Development and validation of the low-cost pregnant female physical phantom for fetal dosimetry in MV photon radiotherapy.

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.

TRACHEOBRONCHIAL MORPHOMETRY CORRELATES WITH DEMOGRAPHIC CHARACTERISTICS AND INFECTIONS IN CRITICALLY ILL PATIENTS.

Tracheal measurements in the intensive care unit (ICU) are important for the choice of endotracheal tube and may correlate with patient demographic characteristics and infections. The study included 42 surgical patients, age 60 [48-71] years, who underwent diagnostic chest computed tomography (CT) scans during treatment in the ICU, Osijek University Hospital, in 2019 and 2020. CT scans were analyzed using AW Server 3.2. Measurement analysis showed that the diameters of the tracheobronchial tree, the length of the trachea and left main bronchus were significantly larger in men compared to women (p<0.05 all). The smallest tracheal upper diameter was 15.25 [IQR 11.8-18.8] mm vs. 17.95 [13.55-20.05] mm in septic and nonseptic patients, respectively (p=0.028). A total of 26 patients who underwent CT scans developed nosocomial pneumonia. It was right-sided in 15, left-sided in 6 and bilateral in 5 patients, and correlated significantly with the left main bronchus length (ρ=0.515, p=0.007). No correlation was observed between tracheobronchial measurements and length of ICU treatment, number of hours spent on mechanical ventilation, or survival. A larger study could provide better data on the importance of tracheobronchial tree measurements in ICU patients.

THE ROLE OF INTERVENTIONAL RADIOLOGISTS IN THE TREATMENT OF COMPLICATIONS IN UROLOGIC PATIENTS.

Higher turnaround of urologic patients in the tertiary clinical center can lead to more accompanying complications, ranging from 1% to 55% for various procedures, with the incidence of vascular injuries varying from 0.43% up to 9.5%. In patients with impaired renal function, it is imperative to prevent the loss of normal kidney function and potential hemodialysis. Being minimally invasive, endovascular procedures such as renal artery embolization (RAE) can treat major and life-threatening complications, but good and prompt communication between urologists and interventional radiologist is necessary for fast and effective treatment. Absolute contraindications for RAE are the presence of acute infection and previously known anaphylactic reaction to the iodine contrast media, while previous mild or moderate allergic reactions to iodine contrast media are not contraindications for RAE. Currently used embolic agents can be divided into temporary and permanent embolization agents. While the temporary embolization agent available is a gelatin sponge that could be used as complementary material or stand-alone, for permanent embolization interventional radiologists use microparticles, microspheres, liquid embolic agents, coils, and microcoils. RAE procedures are considered to be safe with a low incidence of complications, with non-target embolization being the most serious one. Postembolization syndrome is considered to be the most common adverse effect and it involves around 90% of patients. The overall results show that RAE is a safe, minimally invasive procedure that can effectively treat significant complications caused by other urologic procedures, with the reported success rates of 87%-100%.

A rare presentation of leiomyosarcoma metastasis to the cervical spine: A case report and a brief review.

Background: Leiomyosarcoma (LMS) is a rare malignancy that originates from smooth muscle. The most common sites of metastases include the lungs, liver, kidney, and skin. Notably, metastases of LMS to the central nervous system/or spine are extremely rare. When a cervical spinal LMS lesion was encountered, the patient successfully underwent gross total tumor resection with negative margins. Case Description: A 63-year-old female had undergone an anterior cervical C5-C7 diskectomy and fusion 18 years ago and resection of a retroperitoneal LMS 3 years ago. She newly presented with right-sided numbness and pain of 2 months duration that correlated with a focal right-sided C5-level hemiparesis (i.e., 4/5 motor strength). When the cervical magnetic resonance demonstrated a right-sided C5 intralaminar mass with extension into the C5-C6 foramen, she underwent posterior tumor resection; pathologically, this proved to be an LMS metastasis. Respectively, 1- and six months postoperatively, follow-up magnetic resonance imaging scans showed no tumor recurrence; she tolerated adjuvant oncological treatment accompanied by physical therapy. However, in one postoperative year, the lesion recurred, and she is presently under consideration for additional surgical management. Conclusion: Gross total surgical resection is the first line of treatment for patients with metastatic LMS. Here, a patient with a C5 laminar/C5-C6 foraminal bony LMS metastasis underwent posterior tumor resection accompanied by adjuvant oncological treatment but exhibited disease recurrence within one postoperative year.

Ventilation Management in a Patient with Ventilation-Perfusion Mismatch in the Early Phase of Lung Injury and during the Recovery.

Chest trauma is one of the most serious and difficult injuries, with various complications that can lead to ventilation-perfusion (V/Q) mismatch and systemic hypoxia. We are presenting a case of a 53-year-old male with no chronic therapy who was admitted to the Intensive Care Unit due to severe respiratory failure after chest trauma. He developed a right-sided pneumothorax, and then a thoracic drain was placed. On admission, the patient was hemodynamically unstable and tachypneic. He was intubated and mechanically ventilated, febrile (38.9 °C) and unconscious. A lung CT showed massive non-ventilated areas, predominantly in the right lung, guiding repeated therapeutic and diagnostic bronchoalveolar lavages. He was ventilated with PEEP of 10 cmH2O with a FiO2 of 0.6-0.8. Empirical broad-spectrum antimicrobial therapy was immediately initiated. Both high FiO2 and moderate PEEP were maintained and adjusted according to the current blood gas values and oxygen saturation. He was weaned from mechanical ventilation, and non-invasive oxygenation was continued. After Stenotrophomonas maltophilia was identified and treated with sulfamethoxazole/trimethoprim, a regression of lung infiltrates was observed. In conclusion, both ventilatory and antibiotic therapy were needed to improve the oxygenation and outcome of the patient with S. maltophilia pneumonia and V/Q mismatch.