MRI artifact simulation for clinically relevant MRI sequences for guidance of prostate HDR brachytherapy

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10-8 to (3.6 ± 0.14) × 10-8 nC Gy-1 mCi-1 mm-2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively. The prototype detectors provide an unprecedented sensitivity thanks to its monolithic amplification stage. Future investigation of this technology will include the optimisation of the packaging technique.

Magnetic Resonance Imaging Artifact Elimination in the Diagnosis of Female Pelvic Abscess under Phase Correction Algorithm

In order to explore the effect of magnetic resonance imaging (MRI) based on phase correction algorithm in diagnosing female pelvic abscess, firstly, the effect of phase correction algorithm on eliminating MRI image motion artifacts was studied, then it was applied to 71 female pelvic cases admitted to our hospital in the diagnosis of abscess patients with magnetic resonance imaging technology, and the results were compared with the results of multislice spiral CT and laparoscopy to explore the accuracy of MRI and CT. It was found that the results of MRI examination were close to those of laparoscopy, and the difference was not statistically significant (P > 0.05); the results of CT examination and laparoscopy were significantly different, and the difference was statistically significant (P < 0.05); in addition, the results of CT examination, the number of bacterial cysts (43 cases) and tuberculous cysts (12 cases), were significantly lower than the results of MRI (50 cases, 18 cases), and the difference was statistically significant (P < 0.05). The size of the mass shown by the MRI examination (4.1  cm × 4.2  cm × 3.9 cm～13.9  cm × 9.5  cm × 8.7 cm) was larger than the size of the mass revealed by the CT examination (5.2  cm × 4.3  cm × 4.1 cm～15.5  cm × 10.1  cm × 9.6 cm), the difference between the two was statistically significant (P < 0.05), and it was closer to the results of laparoscopic pathology (4.1  cm × 4.3  cm × 3.9 cm～14.1  cm × 9.3  cmP < 0.058.7 cm). In short, the phase correction algorithm could eliminate the motion artifacts of MRI images. In the imaging diagnosis of female pelvic abscess, the MRI diagnosis based on the phase correction algorithm is more ideal than the diagnosis of multislice spiral CT. It can be used as a reference basis for clinical disease treatment.