Medicina nuclear y radioterapia

This retrospective study explored 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) as an aid in target delineation among a first-group of five patients with single or multiple moving lung tumors planned for Vero stereotactic body radiation therapy (SBRT). Computed tomography (CT)-based free-breathing, end-inspiration, and end-expiration lung target volumes generated a single internal target volume (ITV). ITVs were compared to a thresholded 40% maximum standard uptake value FDG-PET target volume (CTVpet), a contour assumed to be a surrogate for lung target motion during quiet breathing. Planning target volumes (PTV) and relevant lung planning constraints determined clinical execution of Vero SBRT. A mean 28% PTV expansion by adding in a CTVpet contour to the CT-based ITV converted two (40%) of five cases from SBRT fractionation (40 Gy in four every other day fractions) to conventional fractionation (30 Gy in ten daily fractions). In all five cases, CTVpet contours captured target motion not enclosed by the CT-based ITV. Vero SBRT radiation plans achieved effective normal tissue sparing without compromise of PTV target coverage. A single instance of less than 30-day posttherapy grade 2 fatigue occurred; no pulmonary toxicity has been observed in the 3-month follow-up period. Thresholded CTVpet contours impacted target delineation and clinical delivery of Vero SBRT treatment.

Objective: To study whether subvolumes with a high pre-chemoradiotherapy (CRT) FDG uptake could identify residual metabolically-active volumes (MAVs) post-CRT within individual esophageal tumors. Accurate identification will allow simultaneous integrated boost to these subvolumes at higher risk to improve clinical outcomes.
Methods: Twenty patients with esophageal cancer were treated with CRT plus surgery and underwent FDG PET/CT scans before and after CRT. The two scans were rigidly registered. Seven MAVs pre-CRT and four MAVs post-CRT within a tumor were defined with various SUV thresholds. The similarity and proximity between the MAVs pre-CRT and post-CRT were quantified with three metrics: fraction of post-CRT MAV included in pre-CRT MAV, volume overlap and centroid distance.
Results: Eight patients had no residual MAV. Six patients had local residual MAV (SUV ≥2.5 post-CRT) within or adjoining the original MAV (SUV ≥2.5 pre-CRT). On average, less than 65% of any post-CRT MAVs was included in any pre-CRT MAVs, with a low volume overlap <45%, and large centroid distance >8.6 mm. In general, subvolumes with higher FDG-uptake pre-CRT or post-CRT had lower volume overlap and larger centroid distance. Six patients had new distant MAVs that were determined to be inflammation from radiation therapy.
Conclusions: Pre-CRT PET/CT cannot reliably identify the residual MAVs within individual esophageal tumors. Simultaneous integrated boost to subvolumes with high FDG uptake pre-CRT may not be feasible.

Advances in the treatment of melanoma with novel systemic therapies have meaningfully increased survival of patients. The brain is a common early site for melanoma metastases. WBRT is of limited effectiveness for radioresistant histologies such as melanoma and has been associated with white matter change and cognitive dysfunction. Prior studies of leukoencephalopathy after treatment with whole-brain radiation therapy (WBRT) and/or stereotactic radiosurgery (SRS) have focused on pathologies where chemotherapy is reflexively used in the majority of patients. The study’s aim was to evaluate the risk of leukoencephalopathy in patients with melanoma brain metastases receiving stereotactic radiosurgery and whole-brain radiation therapy versus SRS alone. We retrospectively reviewed 63 patients who underwent SRS with or without WBT between April 1988 and December 2012. Degree of leukoencephalopathy was evaluated on T2 and FLAIR MRI sequences using a simple, previouslydescribed method. A significantly lower proportion of patients treated with SRS developed leukoencephalopathy in long-term follow up compared to patients treated with SRS and WBRT. This study demonstrates an increased risk of leukoencephalopathy following WBRT compared to SRS alone in a cohort of melanoma brain metastases patients with a low rate of treatment with alkylating chemotherapeutic agents.

