Dose Calculation Accuracy of AAA and AcurosXB Algorithms for Small Central and Interface Lung Lesions - Verification with Gafchromic Film Dosimetry.

Dose calculation for small field radiotherapy with heterogeneity often involves discrepancies, so that algorithms used by treatment planning systems (TPS) should be evaluated with reference to achieving optimal treatment results. Accuracy of two model based algorithms, AcurosXB (AcXB) and the analytical anisotropic algorithm (AAA) from Eclipse TPS, were here tested. Measurements are made using Gafchromic EBT3 films with indigenously generated lung phantoms irradiated with 6 MV photons.

Estimating Second Malignancy Risk in Intensity-Modulated Radiotherapy and Volumetric-Modulated Arc Therapy using a Mechanistic Radiobiological Model in Radiotherapy for Carcinoma of Left Breast.

Objectives: The aim of this study is to estimate second cancer risk (SCR) in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) using a mechanistic radiobiological model. The model also takes into account patient age at exposure and the gender-specific correction factors of SCR.

Materials And Methods: Fifty IMRT and VMAT plans were selected for the study.

Radiation-Induced Second Cancer Risk from External Beam Photon Radiotherapy for Head and Neck Cancer: Impact on in-Field and Out-of-Field Organs.

The purpose of this paper is to provide data on development of second primary cancers within or adjacent to tissue irradiated in the treatment of primary head and neck cancers using different techniques and modalities. Materials and methods: We selected five patients with HandN tumors located in base of the tongue for risk assessment. In order to examine the impact of choices of various planning techniques, numbers of beams and beam energy used in treatment plans - 7 and 9 field Intensity modulated radiotherapy (IMRT) plans using 6MV and 10 MV beam energies and a 6MV Volumetric modulated arc therapy (VMAT) plans were planned.

The effect of influence quantities and detector orientation on small-field patient-specific IMRT QA: comparison of measurements with various ionization chambers.

Intensity-modulated radiation therapy (IMRT) requires a patient-specific quality assurance (QA) program to validate the treatment plan and a high level of dosimetric accuracy in the treatment delivery. Dosimetric verification generally consists of both absolute- and relative-dose measurements in a phantom using ionization chambers. Measurements were carried out with three different ionization chambers (Scanditronix FC 65G, Exradin A18, and PTW PinPoint 31014) to assess the effects of influence quantities such as the stability, pre- and post-irradiation leakage, stem effect, polarity, and ion recombination on the IMRT point-dose verification with two different orientations.

Percentage depth dose calculation accuracy of model based algorithms in high energy photon small fields through heterogeneous media and comparison with plastic scintillator dosimetry.

Small fields smaller than 4 × 4 cm2 are used in stereotactic and conformal treatments where heterogeneity is normally present. Since dose calculation accuracy in both small fields and heterogeneity often involves more discrepancy, algorithms used by treatment planning systems (TPS) should be evaluated for achieving better treatment results. This report aims at evaluating accuracy of four model-based algorithms, X-ray Voxel Monte Carlo (XVMC) from Monaco, Superposition (SP) from CMS-Xio, AcurosXB (AXB) and analytical anisotropic algorithm (AAA) from Eclipse are tested against the measurement.

Fluorescence spectral diagnosis of malaria: a preliminary study.

Background: Malaria is the most common disease transmitted by the bite by an infected female anopheles mosquito and caused by the plasmodium parasite. It is mostly prevalent in subtropical regions receiving abundant rain and supporting copious mosquito breeding. This disease is generally detected by the microscopic examination of blood films or antigen based rapid diagnostic test.

Analysis of physical parameters and determination of inflection point for Flattening Filter Free beams in medical linear accelerator.

Background: Medical Linear accelerators manufactured without flattening filters are increasing popular in recent days. The removal of flattening filter results in increased dose rate, reduced mean energy, reduction in head leakage and lateral scattering, which have shown advantageous when used for special treatment procedures.

Aim: This study aims to analyze physical parameters of FFF beams and to determine the inflection point for standardizing the beam flatness and penumbra.

Influence of segment width on plan quality for volumetric modulated arc based stereotactic body radiotherapy.

Aim: To study the influence of segment width on plan quality for volumetric modulated arc based stereotactic body radiotherapy.

Background: The redundancy of modulation for regularly shaped small volume tumors results in creation of many small segments and an increase of monitor units, with a consequent prolongation of treatment and uncertainty in treatment delivery.

Materials And Methods: Six cases each in lung, abdomen and liver were taken for the study.