optimized tomotherapy dose distributions for the H and N and prostate cases. The dose distributions, cumulative dose area histograms (DAHs) and dose difference maps were used to evaluate and compare Co-60 and 6 MV based tomotherapy plans. A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes) and OARs (spinal cord in HandN case, and rectum in prostate case).

No MeSH data available.


Related in: MedlinePlus

Left: Cumulative dose area histograms for Co-60 and 6 MV linac based tomotherapy. Right: Dose difference map of Co-60 plan and 6 MV linac plan. In the dose difference map the yellow and red represent the regions where Co-60 is giving more dose than 6 MV and the blue regions represent the regions where 6 MV is giving more dose
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Figure 0004: Left: Cumulative dose area histograms for Co-60 and 6 MV linac based tomotherapy. Right: Dose difference map of Co-60 plan and 6 MV linac plan. In the dose difference map the yellow and red represent the regions where Co-60 is giving more dose than 6 MV and the blue regions represent the regions where 6 MV is giving more dose

Mentions: The cumulative dose area histograms in Figure 4, representing a quantitative analysis of the plans, show that both Co-60 and 6 MV linac based tomotherapy give similar dose to the prostate. Although in the Co-60 plan the dose to the body and rectum is slightly more in low dose regions than the 6 MV plan, the dose to these regions is within the clinically acceptable dose limits. This dose difference depends on beam energy, total number of beams as well as the optimization parameters. The difference will potentially become smaller if total number of beams is increased. In this study only 21 gantry angles were used while a typical pelvic tomotherapy treatment is likely to employ higher number of gantry angles. The dose difference map in Figure 4 shows the regions that receive relatively more or less dose when compared to that in the 6 MV plan. The positive numbers represent the regions where the dose in the Co-60 plan is higher and the negative numbers represent the regions where the dose in the 6 MV plan is higher.


Practical and clinical considerations in Cobalt-60 tomotherapy.

Joshi CP, Dhanesar S, Darko J, Kerr A, Vidyasagar PB, Schreiner LJ - J Med Phys (2009)

Left: Cumulative dose area histograms for Co-60 and 6 MV linac based tomotherapy. Right: Dose difference map of Co-60 plan and 6 MV linac plan. In the dose difference map the yellow and red represent the regions where Co-60 is giving more dose than 6 MV and the blue regions represent the regions where 6 MV is giving more dose
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2807678&req=5

Figure 0004: Left: Cumulative dose area histograms for Co-60 and 6 MV linac based tomotherapy. Right: Dose difference map of Co-60 plan and 6 MV linac plan. In the dose difference map the yellow and red represent the regions where Co-60 is giving more dose than 6 MV and the blue regions represent the regions where 6 MV is giving more dose
Mentions: The cumulative dose area histograms in Figure 4, representing a quantitative analysis of the plans, show that both Co-60 and 6 MV linac based tomotherapy give similar dose to the prostate. Although in the Co-60 plan the dose to the body and rectum is slightly more in low dose regions than the 6 MV plan, the dose to these regions is within the clinically acceptable dose limits. This dose difference depends on beam energy, total number of beams as well as the optimization parameters. The difference will potentially become smaller if total number of beams is increased. In this study only 21 gantry angles were used while a typical pelvic tomotherapy treatment is likely to employ higher number of gantry angles. The dose difference map in Figure 4 shows the regions that receive relatively more or less dose when compared to that in the 6 MV plan. The positive numbers represent the regions where the dose in the Co-60 plan is higher and the negative numbers represent the regions where the dose in the 6 MV plan is higher.

Bottom Line: The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX).The EGSnrc/BEAMnrc Monte Carlo (MC) code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data.A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes) and OARs (spinal cord in HandN case, and rectum in prostate case).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Physics, Cancer Centre of Southeastern Ontario (CCSEO), Kingston, ON, Canada.

ABSTRACT
Cobalt-60 (Co-60) based radiation therapy continues to play a significant role in not only developing countries, where access to radiation therapy is extremely limited, but also in industrialized countries. Howver, technology has to be developed to accommodate modern techniques, including image guided and adaptive radiation therapy (IGART). In this paper we describe some of the practical and clinical considerations for Co-60 based tomotherapy by comparing Co-60 and 6 MV linac-based tomotherapy plans for a head and neck (HandN) cancer and a prostate cancer case. The tomotherapy IMRT plans were obtained by modeling a MIMiC binary multi-leaf collimator attached to a Theratron-780c Co-60 unit and a 6 MV linear accelerator (CL2100EX). The EGSnrc/BEAMnrc Monte Carlo (MC) code was used for the modeling of the treatment units with the MIMiC collimator and EGSnrc/DOSXYZnrc code was used for beamlet dose data. An in-house inverse treatment planning program was then used to generate optimized tomotherapy dose distributions for the H and N and prostate cases. The dose distributions, cumulative dose area histograms (DAHs) and dose difference maps were used to evaluate and compare Co-60 and 6 MV based tomotherapy plans. A quantitative analysis of the dose distributions and dose-volume histograms shows that both Co-60 and 6 MV plans achieve the plan objectives for the targets (CTV and nodes) and OARs (spinal cord in HandN case, and rectum in prostate case).

No MeSH data available.


Related in: MedlinePlus