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Updated: Jun 6, 2026
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Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy
Published on: May 8, 2018
Comparison of simple and complex liver intensity modulated radiotherapy
Mark T Lee1, Thomas G Purdie, Cynthia L Eccles
1Radiation Medicine Program, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada. mark.lee@petermac.org
Radiation Oncology (London, England)
|December 1, 2010
Summary
Simplifying intensity-modulated radiotherapy (IMRT) for liver cancer by reducing segment complexity maintained tumor coverage and normal tissue protection. This approach reduced treatment delivery complexity and monitor units, though with slightly decreased dose conformity.
Area of Science:
- Radiation Oncology
- Medical Physics
Background:
- Intensity-modulated radiotherapy (IMRT) offers potential for improved liver cancer treatment plans.
- Increased modulation complexity in IMRT can introduce uncertainties and necessitate rigorous quality assurance.
Purpose of the Study:
- To assess if target coverage and normal tissue sparing can be maintained in liver cancer IMRT plans by reducing treatment complexity.
- To evaluate the impact of simplifying fluence delivery on plan quality and safety.
Main Methods:
- Developed individualized IMRT plans for 27 liver cancer patients (45 tumors) with 6 fractions.
- Systematically reduced the number of segments while ensuring 95% planning target volume (PTV) coverage and adhering to normal tissue dose constraints.
- Compared dose coverage, normal tissue toxicity risk, and conformity between baseline and simplified plans.
Main Results:
- Achieved significant reduction in segments from a median of 48 to 19 across all plans.
- Maintained equivalent dose coverage (PTVD95) and similar PTV Equivalent Uniform Dose (EUD) in simplified plans.
- Reduced monitor units (mean 1892 to 1695) but observed a decrease in dose conformity (Conformity Index 1.42 to 1.53).
Conclusions:
- Simplified liver IMRT plans successfully maintained tumor coverage and normal tissue objectives.
- Reducing IMRT complexity offers benefits in terms of reduced monitor units and delivery efficiency.
- The trade-off for simplification includes a reduction in dose conformity.
