Intensity modulated radiotherapy versus volumetric modulated arc therapy in breast cancer: A comparative dosimetric analysis

Abstract

Purpose: Intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) has the capacity to optimize the dose distribution. We analyzed the dosimetric differences of plans in treatment planning system (TPS) between VMAT and IMRT in treating breast cancer. Methods: Fourteen patients were simulated, planned, and treated with VMAT using single, double or partial arcs. IMRT treatments were generated using 4 to 5 tangential IMRT fields for the same patients. All treatment plans were planned for 50 Gy in 25 fractions. The VMAT and IMRT plans were compared using the planning target volume (PTV) dose and doses to the other organs at risk (OARs). Results: For the PTV, comparable minimum, mean, maximum, median, and modal dose as well equivalent sphere diameter of the structure (Equis) were observed between VMAT and IMRT plans and found that these values were significantly equal in both techniques. The right lung mean and modal doses were considerably higher in VMAT plans while maximum value was considerably lower when compared with IMRT plans. The left lung mean and modal doses were higher with VMAT while maximum doses were higher in IMRT plans. The mean dose to the heart and maximum dose to the spinal cord was lower with IMRT. The mean dose to the body was higher in VMAT plans while the maximum dose was higher in IMRT plans. Conclusion: Four field tangential IMRT delivered comparable PTV dose with generally less dose to normal tissues in our breast cancer treatment study. The IMRT plans typically had more favourable dose characteristics to the lung, heart, and spinal cord and body dose when compared with VMAT. The only minor advantage of VMAT for breast cases was slightly better PTV coverage.

Yoğunluk ayarlı radyoterapi yapılan meme kanseri hastalarında, tiroid bezinde ikincil malignite gelişme riski tahmini

“…2 Yoğunluk ayarlı radyoterapi (Intensity modulated radiotherapy-IMRT) tekniği, meme radyoterapisinde hedef hacme istenen dozu veren ve kritik organ risklerini (OaR) mümkün olduğunca azaltan bir ışınlama tekniğidir. 3 IMRT gibi gelişmiş RT teknikleri ile kritik organ dozları mümkün olduğunca azaltılabilmesine rağmen, meme RT'si sonrası uzun dönem sağ kalımlarda tiroid bezi, karşı meme ve akciğerlerde radyasyona bağlı ikincil malignite gelişebilmektedir. 4,5 Son zamanlarda ulusal ve uluslararası çalışma grupları düşük LET'li (Linear energy transfer-lineer enerji transferi) radyasyonların düşük seviyeli ışınlamalarında tahmini kanser riski için modeller geliştirmişlerdir.…”

The Composite Planning Technique in Left Sided Breast Cancer Radiotherapy: A Dosimetric Study

“…In breast cancer radiation planning, VMAT results in an increased low dose radiation spillage to lung, heart and contralateral breast as compared to conventional plans (27). TFIF plans on the other hand have shown to reduce the number of MUs and treatment time but with inferior PTV coverage as compared to VMAT.…”

Development of radiation therapy for breast cancer

“…По данным K. Muralidhar и соавт. [67], при использовании планов IMRT с 4-5 тангенциальными полями дозное распределении в PTV будет сопоставимо с методикой VMAT, но дозная нагрузка на окружающие ткани, спинной мозг и легкие будет несколько меньше.…”