### Abstract

Purpose: Widely used for prostate cancer treatment, IMRT provides more conformal dose to target and better sparing of the critical normal structures than 3DCRT. It has been shown that the stricter constraints in IMRT planning provide better dosimetric results. The purpose of this study is to assess if the stricter constraints also produce better biological consequence by using the biological effective uniform dose (BEUD) and complication‐free tumor control probability (P_{+}). Method and Materials: The IMRT plans were created for 9 and 7 prostate cancer patients respectively with 6 MV and 18 MV photon beams, using two IMRT planning dose/volume constrains of OARs: from RTOG 0415 (RTOG) and from published data with stricter constrains (FCCC), separately. For each patient, the contours of prostate (GTV=PTV), bladder, rectum, left and right femoral heads, and penile bulb were delineated on planning CT by the same physician. The biological difference of corresponding plans was measured and compared by the BEUD (D̿) and P_{+}. Results: At the optimum dose levels of the RTOG dose constraint using 6 and 18 MV photons, the P_{+} is 61.1% for a D̿_{PTV} of 90.4 Gy and 62.6% for a D̿_{PTV} of 90.3 Gy, respectively, and the corresponding total tumor control probabilities P_{B} are 89.2% and 88.9%, whereas the total complication probabilities P_{I} are 28.1% and 26.3%, respectively. At the optimum dose levels of the stricter FCCC dose constraint using 6 and 18 MV photons, the P_{+} is 84.6% for a D̿_{PTV} of 95.4 Gy and 77% for a D̿_{PTV} of 92.8 Gy. The corresponding total tumor cation probabilities P_{B} are 95.1% and 92.8%, whereas the total complication probabilities P_{I} are 10.5% and 15.8%, respectively. Conclusion: The more stringent IMRT planning constraints leads to better radiobiological outcome for prostate cancer treatment at the same beam energy.

Original language | English (US) |
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Pages (from-to) | 3302 |

Number of pages | 1 |

Journal | Medical Physics |

Volume | 37 |

Issue number | 6 |

DOIs | |

State | Published - 2010 |

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### ASJC Scopus subject areas

- Biophysics
- Radiology Nuclear Medicine and imaging

### Cite this

*Medical Physics*,

*37*(6), 3302. https://doi.org/10.1118/1.3468899

**SU‐GG‐T‐503 : Do Stricter IMRT Planning Constraints Produce Better Radiobiological Results?** / Lei, Y.; Mavroidis, P.; Buckey, C.; Stathakis, Sotirios; Swanson, Gregory P; Papanikolaou, Nikos.

Research output: Contribution to journal › Article

*Medical Physics*, vol. 37, no. 6, pp. 3302. https://doi.org/10.1118/1.3468899

}

TY - JOUR

T1 - SU‐GG‐T‐503

T2 - Do Stricter IMRT Planning Constraints Produce Better Radiobiological Results?

AU - Lei, Y.

AU - Mavroidis, P.

AU - Buckey, C.

AU - Stathakis, Sotirios

AU - Swanson, Gregory P

AU - Papanikolaou, Nikos

PY - 2010

Y1 - 2010

N2 - Purpose: Widely used for prostate cancer treatment, IMRT provides more conformal dose to target and better sparing of the critical normal structures than 3DCRT. It has been shown that the stricter constraints in IMRT planning provide better dosimetric results. The purpose of this study is to assess if the stricter constraints also produce better biological consequence by using the biological effective uniform dose (BEUD) and complication‐free tumor control probability (P+). Method and Materials: The IMRT plans were created for 9 and 7 prostate cancer patients respectively with 6 MV and 18 MV photon beams, using two IMRT planning dose/volume constrains of OARs: from RTOG 0415 (RTOG) and from published data with stricter constrains (FCCC), separately. For each patient, the contours of prostate (GTV=PTV), bladder, rectum, left and right femoral heads, and penile bulb were delineated on planning CT by the same physician. The biological difference of corresponding plans was measured and compared by the BEUD (D̿) and P+. Results: At the optimum dose levels of the RTOG dose constraint using 6 and 18 MV photons, the P+ is 61.1% for a D̿PTV of 90.4 Gy and 62.6% for a D̿PTV of 90.3 Gy, respectively, and the corresponding total tumor control probabilities PB are 89.2% and 88.9%, whereas the total complication probabilities PI are 28.1% and 26.3%, respectively. At the optimum dose levels of the stricter FCCC dose constraint using 6 and 18 MV photons, the P+ is 84.6% for a D̿PTV of 95.4 Gy and 77% for a D̿PTV of 92.8 Gy. The corresponding total tumor cation probabilities PB are 95.1% and 92.8%, whereas the total complication probabilities PI are 10.5% and 15.8%, respectively. Conclusion: The more stringent IMRT planning constraints leads to better radiobiological outcome for prostate cancer treatment at the same beam energy.

AB - Purpose: Widely used for prostate cancer treatment, IMRT provides more conformal dose to target and better sparing of the critical normal structures than 3DCRT. It has been shown that the stricter constraints in IMRT planning provide better dosimetric results. The purpose of this study is to assess if the stricter constraints also produce better biological consequence by using the biological effective uniform dose (BEUD) and complication‐free tumor control probability (P+). Method and Materials: The IMRT plans were created for 9 and 7 prostate cancer patients respectively with 6 MV and 18 MV photon beams, using two IMRT planning dose/volume constrains of OARs: from RTOG 0415 (RTOG) and from published data with stricter constrains (FCCC), separately. For each patient, the contours of prostate (GTV=PTV), bladder, rectum, left and right femoral heads, and penile bulb were delineated on planning CT by the same physician. The biological difference of corresponding plans was measured and compared by the BEUD (D̿) and P+. Results: At the optimum dose levels of the RTOG dose constraint using 6 and 18 MV photons, the P+ is 61.1% for a D̿PTV of 90.4 Gy and 62.6% for a D̿PTV of 90.3 Gy, respectively, and the corresponding total tumor control probabilities PB are 89.2% and 88.9%, whereas the total complication probabilities PI are 28.1% and 26.3%, respectively. At the optimum dose levels of the stricter FCCC dose constraint using 6 and 18 MV photons, the P+ is 84.6% for a D̿PTV of 95.4 Gy and 77% for a D̿PTV of 92.8 Gy. The corresponding total tumor cation probabilities PB are 95.1% and 92.8%, whereas the total complication probabilities PI are 10.5% and 15.8%, respectively. Conclusion: The more stringent IMRT planning constraints leads to better radiobiological outcome for prostate cancer treatment at the same beam energy.

UR - http://www.scopus.com/inward/record.url?scp=85024780006&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85024780006&partnerID=8YFLogxK

U2 - 10.1118/1.3468899

DO - 10.1118/1.3468899

M3 - Article

AN - SCOPUS:85024780006

VL - 37

SP - 3302

JO - Medical Physics

JF - Medical Physics

SN - 0094-2405

IS - 6

ER -