Tumor motion in lung cancers: An overview of four-dimensional radiotherapy treatment of lung cancers

Abstract

Most modern radiotherapy centers have adopted contouring based treatment. Sparing of the normal structures has been made more achievable than ever before by use of technologies such as Intensity Modulated Radiotherapy (IMRT) and Image guided radiotherapy (IGRT). However, unlike, sites such as brain or head neck, thorax is a site in active motion, mostly contributed by patient's respiratory movement. 4 D radiotherapy, that addresses the issues of motion in thoracic tumours answers this critical question. The present article outlines the scope of need for 4 D radiotherapy and discusses the options available for 4 D treatments of cancer patients.

Clinical experience of volumetric‐modulated flattening filter free stereotactic body radiation therapy of lesions in the lung with deep inspiration breath‐hold

“…Treatment of moving targets is challenging, and the movements can also cause geometrical distortions in the computed tomography (CT) images obtained for treatment planning. 7 Traditionally, large margins have been applied to account for lesion motion, but the adoption of fourdimensional CT (4DCT) has recently improved target delineation owing to its ability to provide information on lesion movement. 8 4DCT in free-breathing (FB) mode is now recommended in guidelines and ensures coverage of the whole tumor in each position during the breathing cycle.…”

“…found that lesions in the lower lobe, close to the diaphragm, move 12 ± 2 mm in the craniocaudal direction as a result of respiratory motion. Treatment of moving targets is challenging, and the movements can also cause geometrical distortions in the computed tomography (CT) images obtained for treatment planning 7 . Traditionally, large margins have been applied to account for lesion motion, but the adoption of four‐dimensional CT (4DCT) has recently improved target delineation owing to its ability to provide information on lesion movement 8 .…”