Properties of a commercial PTW-60019 synthetic diamond detector for the dosimetry of small radiotherapy beams.

A CVD based radiation detector has recently become commercially available from the manufacturer PTW-Freiburg (Germany). This detector has a sensitive volume of 0.004 mm(3), a nominal sensitivity of 1 nC Gy(-1) and operates at 0 V.

Effect of dosimeter type for commissioning small photon beams on calculated dose distribution in stereotactic radiosurgery.

Purpose: To assess the impact of the detector used to commission small photon beams on the calculated dose distribution in stereotactic radiosurgery (SRS).

Methods: In this study, six types of detectors were used to characterize small photon beams: three diodes [a silicon stereotactic field diode SFD, a silicon diode SRS, and a silicon diode E], an ionization chamber CC01, and two types of radiochromic film models EBT and EBT2. These detectors were used to characterize circular collimated beams that were generated by a Novalis linear accelerator.

Dosimetry for small fields in stereotactic radiosurgery using gafchromic MD-V2-55 film, TLD-100 and alanine dosimeters.

This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK) and a modified linear accelerator (linac) for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55), alanine and thermoluminescent (TLD-100) dosimeters and compared with conventional dosimetry systems.

Poor drug distribution as a possible explanation for the results of the PRECISE trial.

Object: Convection-enhanced delivery (CED) is a novel intracerebral drug delivery technique with considerable promise for delivering therapeutic agents throughout the CNS. Despite this promise, Phase III clinical trials employing CED have failed to meet clinical end points. Although this may be due to inactive agents or a failure to rigorously validate drug targets, the authors have previously demonstrated that catheter positioning plays a major role in drug distribution using this technique.

Clinical utility of a patient-specific algorithm for simulating intracerebral drug infusions.

Convection-enhanced delivery (CED) is a novel drug delivery technique that uses positive infusion pressure to deliver therapeutic agents directly into the interstitial spaces of the brain. Despite the promise of CED, clinical trials have demonstrated that target-tissue anatomy and patient-specific physiology play a major role in drug distribution using this technique. In this study, we retrospectively tested the ability of a software algorithm using MR diffusion tensor imaging to predict patient-specific drug distributions by CED.