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The purpose of the present study is to develop patient speciﬁc unbiased quality control (QC) models for high dose rate (HDR) brachytherapy plans. The proposed models are based on the stochastic frontier analysis formalism, a method of economic modeling. They act as a QC tool by predicting before the treatment planning process starts, the dosimetric coverage achievable for a HDR brachytherapy prostate plan. The geometric parameters considered in developing the models were: patient clinical target volume (CTV), organs at risk (OAR) volume, the bidirectional Hausdorff distance between CTV and OARs, and a fourth parameter measuring the catheters degree of non-parallelism within the target volume. Dosimetry parameters of interest are V<sub>100</sub> for the CTV, V<sub>75 </sub>(bladder, rectum) and D<sub>10</sub> (urethra). Results show that the built models can provide valuable information on the personalization of the optimization process based on the patient geometric parameters. The impact on the quality plan due to the planner's experience variability and judgment can be reduced by using those models, since the planner will attempt to achieve dosimetric parameters predicted by the models. Furthermore, the models provide information on the better trade-oﬀ between the target volume coverage and OARs sparing that can be achieved, regardless of the planner's experience; the latter being achieved by moving each plan at least around their respective frontier for V<sub>100</sub>, V<sub>75</sub> and D<sub>10</sub> . The shortfall of the dosimetric parameters values computed by the treatment planning system (TPS) from those predicted by the models for a proportion of plans in the dataset reveals that optimized plans from a TPS, even clinically acceptable, are not necessarily the best that could be achieved. These represent 83% of plans in the training set for the target volume coverage (V<sub>100</sub>), ~50% for the bladder (V<sub>75</sub>) and ~72% for the urethra (D<sub>10</sub>).
This article was published in the following journal.
Name: Physics in medicine and biology
Stochastic frontier analysis is used as a novel knowledge-based technique in order to develop a predictive model of dosimetric features from signicant geometric parameters describing a patient morphol...
Rapid technological advances in high-dose-rate brachytherapy have led to a requirement for greater accuracy in treatment planning system calculations and in the verification of dose distributions. In ...
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A treatment schedule in which the total dose of radiation is divided into large doses.
Initial drug treatment designed to bring about REMISSION INDUCTION. It is typically a short-term and high-dose drug treatment that is followed by CONSOLIDATION CHEMOTHERAPY and then MAINTENANCE CHEMOTHERAPY.
The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.
The amount of radiation energy that is deposited in a unit mass of material, such as tissues of plants or animal. In RADIOTHERAPY, radiation dosage is expressed in gray units (Gy). In RADIOLOGIC HEALTH, the dosage is expressed by the product of absorbed dose (Gy) and quality factor (a function of linear energy transfer), and is called radiation dose equivalent in sievert units (Sv).
Semisynthetic thienamycin that has a wide spectrum of antibacterial activity against gram-negative and gram-positive aerobic and anaerobic bacteria, including many multiresistant strains. It is stable to beta-lactamases. Clinical studies have demonstrated high efficacy in the treatment of infections of various body systems. Its effectiveness is enhanced when it is administered in combination with CILASTATIN, a renal dipeptidase inhibitor.
Benign Prostatic Hyperplasia (BPH)
An enlarged prostate (benign prostatic enlargement (BPE) or benign prostatic hyperplasia (BPH)) is common in men after the age of about 50. Having an enlarged prostate does not mean you have cancer. In some cases, an enlarged prostate can cause the ...
Non-invasive bladder cancer is a cancer that is only in the inner lining of the bladder. Invasive bladder cancer is cancer that has spread into the deeper walls of the bladder. When the cancer has spread outside the bladder to other parts of the body, th...