The incidence of carcinoma during pregnancy is reported to be 1:1000-1:1500 pregnancies with the breast carcinoma being the most commonly diagnosed. Since the fetus is most sensitive to ionizing ...radiation during the first two trimesters, there are mixed clinical opinions and no uniform guidelines on the use of radiotherapy during pregnancy. Within this study the pregnant female phantom in the second trimester, that can be used for radiotherapy treatment planning (as DICOM data), Monte Carlo simulations (as voxelized geometry) and experimental dosimetry utilizing 3D printing of the molds (as .STL files), was developed.
The developed phantom is based on MRI images of a female patient in her 18th week of pregnancy and CT images after childbirth. Phantom was developed in such a manner that a pregnant female was scanned "
" using MRI during pregnancy and CT after childbirth. For the treatment of left breast carcinoma, 3D conformal radiotherapy was used. The voxelized geometry of the phantom was used for Monte Carlo (MC) simulations using Monte Carlo N-Particle transport code
6.2 (MCNP).
The modeled photon breast radiotherapy plan, applied to the phantom, indicated that the fetus dose is 59 mGy for 50 Gy prescribed to the breast. The results clearly indicate that only 9.5% of the fetal dose is caused by photons that are generated in the accelerator head through scattering and leakage, but the dominant component is scattered radiation from the patient's body.
Background High energy electron linear accelerators (LINACs) producing photon beams with energies higher than 10 MeV are widely used in radiation therapy. In these beams, fast neutrons are generated, ...which results in undesired contamination of the therapeutic beam. In this study, measurements and Monte Carlo (MC) simulations were used to obtain neutron spectra and dose equivalents in vicinity of linear accelerator. Materials and methods LINAC Siemens Oncor Expression in Osijek University Hospital is placed in vault that was previously used for 60Co machine. Then, the shielding of the vault was enhanced using lead and steel plates. Measurements of neutron dose equivalent around LINAC and the vault were done using CR-39 solid state nuclear track detectors. To compensate energy dependence of detectors, neutron energy spectra was calculated in measuring positions using MC simulations. Results The vault is a source of photoneutrons, but a vast majority of neutrons originates from accelerator head. Neutron spectra obtained from MC simulations show significant changes between the measuring positions. Annual neutron dose equivalent per year was estimated to be less than 324 μSv in the measuring points outside of the vault. Conclusions Since detectors used in this paper are very dependent on neutron energy, it is extremely important to know the neutron spectra in measuring points. Though, patient dosimetry should include neutrons, estimated annual neutron doses outside the vault were far below exposure limit of ionizing radiation for workers.
Opioid use disorder (OUD) is an increasing public health problem. Transplant centers worldwide are being confronted with increasing numbers of patients with opioid use disorder and end stage organ ...disease. Opioid agonist therapy (OAT; ie, methadone, buprenorphine, and buprenorphine/naloxone) is a scientifically proven, effective, physician‐prescribed treatment for OUD. Although data in transplant populations remain limited, studies suggest that OAT does not appear to negatively affect graft or patient survival. Policies that require discontinuation of OAT for purposes of listing or transplantation contradict the evidence base for efficacy of OAT. Additional prospective outcomes studies on OAT and transplantation are needed. In the meantime, centers should not be asking patients to come off these effective treatments.
In this viewpoint on the opioid crisis and advances in opioid use disorder treatment, the authors argue that opioid agonist therapy should not be discontinued for purposes of transplant listing or transplantation.
Background
Monte Carlo (MC) simulations or measurements in anthropomorphic phantoms are recommended for estimating fetal dose in pregnant patients in radiotherapy. Among the many existing phantoms, ...there is no commercially available physical phantom representing the entire pregnant woman.
Purpose
In this study, the development of a low‐cost, physical pregnant female phantom was demonstrated using commercially available materials. This phantom is based on the previously published computational phantom.
Methods
Three tissue substitution materials (soft tissue, lung and bone tissue substitution) were developed. To verify Tena's substitution tissue materials, their radiation properties were assessed and compared to ICRP and ICRU materials using MC simulations in MV radiotherapy beams. Validation of the physical phantom was performed by comparing fetal doses obtained by measurements in the phantom with fetal doses obtained by MC simulations in computational phantom, during an MV photon breast radiotherapy treatment.
Results
Materials used for building Tena phantom are matched to ICRU materials using physical density, radiation absorption properties and effective atomic number. MC simulations showed that percentage depth doses of Tena and ICRU material comply within 5% for soft and lung tissue, up to 25 cm depth. In the bone tissue, the discrepancy is higher, but again within 5% up to the depth of 5 cm. When the phantom was used for fetal dose measurements in MV photon breast radiotherapy, measured fetal doses complied with fetal doses calculated using MC simulation within 15%.
