Dosimetric Evaluation of ۴ Field Three-Dimensional Conformal Radiation Therapy and ۷ Field Intensity Modulated Radiation Therapy in Esophageal Cancer Treated with Definitive Chemoradiation

Background: The present study aimed to evaluate dosimetrically and correlate the lung and heart dose volume histogram (DVH) of the ۴ field three-dimensional conformal radiotherapy (۳DCRT) with ۷ field intensity modulated radiotherapy (IMRT) in patients with oesophageal cancers.Method: This retrospective dosimetric study considered ۲۰ oesophagus cancer patients treated with definitive chemoradiation with IMRT technique. In the ۷ field IMRT technique, the first phase delivered a dose of ۳۶Gy/۱۸fr followed by ۱۸Gy/۹fr in two weeks in the second phase. In the ۳DCRT technique, the first phase was planned with ۴ field technique with two parallel opposed and two posterior oblique fields, followed by the ۳ field technique in the second phase. The assessments of the techniques were performed using differential DVH analysis of the right and left lungs, heart, and the spinal cord. The values of the mean dose, V۲۰ (volume receiving ۲۰ Gy), and V۳۰ (volume receiving ۳۰ Gy) were assessed for any correlations.Results: The DVH of V۲۰ in IMRT showed ۵% less lung volume irradiation compared with the ۳DCRT plans and over ۲۰% less V۳۰ for irradiated heart volume. The study demonstrated a statistical advantage of using ۷ field IMRT over ۴ field ۳DCRT in reducing the mean percentage dose to both lungs, heart, and spinal cord.Conclusion: ۷ field IMRT is superior to ۴ field ۳DCRT plans in significantly reducing the average percentage of irradiated volume of both the lung and heart in esophageal cancer radiation therapy.

کلیدواژه ها:

Esophageal neoplasms ، Radiotherapy ، Conformal ، Intensity-modulated ، Radiation dosimetry ، Heart