Charge-Coupled Device-Based Detector Array for Dose Quantification at Diagnostic Energies

Date(s) - 09/26/2014
2:00 pm

Ellen Gopan, PhD candidate

Radiation dosimetry measures the absorbed dose to matter after exposure to ionizing radiation.  Because even a small amount of radiation can result in serious organ complications, it is important to quantify accurately the dose that a patient will receive from any given radiation procedure before use.  The main goal of this work was to develop and evaluate a new dosimetry system, consisting of an array of plastic scintillation detectors (PSDs) coupled to an optical fiber and a charge-coupled device (CCD) camera, for use in the diagnostic radiology energy range, which will be able to quantify this added dose more rapidly, effectively and consistently.

A variety of dosimeters, such as diodes, ionization chambers, metal-oxide field-effect transistors (MOSFETs), optically stimulated luminescent dosimeters (OSLDs) and thermoluminescent dosimeters (TLDs), are available for dosimetry applications.  However, the proposed PSD array design coupled to a CCD camera for rapid and accurate dose measurements will make this dosimetry system particularly useful for multiple organ dose measurements in-phantom.  The PSD’s small size and real-time output capability, as well as its dose rate and energy independence, low cost and tissue equivalence, make it an ideal dosimeter for in-phantom as well as in vivo dose measurements.

The system was used to quantify more totally the fetal dose from computed tomography (CT), and the results compared to similar organ dose measurements in literature.  CT is often used in pregnant patients for such indications as suspected appendicitis, pulmonary embolus or trauma, most likely because of its wide availability.  Radiation dose to a fetus may result in an increased risk of fetal organ abnormalities (during organogenesis), mental retardation and increased head size, as well as increased future risk of cancer and even fetal death.