Conclusions
Physical anthropomorphic phantom of pregnant patient can be manufactured using commercial materials and with low expenses. The files needed for 3D printing are now freely available. This enables further studies and comparison of numerical and physical experiments in diagnostic radiology or radiotherapy.
Mild vitamin C deficiency is a psychiatrically relevant nutritional state, with symptoms including apathy, fatigue, and low mood. Although complete vitamin C deficiency has largely been eradicated, ...mild deficiency remains common in certain populations. Here, we aimed to identify the prevalence of mild vitamin C deficiency in the inpatient psychiatric setting.
We identified 221 patients with plasma vitamin C levels collected on an inpatient psychiatric unit serving a metropolitan area between January 1, 2015, and March 7, 2022. We identified demographic (age, sex, race, housing status, Area Deprivation Index an index of neighborhood disadvantage), substance use (tobacco use, alcohol use), diagnostic (depressive, bipolar, psychotic, anxiety, substance use, catatonia, neurocognitive, autism spectrum), and micronutrient (folate, vitamin B
, vitamin D) risk factors.
was used as the diagnostic system. Bayesian log-normal regressions were constructed to predict vitamin C as a function of these risk factors. We used these same models to predict vitamin C as a function of significant risk factors.
We found that 64% (141 of 221; 95% confidence interval 57%-70%) of patients met criteria for mild vitamin C deficiency. While we did not identify robust demographic, substance use, or diagnostic-based risk factors, we found that folate and vitamin D strongly predicted vitamin C levels. To test the utility of these predictors, we simulated vitamin C as a function of folate and vitamin D and found that predicted deficiency remained high (
50%-55%), even when folate/vitamin D were sufficiently replete.
We find that vitamin C deficiency is highly prevalent in the inpatient psychiatric setting and remains high even when the relevant risk factor profile is favorable.
Atrial fibrillation (AF) is an arrhythmia characterized by disorganized electrical activity of the atria, secondary to ectopic focal discharge, leading to ineffective contraction and rapid heart ...rate. AF is the most common cardiac arrhythmia and is seen in approximately 1% to 2% of the population. Risk factors connected with AF include age, male gender, hypertension, valve disease, obesity, heart failure, diabetes, sleep apnea, cardiac surgery, smoking, alcohol consumption, and psychosocial stress. AF is associated with increased morbidity and mortality primarily due to coronary heart disease, heart failure, and stroke and has been associated with cognitive impairment and psychological distress. Treatment of AF should be focused on mitigating stroke risk as well as rate or rhythm control. AF is linked with depression, anxiety, and mood disorders as well as poor quality of life, but evidence suggests that these features can be improved with appropriate management. Further investigation is needed to inform and guide clinicians in therapeutic options and nonpharmacologic interventions for both the physical and psychiatric ramifications of AF.
Psychiatr Ann
. 2016;46(12):702–711.
At present, high energy electron linear accelerators (LINACs) producing photons with energies higher than 10 MeV have a wide use in radiotherapy (RT). However, in these beams fast neutrons could be ...generated, which results in undesired contamination of the therapeutic beams. These neutrons affect the shielding requirements in RT rooms and also increase the out-of-field radiation dose to patients. The neutron flux becomes even more important when high numbers of monitor units are used, as in the intensity modulated radiotherapy. Herein, to evaluate the exposure of patients and medical personnel, it is important to determine the full radiation field correctly. A model of the dual photon beam medical LINAC, Siemens ONCOR, used at the University Hospital Centre of Osijek was built using the MCNP611 code. We tuned the model according to measured photon percentage depth dose curves and profiles. Only 18 MV photon beams were modeled. The dependence of neutron dose equivalent and energy spectrum on field size and off-axis distance in the patient plane was analyzed. The neutron source strength (Q) defined as a number of neutrons coming from the head of the treatment unit per x-ray dose (Gy) delivered at the isocenter was calculated and found to be 1.12 × 1012 neutrons per photon Gy at isocenter. The simulation showed that the neutron flux increases with increasing field size but field size has almost no effect on the shape of neutron dose profiles. The calculated neutron dose equivalent of different field sizes was between 1 and 3 mSv per photon Gy at isocenter. The mean energy changed from 0.21 MeV to 0.63 MeV with collimator opening from 0 × 0 cm2 to 40 × 40 cm2. At the 50 cm off-axis the change was less pronounced. According to the results, it is reasonable to conclude that the neutron dose equivalent to the patient is proportional to the photon beam-on time as suggested before. Since the beam-on time is much higher when advanced radiotherapy techniques are used to fulfill high conformity demands, this makes the neutron flux determination even more important. We also showed that the neutron energy in the patient plane significantly changes with field size. This can introduce significant uncertainty in dosimetry of neutrons due to strong dependence of the neutron detector response on the neutron energy in the interval 0.1–5 MeV.
