RESUMO
BACKGROUND: This study aimed to develop fully automated script-based radiotherapy treatment plans for cervical cancer patients, and evaluate them against clinically accepted plans, as validation before clinical implementation. MATERIAL AND METHODS: In this retrospective planning study, treatment plans for 25 locally advanced cervical cancer (LACC) patients with up to three dose levels were included. Fully automated plans were created using an in-house developed Python script in RayStation, and compared to clinically accepted manually made plans. Quantitatively, relevant dose statistics were compared, and average dose volume histograms (DVHs) were analyzed. Qualitatively, a blinded plan comparison was conducted between the clinical and automatic plans. The accuracy of treatment plan delivery was verified with the Delta4 Phantom+. RESULTS: The quantitative evaluation showed that target coverage was acceptable for all the automatic and clinical plans. The automatic plans were significantly more conformal than the clinical plans; median of 1.03 vs. 1.12. Mean doses to almost all organs at risk (OARs) were reduced in the automatic plans, with a median reduction of between 0.6 Gy and 1.9 Gy. In the blinded plan comparison, the automatic plans were the preferred plans or of equal quality as the clinical plans in 99% of the cases. In addition, plan delivery was excellent, with a mean gamma passing rate of 99.8%. Complete script-based plans were generated in 30-45 min; about four to ten times faster than manually made plans. CONCLUSION: The automatic plans had acceptable target coverage, lower doses to almost all OARs, more conformal dose distributions, and were predominantly preferred by the clinicians. Based on these results, our institution has implemented the script for clinical use.
Assuntos
Radioterapia de Intensidade Modulada , Neoplasias do Colo do Útero , Feminino , Humanos , Radioterapia de Intensidade Modulada/métodos , Neoplasias do Colo do Útero/radioterapia , Estudos Retrospectivos , Planejamento da Radioterapia Assistida por Computador/métodos , Dosagem Radioterapêutica , Órgãos em RiscoRESUMO
PURPOSE: To investigate the isodose surface volumes (ISVs) for 85, 75 and 60â¯Gy EQD2 for locally advanced cervix cancer patients. MATERIALS AND METHODS: 1201 patients accrued in the EMBRACE I study were analysed. External beam radiotherapy (EBRT) with concomitant chemotherapy was followed by MR based image-guided adaptive brachytherapy (MR-IGABT). ISVs were calculated using a predictive model based on Total Reference Air Kerma and compared to Point A-standard loading systems. Influence of fractionation schemes and dose rates was evaluated through comparison of ISVs for α/ß 10â¯Gy and 3â¯Gy. RESULTS: Median V85â¯Gy, V75â¯Gy and V60â¯Gy EQD210 were 72â¯cm3, 100â¯cm3 and 233â¯cm3, respectively. Median V85â¯Gy EQD210 was 23% smaller than in standard 85â¯Gy prescription to Point A. For small (<25â¯cm3), intermediate (25-35â¯cm3) and large (>35â¯cm3) CTVHR volumes, the V85â¯Gy was 57â¯cm3, 70â¯cm3 and 89â¯cm3, respectively. In 38% of EMBRACE patients the V85â¯Gy was similar to standard plans with 75-85â¯Gy to Point A. 41% of patients had V85â¯Gy smaller than standard plans receiving 75â¯Gy at Point A, while 21% of patients had V85â¯Gy larger than standard plans receiving 85â¯Gy at Point A. CONCLUSIONS: MR-IGABT and individualized dose prescription during EMBRACE I resulted in improved target dose coverage and decreased ISVs compared to standard plans used with classical Point A based brachytherapy. The ISVs depended strongly on CTVHR volume which demonstrates that dose adaptation was performed per individual tumour size and response during EBRT.