Use of motion tracking in stereotactic body radiotherapy: Evaluation of uncertainty in off-target dose distribution and optimization strategies

n/

Vaccination against SARS-CoV-2 in pregnancy during the Omicron wave: the prospective cohort study of the Italian obstetric surveillance system

Objectives: Evidence on the effects of the SARS-CoV-2 Omicron variant on vaccinated and unvaccinated pregnant women is sparse. This study aimed to compare maternal and perinatal outcomes of women infected with SARS-CoV-2 during the Omicron wave in Italy, according to their vaccine protection.Methods: This national prospective cohort study enrolled pregnant women with a positive SARS-CoV-2 nasopharyngeal swab within 7 days of hospital admission between 1 January and 31 May, 2022. Women who received at least one dose of vaccine during pregnancy and those who completed the vaccine cycle with the first booster were considered protected against moderate or severe COVID-19 (MSCD). A multivariable logistic regression model evaluated the association between vaccine protection and disease severity. Maternal age, educational level, citizenship, area of birth, previous comorbidities, and obesity were analysed as potential risk factors. Results: MSCD was rare (41/2147, 1.9%; 95% CI, 1.4-2.6), and the odds of developing it were significantly higher among unprotected women (OR, 2.78; 95% CI, 1.39-5.57). Compared with protected women (n = 1069), the unprotected (n = 1078) were more often younger, with lower educational degrees, and foreigners. A higher probability of MSCD was found among women with previous comorbidities (OR, 2.86; 95% CI, 1.34-6.12) and those born in Asian countries (OR, 3.05; 95% CI, 1.23-7.56). The percentage of preterm birth was higher among women with MSCD compared with milder cases (32.0% [8/25] versus 8.4% [161/1917], p < 0.001) as well as the percentage of caesarean section (52.0% [13/25] versus 31.6% [606/1919], p 0.029). Discussion: Although severe maternal and perinatal outcomes were rare, their prevalence was significantly higher among women without vaccine protection. Vaccination during pregnancy has the potential to protect both the mother and the baby, and it is therefore strongly recommended. Edoardo Corsi Decenti, Clin Microbiol Infect 2023;29:772 (c) 2023 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved

Hypofractionated simultaneous integrated boost (IMRT-SIB) with pelvic nodal irradiation and concurrent androgen deprivation therapy for high-risk prostate cancer: results of a prospective phase II trial

n/

Direct tumor in vivo dosimetry in highly-conformal radiotherapy: a feasibility study of implantable MOSFETs for hypofractionated extracranial treatments using the Cyberknife system.

PURPOSE: In highly-conformal radiotherapy, due to the complexity of both beam configurations and dose distributions, traditional in vivo dosimetry is unpractical or even impossible. The ideal dosimeter would be implanted inside the planning treatment volume so that it can directly measure the total delivered dose during each fraction with no additional uncertainty due to calculation models. The aim of this work is to verify if implantable metal oxide semiconductors field effect transistors (MOSFETs) can achieve a sufficient degree of dosimetric accuracy when used inside extracranial targets undergoing radiotherapy treatments using the Cyberknife system. METHODS: Based on the preliminary findings of this study, new prototypes for high dose fractionations were developed to reduce the time dependence for long treatment delivery times. These dosimeters were recently cleared and are marketed as DVS-HFT. Multiple measurements were performed using both Virtual Water and water phantoms to characterize implantable MOSFETs under the Cyberknife beams, and included the reference-dosimetry consistency, the dependence of the response on the collimator size, on the daily delivered dose, and the time irradiation modality. Finally a Cyberknife prostate treatment simulation using a body phantom was conducted, and both MOSFET and ionization readings were compared to Monte Carlo calculations. The feasibility analysis was conducted based on the ratios of the absorbed dose divided by the dose reading, named as "further calibration factor" (FCF). RESULTS: The average FCFs resulted to be 0.98 for the collimator dependence test, and about 1.00 for the reference-dosimetry test, the dose-dependence test, and the time-dependence test. The average FCF of the prostate treatment simulation test was 0.99. CONCLUSIONS: The obtained results are well within DVS specifications, that is, the factory calibration is still valid for such kind of treatments using the Cyberknife system, with no need of further calibration factors to be applied. The final accuracy of implantable MOSFETs when used for such kind of treatments was estimated to be within +/- 4%. Additional investigations using dose/fraction higher than 12 Gy, different beam configurations, and tracking systems could extend the present findings to other kind of treatments. MOSFET technology was proven to have high versatility in fast adaptation of existing detectors to new applications. It is plausible to expect a general feasibility of implantable MOSFET technology for in vivo dosimetry of the extracranial-targets treatments using the Cyberknife, provided each particular application will be validated by suitable both physical and clinical studies

In-vivo dosimetry for field sizes down to 6~\texttimes~6~mm2 in shaped beam radiosurgery with microMOSFET

International audienc