Diffuse involvement of the pancreas in neuroendocrine tumor is a rare presentation, and its appearance on In-111 pentetreotide scan has not been reported earlier in the literature. We present the whole body images from In-111 pentetreotide scan, contrast-enhanced computed tomography images, and histopathology correlation.
Uterine leiomyomas are one of the most common tumors affecting reproductive-age women. Leiomyomas can present as an intrauterine mass or rarely as an extrauterine tumor. Depending on its location, the diagnosis of extrauterine leiomyoma can be challenging, and multiple imaging modalities may be needed for correct identification and differentiation from malignant entities. We report the case of a 48-year-old-postmenopausal female who presented with a painful left inguinal mass, which was clinically diagnosed as inguinal hernia. Ultrasound, computed tomography, magnetic resonance imaging, and percutaneous biopsy were used to characterize the mass. Surgical resection and histopathological analysis revealed the mass to be a parasitic leiomyoma, a very rare cause of inguinal hernia, especially in a postmenopausal woman.
A new-type linear accelerator (Linac) integrated with helical CT scanner was introduced into clinical application in 2019. In contrast with the design of CT-on-rails system, a diagnostic-quality 16slice CT scanner is compactly fixed behind the gantry of a C-arm Linac, and patient is sent through the scanner by moving the couch. The CT/Linac combination provides seamless workflow from simulation to treatment on one unit, and enables personalized adaptive radiotherapy. Recently, the CT-Linac was installed and put into clinical operation in our department. The aim of the present contribution was to report its technical characteristics and commissioning results as well as preliminary experience in clinical usage. Materials/Methods: The commissioning results of mechanical tests and imaging systems (MV CBCT and kV FBCT) tests were presented. IGRT accuracy was investigated through CBCT/FBCT image registration and couch correction. The machine performance over a period of three months, including stability of output, flatness and symmetry, were monitored and summarized. A series of end-to-end IMRT/ARC plans on different treatment sites were tested preclinically to estimate the overall accuracy for a treatment scheme. During the first stage of clinical usage, the results of pretreatment patient quality assurance (QA) for about 30 sIMRT plans on breast and rectum were reported. CBCT/FBCT image guidance were carried out in a treatment routine. Results of image registration and efficiency of the whole workflow were also evaluated. Results: The mechanical isocenter diameter was measured as less than 0.6 mm. The overall accuracy of CT-based IGRT was less than 0.5 mm considering couch precision from RT to CT position. Over the past three months, deviation of Linac output were 0.5AE0.3% from reference, and changes of flatness and symmetry were found less than 0.2%. Absolute point dose agreements for end-to-end tests and pretreatment QA plans between ion chamber measurements and TPS calculations were within 2% for all cases. The gamma passing rates of 3D dose distributions measured by Delta4 were better than 99% per plan and 95% per beam (3% DD, 2 mm DTA and 10% threshold), respectively. Concerning the IGRT workflow, it took about 2 min and 1.5 min from scanning to registration for CBCT and FBCT, respectively, both of which can provide accurate guidance for patient setup. Conclusion: The commissioning and pretreatment QA results show that the CT-Linac platform has a comparable machine performance as the Linac from other vendors. Other techniques like dIMRT and ARC deliveries will be clinically used in the next step. As the first clinical model type, its long-term reproducibility and stability are still under inspection. The integrated CT system, as a highlight, allows a diagnostic-quality visualization of internal patient anatomical structures for more accurate image guidance, and paves the way towards advanced and adaptive radiotherapy.
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