Intensity modulated radiation therapy versus three‐dimensional conformal radiation therapy for the treatment of high grade glioma: a dosimetric comparison

Abstract

The present study compared the dosimetry of intensity‐modulated radiation therapy (IMRT) and three‐dimensional conformal radiation therapy (3D‐CRT) techniques in patients treated for high‐grade glioma. A total of 20 patients underwent computed tomography treatment planning in conjunction with magnetic resonance imaging fusion. Prescription dose and normal‐tissue constraints were identical for the 3D‐CRT and IMRT plans. The prescribed dose was 59.4 Gy delivered at 1.8 Gy per fraction using 4 – 10 MV photons. Normal‐tissue dose constraints were 50 – 54 Gy for the optic chiasm and nerves, and 55 – 60 Gy for the brainstem.The IMRT plan yielded superior target coverage as compared with the 3D‐CRT plan. Specifically, minimum and mean planning target volume cone down doses were 54.52 Gy and 61.74 Gy for IMRT and 50.56 Gy and 60.06 Gy for 3D‐CRT (p≤0.01). The IMRT plan reduced the percent volume of brainstem receiving a dose greater than 45 Gy by 31% (p=0.004) and the percent volume of brain receiving a dose greater than 18 Gy, 24 Gy, and 45 Gy by 10% (p=0.059), 14% (p=0.015), and 40% (p≤0.0001) respectively. With IMRT, the percent volume of optic chiasm receiving more than 45 Gy was also reduced by 30.40% (p=0.047). As compared with 3D‐CRT, IMRT significantly increased the tumor control probability (p≤0.005) and lowered the normal‐tissue complication probability for brain and brainstem (p<0.033).Intensity‐modulated radiation therapy improved target coverage and reduced radiation dose to the brain, brainstem, and optic chiasm. With the availability of new cancer imaging tools and more effective systemic agents, IMRT may be used to intensify tumor doses while minimizing toxicity, therefore potentially improving outcomes in patients with high‐grade glioma.PACs number: 87.53 Tf

Concurrent chemoradiotherapy with weekly nedaplatin versus radiotherapy alone in elderly patients with non-small-cell lung cancer

“…The advent of IMRT enables dose distribution that is more conformal to tumoral well as gives permission to dose escalation to target volumes while sparing normal structures [8,9]. Nevertheless, the appearance of distant metastases affects the prognosis of patients.…”

Dosimetric comparison of three dimensional conformal radiotherapy and intensity modulated radiotherapy in high grade gliomas

“…Similarly, MacDonald et al, in their study [10] compared 3DCRT and IMRT plans for 20 patients using a phased plan, initially delivering 45 Gy to the whole PTV, followed by boost to 59.4 Gy to the coned-down PTV (GTV with margin). Dosimetric analysis revealed superior target coverage with IMRT with statistically significant increased maximum and minimum PTV doses as well as significantly increased D100.…”

The Helical Tomotherapy Experience on Radiotherapy of Glioblastoma Multiforme

“…Several studies have reported employing intensity modulated radiotherapy (IMRT) techniques that offered an advantage in terms of reducing the dose to critical normal structures and a reduced dose to the normal brain (6,7). Although these dosimetric advantages have not been translated into an improvement in reported survival in many studies, Aherne et al in their study with 31 patients reported that the combination of IMRT at standard radiation doses with TMZ can lead to an increase in median overall survival (8).…”