Elsevier

Radiotherapy and Oncology

Volume 93, Issue 3, December 2009, Pages 593-596
Radiotherapy and Oncology

Brain tumor radiotherapy
Radiotherapy of malignant gliomas: Comparison of volumetric single arc technique (RapidArc), dynamic intensity-modulated technique and 3D conformal technique

https://doi.org/10.1016/j.radonc.2009.10.002Get rights and content

Abstract

Purpose

The analysis was designed to identify the optimal radiation technique for patients with malignant glioma.

Methods

A volumetric-modulated radiation treatment technique (RapidArc), an IMRT technique and a 3D conformal technique were calculated on computed tomograms of 14 consecutive patients with malignant glioma. The treatment plans were compared with each other using dose–volume histograms.

Results

The 3D conformal technique showed a good PTV coverage, if PTV was distant to organs at risk (OAR). If PTV was nearby OAR, the 3D technique revealed a poor PTV coverage in contrast to both intensity-modulated techniques. The conventional IMRT technique showed a slightly better PTV coverage than RapidArc. The advantages of RapidArc were a shorter treatment time, less monitor units and a small V107%.

Conclusions

If PTV is distant to OAR, the use of 3D conformal technique is sufficient. Otherwise an intensity-modulated technique should be used. RapidArc was faster than conventional IMRT and should be preferred if PTV coverage is adequate.

Section snippets

Methods and materials

Fourteen consecutive patients with malignant glioma WHO stages III–IV were included in our analysis. All patients underwent radiochemotherapy with temozolomide [12] and received a total dose of 60.0 Gy to the tumor or preoperative tumor region. All patients were positioned with a mask system (Sinmed, Reeuwijk, Denmark). Continuous 5 mm CT scans of the head were obtained with a single-slice spiral CT scanner in supine position (Somatom Balance, Siemens Medical Systems, Forchheim, Germany).

The

Results

The CI95% was slightly higher for RapidArc (0.89) relative to IMRT (0.86) but much higher than 3D conformal technique (0.63) (Table 1). Nevertheless PTV coverage was higher for IMRT (94.7%) than for RapidArc (90.5%) and 3D conformal technique (81.2%). If considering patients with PTV located distant to OAR (in this case optical nerves, chiasm and brainstem) PTV coverage for 3D conformal technique was 94.3% (50% of the analyzed patients). This decreased PTV coverage to 68.2% for patients with

Discussion

This study analyzed RapidArc, sliding window IMRT and 3D conformal technique for patients with malignant glioma.

If PTV was distant to OAR (in this case optical nerves, chiasm and brainstem), the PTV coverage was acceptable by use of 3D conformal technique (94.3% of the volume is covered by 95% of the prescribed dose). This was comparable to PTV coverage achieved by the intensity-modulated treatment technique (Table 1). The advantages of 3D conformal technique were small low-dose areas, less

Conclusions

If PTV is distant to optical nerves, chiasm and brainstem 3D conformal technique can be applied in order to have small low-dose areas, few monitor units and short delivery time accompanied with good PTV coverage. If PTV is nearby OAR intensity-modulated treatment technique should be used. If PTV coverage is acceptable, RapidArc should be favored because of the short treatment time. Otherwise conventional IMRT should be applied.

References (21)

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