TY - JOUR
T1 - A quality control model that uses PTV-rectal distances to predict the lowest achievable rectum dose, improves IMRT planning for patients with prostate cancer
AU - Wang, Yibing
AU - Zolnay, Andras
AU - Incrocci, Luca
AU - Joosten, Hans
AU - McNutt, Todd
AU - Heijmen, Ben
AU - Petit, Steven
PY - 2013/6
Y1 - 2013/6
N2 - Background and purpose To predict the lowest achievable rectum D35 for quality assurance of IMRT plans of prostate cancer patients. Materials and methods For each of 24 patients from a database of 47 previously treated patients, the anatomy was compared to the anatomies of the other 46 to predict the minimal achievable rectum D35. The 24 patients were then replanned to obtain maximally reduced rectum D35. Next, the newly derived plans were added to the database to replace the original clinical plans, and new predictions of the lowest achievable rectum D35 were made. Results After replanning, the rectum D35 reduced by 9.3 Gy ± 6.1 (average ± 1 SD; p < 0.001) compared to the original plan. The first predictions of the rectum D35 were 4.8 Gy ± 4.2 (average ± 1 SD; p < 0.001) too high when evaluated with the new plans. After updating the database, the replanned and newly predicted rectum D35 agreed within 0.1 Gy ± 2.8 (average ± 1 SD; p = 0.89). The doses to the bladder, anus and femoral heads did not increase compared to the original plans. Conclusions For individual prostate patients, the lowest achievable rectum D35 in IMRT planning can be accurately predicted from dose distributions of previously treated patients by quantitative comparison of patient anatomies. These predictions can be used to quantitatively assess the quality of IMRT plans.
AB - Background and purpose To predict the lowest achievable rectum D35 for quality assurance of IMRT plans of prostate cancer patients. Materials and methods For each of 24 patients from a database of 47 previously treated patients, the anatomy was compared to the anatomies of the other 46 to predict the minimal achievable rectum D35. The 24 patients were then replanned to obtain maximally reduced rectum D35. Next, the newly derived plans were added to the database to replace the original clinical plans, and new predictions of the lowest achievable rectum D35 were made. Results After replanning, the rectum D35 reduced by 9.3 Gy ± 6.1 (average ± 1 SD; p < 0.001) compared to the original plan. The first predictions of the rectum D35 were 4.8 Gy ± 4.2 (average ± 1 SD; p < 0.001) too high when evaluated with the new plans. After updating the database, the replanned and newly predicted rectum D35 agreed within 0.1 Gy ± 2.8 (average ± 1 SD; p = 0.89). The doses to the bladder, anus and femoral heads did not increase compared to the original plans. Conclusions For individual prostate patients, the lowest achievable rectum D35 in IMRT planning can be accurately predicted from dose distributions of previously treated patients by quantitative comparison of patient anatomies. These predictions can be used to quantitatively assess the quality of IMRT plans.
KW - Intensity modulated radiotherapy (IMRT)
KW - Overlap volume histogram (OVH)
KW - Prostate cancer
KW - Quantitative treatment plan evaluation
KW - Treatment plan assessment
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U2 - 10.1016/j.radonc.2013.05.032
DO - 10.1016/j.radonc.2013.05.032
M3 - Article
C2 - 23830193
AN - SCOPUS:84881476727
SN - 0167-8140
VL - 107
SP - 352
EP - 357
JO - Radiotherapy and Oncology
JF - Radiotherapy and Oncology
IS - 3
ER -