"Biological optimization" (BIOP) means planning treatments using (radio)biological criteria and models, that is, tumour control probability and normal-tissue complication probability. Four different levels of BIOP are identified: Level I is "isotoxic" individualization of prescription dose D(presc) at fixed fraction number. D(presc) is varied to keep the NTCP of the organ at risk constant. Sign...

The imaging revolution with Ultrasound, Computed Tomography, and Magnetic Resonance Imaging entered the world of treatment planning in external beam radiation therapy in the 80ies and 90ies, step by step (9). With the support of modern computer technology, this has led to sophisticated, widespread, 3D sectional image based treatment planning, that nowadays increasingly forms an essential integr...

This article aims at presenting in a didactic way, dosimetry concepts and methods that are relevant for radio-embolization of the liver with 90 Y-microspheres. The application medical internal radiation dose formalism to is introduced. enables simplified dosimetry, where absorbed given tissue depends on only its mass initial activity. applied single-compartment method, partition model, liver, t...

AIM To create a presentation method of TCP and NTCP distributions calculated based on dose distribution for a selected CT slice. MATERIALS AND METHODS Three 24-bit colour maps - of dose distribution, delineated structures and CT information - were converted into m-by-n-by-3 data arrays, containing intensities of red, green, and blue colour components for each pixel. All calculations were perf...

PURPOSE To develop normal tissue complication probability (NTCP) model with least absolute shrinkage and selection operator (LASSO) to analyze dose-volume effects that influence the incidence of acute diarrhea among gynecological patients with/without prior abdominal surgery. METHODS AND MATERIALS Ninety-five patients receiving gynecologic radiotherapy (RT) were enrolled. The endpoint was def...

PURPOSE To calculate the normal tissue complication probability (NTCP) of late radiation effects on the rectum and bladder from repetitive CT scans during fractionated high-dose-rate brachytherapy (HDRB) and external beam radiotherapy (EBRT) of the uterine cervix and compare the NTCP with the clinical frequency of late effects. METHODS AND MATERIALS Fourteen patients with cancer of the uterin...

Radiation quality indices (QI), tumor control probability (TCP), and normal tissue complication probability(NTCP) were evaluated for ideal single and double plane HDR interstitial implants. In the analysis, geometrically-optimized at volume (GOV) treatment plans were generated for different values of inter-source-spacing (ISS) within the catheter, inter-catheter-spacing (ICS), and inter-plane-s...

OBJECTIVE To develop a similar-case-based optimization method for beam arrangements in lung stereotactic body radiotherapy (SBRT) to assist treatment planners. METHODS First, cases that are similar to an objective case were automatically selected based on geometrical features related to a planning target volume (PTV) location, PTV shape, lung size, and spinal cord position. Second, initial be...

Variation in the relative biological effectiveness (RBE) within the irradiation field of a carbon beam makes carbon-ion radiotherapy unique and advantageous in delivering the therapeutic dose to a deep-seated tumor, while sparing surrounding normal tissues. However, it is crucial to consider the RBE, not only in designing the dose distribution during treatment planning, but also in analyzing th...