Australia‐wide comparison of intensity modulated radiation therapy prostate plans*

Abstract

The aim of this study was to investigate the ability of Australian centres to produce high-dose intensity modulated radiation therapy (IMRT) prostate plans, and to compare the planning parameters and resultant dose distributions. Five Australian radiation therapy departments were invited to participate. Each centre received an identical 5 mm-slice CT data set complete with contours of the prostate, seminal vesicles, rectum, bladder, femoral heads and body outline. The planning team was asked to produce the best plan possible, using published Memorial Sloan-Kettering Cancer Centre prescription and dose constraints. Three centres submitted plans for evaluation. All plans covered the planning target volume adequately; however, only one plan met all the critical organ dose constraints. Although the planning parameters, beam arrangements and planning systems were different for each centre, the resulting plans were similar. In Australia, IMRT for prostate cancer is in the early stages of implementation, with routine use limited to a few centres.

Surveillance on interfacility differences in dose-prescription policy of intensity-modulated radiation therapy plans for prostate cancer

“…Creating plans of uniform quality among different institutions is difficult, even when the planning goals are indicated [15]. In the present study, although there was wide variation among the optimization parameters, even when using the same planning system, the resulting PTV doses were similar.…”

The Potential for Dose Dumping in Normal Tissues with IMRT for Pelvic and H&N Cancers

“…Some of these concerns with IMRT are: (1) integral dose to the normal tissues, 18 -22 (2) higher MUs 19 -23 , and (3) the potential for dose dumping in the normal tissues in the path of the beams. 6,9,10,11,20,24 The transition from 3DCRT to IMRT has resulted in more normal tissue receiving lower doses of radiation in patients treated with IMRT. This is mainly due to more number of beams, more MUs, and increased dose from transmission and leakage.…”

Dosimetric comparison of intensity-modulated solutions for intact prostate cancer

“…Complex computer algorithms determine how to deliver the assigned objectives through a series of nonuniform intensity beams. 2,4,5 Unfortunately, IMRT delivery spreads dose to areas of beam interjection, specifically to those areas that are not assigned objectives. 7 This phenomenon has been coined "dose dumping" by some authors.…”

“…2 To achieve this result, escalation of dose is necessary. 1,[3][4][5] Unfortunately, dose escalation can potentially end in increased complications, mainly gastrointestinal tract (GI) and genitourinary (GU). 1,3,6 Advancements such as 3-dimensional conformal radiotherapy have been shown to lower rates of GI and GU complications.…”