Details

Autor(en) / Beteiligte

• Andreozzi, Jacqueline M.
• Zhang, Rongxiao
• Glaser, Adam K.
• Jarvis, Lesley A.
• Pogue, Brian W.
• Gladstone, David J.

Titel

Camera selection for real‐time in vivo radiation treatment verification systems using Cherenkov imaging

Ist Teil von

• Medical physics (Lancaster), 2015-02, Vol.42 (2), p.994-1004

Ort / Verlag

United States: American Association of Physicists in Medicine

Erscheinungsjahr

2015

Link zum Volltext

Quelle

Wiley(RISS)

Beschreibungen/Notizen

• Purpose: To identify achievable camera performance and hardware needs in a clinical Cherenkov imaging system for real‐time, in vivo monitoring of the surface beam profile on patients, as novel visual information, documentation, and possible treatment verification for clinicians. Methods: Complementary metal‐oxide‐semiconductor (CMOS), charge‐coupled device (CCD), intensified charge‐coupled device (ICCD), and electron multiplying‐intensified charge coupled device (EM‐ICCD) cameras were investigated to determine Cherenkov imaging performance in a clinical radiotherapy setting, with one emphasis on the maximum supportable frame rate. Where possible, the image intensifier was synchronized using a pulse signal from the Linac in order to image with room lighting conditions comparable to patient treatment scenarios. A solid water phantom irradiated with a 6 MV photon beam was imaged by the cameras to evaluate the maximum frame rate for adequate Cherenkov detection. Adequate detection was defined as an average electron count in the background‐subtracted Cherenkov image region of interest in excess of 0.5% (327 counts) of the 16‐bit maximum electron count value. Additionally, an ICCD and an EM‐ICCD were each used clinically to image two patients undergoing whole‐breast radiotherapy to compare clinical advantages and limitations of each system. Results: Intensifier‐coupled cameras were required for imaging Cherenkov emission on the phantom surface with ambient room lighting; standalone CMOS and CCD cameras were not viable. The EM‐ICCD was able to collect images from a single Linac pulse delivering less than 0.05 cGy of dose at 30 frames/s (fps) and pixel resolution of 512 × 512, compared to an ICCD which was limited to 4.7 fps at 1024 × 1024 resolution. An intensifier with higher quantum efficiency at the entrance photocathode in the red wavelengths [30% quantum efficiency (QE) vs previous 19%] promises at least 8.6 fps at a resolution of 1024 × 1024 and lower monetary cost than the EM‐ICCD. Conclusions: The ICCD with an intensifier better optimized for red wavelengths was found to provide the best potential for real‐time display (at least 8.6 fps) of radiation dose on the skin during treatment at a resolution of 1024 × 1024.