Clinical Aspects of Treatment Planning

Abstract

The goal of treatment planning in image-guided brachytherapy (BT) is to widen the therapeutic window, i.e., to obtain the best possible chance for an uncomplicated cure of the patient [1] by optimizing the organization and delivery of the treatment. If a medical compromise has to be accepted it is vital to have maximal information about the consequences of any decisions taken during the treatment planning process. From quantitative radiobiology [2] and clinical experience [3,4] we know that the dose-response curves for many organs at risk (OAR) in the pelvis are almost as steep as the dose fall-off curve of BT, implying that we may often balance on the knife's edge between success and failure in our attempt to selectively deliver a high curative dose to the tumor.Over decades of traditional X-ray-based two-dimensional BT for gynecological cancer, invaluable experience has been gained in treatment planning [4][5][6][7][8]. With the advent of image-based BT, new volumetric (3D) and temporal (4D) information has deepened our understanding of BT thus far [9][10][11][12][13][14][15][16][17][18] but also presents us with new medical challenges and concepts that must be understood and interpreted correctly to reap the potential benefit of image-based BT treatment planning [19].

Dosimetric evaluation of tandem-based cervical high-dose-rate brachytherapy treatment planning using American Brachytherapy Society 2011 recommendations

“…For large tumours Point A can fall inside the HR-CTV and receive Tandem-based cervical HDR brachytherapy treatment very high dose, whereas for smaller tumours it can be positioned outside the HR-CTV and receive correspondingly lower dose. Similar findings were observed by Lindegaard et al, 16 who studied 3D/conformal treatment plans from 72 patients with locally advanced cervical cancer and also evaluated D 90 as a function of HR-CTV. They also identified that D 90 decreases with increasing HR-CTV.…”