Computer-Controlled Delivery of 3D Conformal Radiation Treatments

Mohan, Radhe; Mageras, G.; Wu, Qiuwen

doi:10.1007/978-1-4615-5769-2_3

Cited by 4 publications

(1 citation statement)

References 24 publications

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“…In intensity‐modulated radiation therapy, the photon intensity within each field may also be modulated to attain a more homogenous target dose and greater sparing of normal tissues. Methods to deliver these intensity‐modulated treatments include using custom‐made physical compensating filters, moving the MLC leaves during treatment to modulate dynamically photon fluence and field shape (dynamic IMRT), and delivering a series of MLC‐shaped fields in rapid sequence (step‐and‐shoot IMRT) 5 …”

Section: Introductionmentioning

confidence: 99%

Use of Photon Fields With Noncoincident Isocenters to Improve Homogeneity of Dose Distribution

Pruitt

Thrall

2004

Vet Radiology Ultrasound

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To compare changes in dose distribution in irregularly shaped volumes treated using fields with noncoincident isocenters compared with fields with coincident isocenters. The hypothesis was that use of fields with noncoincident isocenters would result in improved homogeneity of dose distribution. We chose to test the hypothesis in canine nasal tumors because of the increased dorsoventral thickness of the caudal compared with the rostral nasal cavity. Computed tomography images from eight dogs with nasal tumors were selected. A tissue-contouring program was used to outline contours, including the mandible as a normal tissue structure and the planning target volume (PTV), divided into a rostral and caudal volume. A traditional computerized treatment plan consisting of two parallel-opposed fields was constructed for each dog. A second treatment plan using a third caudally located field having a different isocenter was constructed for comparison. Dose-volume histograms were generated and compared for each contoured structure in both plans. In all dogs the use of noncoincident fields resulted in increased dose to the ethmoid region through the caudal field. Minimum dose in the caudal tumor PTV increased as well. At the same time, dose delivered to the mandible, prone to develop significant side effects, was lower in all dogs with the use of noncoincident fields, as it was possible to reduce the dose delivered from the ventral field. Use of photon fields with noncoincident isocenters can improve the dose distribution in irregularly shaped volumes in comparison with fields with coincident isocenters. Improved tumor dose distribution was achieved with the addition of a smaller field having a different isocenter.

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Section: Introductionmentioning

confidence: 99%