In this paper, we propose a CdZnTe rotating and spinning gamma camera attached with a slit collimator. This imaging system acquires convergent planar integrals of a radioactive distribution. Two analytical image reconstruction algorithms are proposed. Preliminary phantom studies show that our small CdZnTe camera with a slit collimator outperforms a larger NaI(Tl) camera with a pinhole collimato...

PURPOSE To develop an automated beam placement technique for whole breast radiotherapy using tangential beams. We seek to find optimal parameters for tangential beams to cover the whole ipsilateral breast (WB) and minimize the dose to the organs at risk (OARs). METHODS A support vector machine (SVM) based method is proposed to determine the optimal posterior plane of the tangential beams. Rel...

Traditional external beam radiotherapy of gynecological cancer consists of a 3D, four-field-box technique. The radiation treatment area is a large region of normal tissue, with greater inhomogeneity over the treatment volume, which could benefit more with intensity-modulated radiation therapy (IMRT). This is a case report of IMRT planning for a patient with endometrial cancer. The planning targ...

UNLABELLED A dedicated stationary cardiac single-photon emission computed tomography (SPECT) system with a novel segmented slant-hole collimator has been developed. The goal of this paper is to calibrate this new imaging geometry with a point source. METHODS Unlike the commercially available dedicated cardiac SPECT systems, which are specialized and can be used only to image the heart, our pr...

UNLABELLED Myocardial perfusion imaging with SPECT remains critically important for diagnosing, assessing, and evaluating treatment of coronary artery disease. However, conventional rotational SPECT suffers from prolonged study times because of relatively low detection efficiency. We therefore have investigated a multipinhole collimator that could improve the detection efficiency in cardiac SPE...

Introduction: Image quality and accuracy of in vivo activity quantification in SPECT are affected by collimator penetration and scatter components, especially in high energy imaging. These phenomena highly depend on the collimator characteristic and photon energy. The presence of penetrated and scattered photons from collimator in SPECT images degrades spatial resolution, contr...

The aim of this study was to determine the shuttle dose for all collimator helmets (4, 8, 14 and 18 mm) of the Gamma Knife, model B, in Vienna, Austria. The additional dose accumulated during the transport of the patient in and out of the treatment position should be considered in the dose planning procedure of multicentre treatment regimens and in fractionated stereotactic Gamma Knife radiothe...

The authors have previously reported a simulation study on a novel multi-pinhole (MP) collimator that is able to provide improved angular sampling and an enlarged imaging field of view (FOV) when compared to a low-energy high-resolution parallel-hole (LEHR) collimator using a detector of equivalent size. The aim of this study was to develop a miniature single photon emission computerized tomogr...

This paper discusses the use of small pixels in a spinning CdZnTe single photon emission computed tomography (SPECT) camera that is mounted with a parallel slat collimator. In a conventional slat collimation configuration, there is a detector pixel between two adjacent collimator slats. In our design, the pixel size is halved. That is, there are two smaller pixels to replace a regular pixel bet...

The SLC final-focus system accommodates 29 fixed or adjustable collimators for machine protection and background reduction. By amplifying pulse-to-pulse orbit variations and by generating emittance growth, collimator wake fields may degrade the beam quality at the interaction point (IP). In the SLC final focus, collimator halfapertures are larger than the bunch length, so that the standard coll...