What is contouring in radiotherapy?

Introduction. Contour delineation is a critical process in treatment planning because it involves outlining tumor (or areas at risk of microscopic disease) as well as nearby organs at risk (OARs) to guide radiation therapy plans that optimize tumor control and reduce radiation toxicity.

What is contouring imaging?

In most cases, contouring is carried out manually by a specialist. Digital images, obtained from modalities such as CT or MRI, are used to view and locate the tumor. The doctor then marks the perimeter of the cancerous tissue on each image. However, the accuracy of the perimeter markings varies from doctor to doctor.

What is OAR contouring?

Contouring (segmentation) of Organs at Risk (OARs) in medical images is required for accurate radiation therapy (RT) planning. In current clinical practice, OAR contouring is performed with low levels of automation.

How do you contour your spinal cord?

The visible true spinal cord should be contoured from the foramen magnum (the level of the odontoid process of the axis) to 2 cm below the inferior edge of the head of the collarbone. The whole parotid gland should be outlined, including the external carotid artery [11] and the region within CTV, but not the GTV.

What is the purpose of a therapeutic contour?

The accurate contour delineation of the target and/or organs at risk (OAR) is essential in treatment planning for image‐guided radiation therapy (IGRT). Although many automatic contour delineation approaches have been proposed, few of them can fulfill the necessities of applications in terms of accuracy and efficiency.

What is auto contouring?

Autocontouring automatically delineates organs at risk, taking away the manual need to draw around these organs. This task is a critical step in preparing a patient for radiation therapy to ensure that healthy organs surrounding the tumor are spared from radiation to improve patient outcomes.

How do you contour cauda equina?

For the cauda equina, we contour the thecal sac with 6-mm cranial and caudal margins as well. We limit the spinal cord to a maximum dose of <14 Gy and limit 10 % of the cord to 10 Gy or more. For the cauda equina, we limit the maximum dose to <16 Gy and limit 10 % of the cauda to 12 Gy or more (Figs. 3, 4, and 5).

Which method of automated contouring is more efficient?

Fully automatic contouring is potentially the most time efficient as it is designed to have little involvement of the physician.

What nerves are in the cauda equina?

A group of nerve roots that travel down from the spinal cord and the conus medullaris is called the cauda equina. The cauda equina contains nerve roots from L2 in the lumbar spine to Co1 in the coccygeal (tail bone end) spine.

What is the difference between conus medullaris and cauda equina?

The most distal bulbous part of the spinal cord is called the conus medullaris, and its tapering end continues as the filum terminale. Distal to this end of the spinal cord is a collection of nerve roots, which are horsetail-like in appearance and hence called the cauda equina (Latin for horse’s tail).