The British journal of radiology
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We have studied and analysed the magnitude of interfraction set-up errors and gold seed marker and prostate displacement in 118 patients using three gold seeds implanted within the prostate. Set-up errors and gold seed marker displacements were determined from bony anatomy and gold seed marker mismatch between the electronic portal image and the simulation digitally reconstructed radiograph (DRR), respectively. Prostate displacement relative to bony anatomy was determined from the difference between gold seed marker and bony anatomy displacement. ⋯ The isocentre set-up random errors were 1.6 mm (1.2-4.8 mm) for AP, 1.3 mm (0.6-2.5 mm) for L-R and 1.3 mm (1.0-2.6 mm) for SI directions. The mean and standard deviation of the prostate displacement systematic error relative to bony anatomy was 0.0+/-1.4 mm for AP, 0.0+/-1.1 mm for L-R and -0.2+/-2.4 mm for SI directions. Prostate displacement random errors were 1.5 mm (1.2-3.3 mm) for AP, 0.9 mm (0.4-1.5 mm) for L-R and 1.4 mm (1.2-2.4 mm) for SI directions.
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The aim of the study was to determine whether the sternal notch changes in its z-axis position in the arms raised vs arms down position on CT scans. A retrospective study was made of 132 consecutive CT scans of the neck and chest. We recorded the table position of the sternal notch and the most inferior slice through the thyroid gland on both scans, and the table position on the chest CT where the configuration of the head and neck vessels most closely corresponded to their configuration on the sternal notch slice of the neck CT. ⋯ Mean upward motion of the sternal notch relative to the thyroid was 8.98 mm (p<0.0001). In conclusion, the sternal notch moves upwards relative to the CT table and soft tissues in the neck and upper mediastinum when the arms are raised; the degree of upward motion is greater in males. This may have implications when categorizing nodes at the cervicothoracic junction on staging CT examinations, when deciding if nodes might be accessible to ultrasound-guided biopsy, and in classifying goitres.
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Poly(ADP-ribose) polymerase-1 (PARP-1) facilitates DNA single-strand break-base excision repair to maintain genomic stability. Inhibition or loss of PARP activity leads to a recombinogenic phenotype characterized by increased sister chromatid exchange. Deficiency in homologous recombination (HR) owing to loss of BRCA1 or BRCA2 is associated with hereditary cancers of the breast, ovary, pancreas and prostate. ⋯ We believe the underlying cytotoxic mechanism is due to PARP inhibitor-mediated suppression of repair of DNA single-strand breaks, which are converted to DNA double-strand breaks at replication. These replication-associated double-strand breaks, which are normally repaired by HR, become cytotoxic in cells defective in HR. Using a DNA repair inhibitor alone to selectively kill a tumour represents an exciting new concept in cancer therapy.
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The aim of this study was to determine whether the use of whole-body (18)F-fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET)/CT alters staging and management of nasopharyngeal carcinoma (NPC) when compared with current staging practice. 52 patients with Stage III-IV NPC without distant metastases on chest X-ray/CT, abdominal ultrasound or bone scan were recruited for the study. Whole-body (18)F-FDG PET/CT and MRI of the head and neck were performed. The scans were compared for extent of the primary tumour (PT), cervical nodal metastases (CNM) and distant metastases (DM). ⋯ There was also variation among the extent of CNM in four nodes of the retropharyngeal region, with the nodes being positive on MRI. (18)F-FDG PET /CT did not identify any additional distant metastases but did identify a second primary tumour in the colon. The additional use of (18)F-FDG PET/CT did not "up-stage" the overall stage or change management in any patient. In conclusion, there is discordance between MRI and (18)F-FDG PET/CT, and the additional use of (18)F-FDG PET/CT for the current assessment of NPC at diagnosis does not appear to be justified in this cohort of patients.