Radiation-induced leiomyosarcoma is a very rare complication following irradiation of primary malignancies. In the chest wall, it is usually secondary to radiotherapy for breast cancer or lymphoma. Esophageal malignancy is a radiation dose-related complication of radiotherapy for breast cancer, but its absolute risk is low. A 61-year-old woman presented with an esophageal leiomyosarcoma 13 years after surgery plus mediastinal irradiation (55 Gy) for a stage III thymoma. Esophageal sarcoma is an uncommon tumor, reported sporadically in the literature. Radiotherapy is frequently used in the treatment of carcinoma of the esophagus, and the increased risk of development of sarcoma arising in irradiated fields is well known. The increasing use of radiotherapy for thymoma suggests that radiation-associated malignancies of the esophagus may be seen more frequently in the future. To the best of our knowledge, this is the first report of radiation-induced esophageal leiomyosarcoma after mediastinal irradiation of a thymoma.

Introduction: Cerebral palsy (CP) is caused by abnormalities in the developing brain leading to an impairment of muscle coordination and movement control in the body. Neonatal hypoxic-ischemic brain injury and hypoxic ischemic encephalopathy (HIE) are major causes of CP. Neurodegenerative disorders can be treated with human embryonic stem cells (hESC). Magnetic resonance imaging (MRI), positron emission tomography and single photon emission computed tomography (SPECT) scan are some of the imaging modalities for CP, but among all SPECT scan is more sensitive in detecting abnormalities in the brain. SPECT scan is an effective tool for the detection of cerebral blood flow, cerebral impairment and local brain metabolism. The present study was conducted to evaluate the diagnostic modality of SPECT scan that can assess the patient with CP before and after hESC therapy.
Methodology: The study included the patients with CP for whom SPECT scan was performed before and after the therapy. Technetium-hexa methyl propylene aminoxime (Tc-HMPAO) SPECT scan was analyzed to assess the number of hypoperfused lesions/ areas in the brain and the percentage of improvement by hESC treatment. The patients were scored clinically using GMFCS scores.
Results: Overall, 88 patients aged 2 months to 18 years with clinical manifestations of CP had SPECT scan performed before and after the therapy. The total treatment days varied from 31 to 310 days. All the subjects showed improvement in SPECT scan. Majority of subjects (n=58) had significant SPECT scan (>60%) change, followed by moderate SPECT scan (>30% <60%) change in 15 subjects, mild scan (>10% <30%) change in 3 subjects. These patients also showed a clinical improvement as reflected in their GMFCS scores.
Conclusion: SPECT scan can be a crucial diagnostic modality to assess patients with CP.

The principles of linear accelerator are: the accelerator emits two types of radiation that are photon and electron. However, when we were doing the research and working on it, we have found that neutrons have emitted from the accelerator.

This paper aims to show some results of measuring neutrons from a linear accelerator at Dong Nai General Hospital. The results of this experiment will be used to ensure the safety of radiation as well as the background for the incoming research.

If advances on radiotherapy allowed closing the page on poor Hodgkin Lymphoma prognosis, a new one opens dramatically on the long term effects, as second malignancies radiotherapy-related. Clinician and surgeons are faced to a new dilemma towards these patients, when surgical incision and intervention has to be performed in the radiation field, known to be fraught with serious consequences from delayed cicatrisation to death.

High dose radiotherapy is a treatment for nasopharyngeal carcinoma (NPC), but can result in radiation-induced changes to the cervical spine, which may be difficult to recognize. Pathological fractures occurring after radiation therapy for soft tissue tumors are rare. In this context, we report a rare case of delayed Osteoradionecrosis of a cervical vertebral body (C5) causing myeloradiculopathy. The patient, a 54-year-old man, received radical radiotherapy for NPC 10 years previously. Anterior decompression and stabilization with internal fixation was performed. Pathology reported necrotic tissue and no evidence of malignancy. Postoperatively, the patient’s neck pain improved, and he recovery muscle power in all four extremities. Early diagnosis is essential for this curable condition. Emergency surgical intervention for decompression and stabilization with internal fixation may result in complete neurological recovery.

Fever of unknown origin (FUO) is a challenging condition in the practice of internal medicine. It frequently requires use of complicated tests and applications in the diagnostic workup. We here report a patient presented with FUO who was diagnosed with osteomyelitis by biopsy after a positive Fludeoxyglicose Positron Emission tomography (FDG-PET) scan.