•A model of medical linear accelerator (Siemens ONCOR) was built using the MCNP611 code.•Neutron dose equivalent and energy spectrum in the patient plane was analyzed.•Neutron flux increases with field size.•Field size has almost no effect on the shape of neutron dose profiles.•The mean energy of the neutrons increases with collimator opening at isocenter.
Alcohol‐related liver disease (ALD) is the leading indication for liver transplantation worldwide. Since Mathurin et al. described their experience in providing early liver transplantation for ...patients with ALD in 2011, other centers have followed suit with generally favorable survival outcomes. This patient population poses a unique clinical challenge given the expedited nature of the evaluation and the lack of any significant sobriety period prior to transplantation. The SALT (Sustained Alcohol Use Post‐Liver Transplant) score is a standardized psychometric tool increasingly used to help stratify the risk of relapse and guide listing decisions for these challenging clinical situations. In 2018, our center introduced a protocol for early liver transplantation for acute alcohol‐related hepatitis (AAH). In this article, we offer a retrospective review of 26 patients transplanted between May 2018 and May 2021, including at least 1‐year follow‐up, and compare outcomes to initial SALT scores; we further identify additional factors that may impact post‐transplant success. As transplant committees continue to weigh the ethical dilemma of denying lifesaving treatment against the obligation to remain stewards of a limited resource, we aim to contribute to a more nuanced understanding of risk regarding early transplantation for ALD.
Radioterapija megavoltnim snopovima fotona linearnog akceleratora oblik je lokalnog onkološkog liječenja.
Njezin je cilj predati propisanu apsorbiranu dozu ciljnom volumenu, uz što nižu dozu okolnomu ...zdravom tkivu. Proces se sastoji od niza koraka u kojima sudjeluje tim stručnjaka iz različitih područja. Veliki broj postupaka i ljudi uključenih u radioterapijski proces, nepouzdanosti uređaja te pomaci bolesnika i unutrašnjih
organa tijekom terapije mogu uzrokovati odstupanja između planirane i stvarne raspodjele doze. U ovom radu procijenili smo utjecaj pogreške položaja bolesnika tijekom terapije na raspodjelu doze, te na veličine koje služe za procjenu kvalitete plana.
Pogreške u položaju bolesnika ispitane su u skupini od 35 bolesnika. Te smo pogreške simulirali na pet bolesnika, koristeći se 3D programom za planiranje XiO (CMS Inc., St. Louis, MO, Elekta). Ispitali smo razlike u raspodjeli doze između planiranog i stvarnog položaja. Dodatno, utjecaj pogrešaka na odabir plana zračenja provjerili smo analizirajući promjene u dozno-volumnom histogramu (DVH), pokrivenost planiranog volumena (engl. PTV conformity index, CIPTV) i jednoličnost raspodjele doze u ciljnom volumenu
(engl. homogeneity index, HI).
Simulacije pokazuju da promjene u položaju bolesnika mogu uzrokovati značajne razlike između planirane i stvarne raspodjele doze. Kod nekih bolesnika ako se ne korigiraju pogreške, CIPTV postaje manji od 97 %
što znači da plan više nije prihvatljiv za zračenje. Iznenađuje da HI nije ovisan o pomacima bolesnika kao CIPTV.
Rezultati pokazuju potrebu za smanjenjem pogrešaka, što se može postići provođenjem kontrole kvalitete u radioterapiji.
An external beam radiotherapy (EBRT) using megavoltage beam of linear accelerator is usually the treatment of choice in cancer patients. The goal of EBRT is to deliver the prescribed dose to the ...target volume, with as low as possible dose to the surrounding healthy tissue. A large number of procedures and different professions involved in radiotherapy, uncertainty of equipment and daily patient set-up errors can cause a difference between the planned and delivered dose.We investigated a part of this difference caused by measuring daily patient set-up errors for 35 patients. These set-up errors were simulated on five patients, using 3D treatment planning software XiO. The simulation investigated differences in dose distributions between the planned and shifted geometry. Additionally, we investigated the influence of the error on treatment plan selection by analysing changes in dose volume histograms, planning target volume conformity index (CIPTV), and homogeneity index (HI).Simulations showed that patient daily set-up errors can cause significant differences between the planned and actual dose distributions. Moreover, for some patients, those errors could affect the choice of treatment plan since CIPTV fell under 97%. Surprisingly, HI was not as sensitive to set-up errors as CIPTV. Our results have confirmed the need to minimise daily set-up errors through quality assurance programmes.
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