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PubMed2006

Monte Carlo dose calculations for a 6-MV photon beam in a thorax phantom.

PURPOSE: In this study we evaluated the accuracy of the Monte Carlo (MC) and effective path length (EPL) methods for dose calculations in the inhomogeneous thorax phantom. MATERIALS AND METHODS: The Philips SL 75/5 linear accelerator head was modeled using the MCNP4C Monte Carlo code. An anatomic inhomogeneous thorax phantom was irradiated with a 6-MV photon beam, and the doses along points of the central axis of the beam were measured by a small ionization chamber. The central axis relative dose was calculated by the MCNP4C code and the EPL method in a conventional treatment planning system. The results of calculations and measurements were compared. RESULTS: For all measured points on the thorax phantom the results of the MC method were in agreement with the actual measurement (local difference was less than 2%). For the EPL method, the amount of error was dependent on the field size and the point location in the phantom. The maximum error was +19.5 and +26.8 for field sizes of 10 x 10 and 5 x 5 cm2 for lateral irradiation. CONCLUSION: Our study showed large, unacceptable errors for EPL calculations in the lung for both field sizes. The accuracy of the MC method was better than the recommended value of 3%. Thus, application of this method is strongly recommended for lung dose calculations, especially for small field sizes.

Algorithms↗

PubMed1990

High energy (42-66 MeV reactions) fast neutron dose optimization studies in the head and neck, thorax, upper abdomen, pelvis and extremities.

Five hundred and fifty patients were entered into a set of dose-searching studies designed to determine normal tissue tolerance to high energy (42-66 MeV reactions) fast neutrons delivered in 12 equal fractions over 4 weeks. Participating institutions included: The Fermilab (66 MeV p+----Be), The University of Washington (50 MeVp+----Be), U.C.L.A. (45 MeVH-----Be), M.D. Anderson Hospital (42 MeVH-----Be), and The Cleveland Clinic (42 MeVp+----Be). Patients were stratified by treatment facility and then randomized to receive 16, 18 or 20 Gy for tumors located in the upper abdomen or pelvis, and 18, 20 or 22 Gy for tumors located in the head and neck, thorax or extremities. Following completion of the randomized protocols, additional patients were studied at the 20.4 Gy level in the head and neck, thorax and pelvis. Normal tissue effect scoring was accomplished using the RTOG-EORTC acute and late normal tissue effect scales. Acute Grade 3 + toxicity rates in the head and neck were 19% for 20/20.4 Gy and 20% for 22 Gy. Time adjusted late toxicity rates in the head and neck at 12 months were 15% for 20/20.4 Gy and 0% for 22 Gy. The 18 Gy treatment arm of the head and neck protocol was dropped early in the study after only two patients were accrued. For cases treated in the thorax, acute Grade 3 + toxicity rates were 6% for 18 Gy, 15% for 20/20.4 Gy and 7% for 22 Gy. Late toxicity rates at 12 months were 0% for 18 Gy, 11% for 20/20.4 Gy and 18% for 22 Gy. Acute Grade 3+ toxicity rates in the upper abdomen were 0% for 16 Gy, 8% for 18 Gy and 12% for 20 Gy. There were no Grade 3 + late toxicities in the upper abdomen. In the pelvis, acute Grade 3 + toxicity rates were 0% for 16 Gy, 3% for 18 Gy and 3% for 20/20.4 Gy. Late Grade 3 + toxicities at 24 months were 20% for 16 Gy, 5% for 18 Gy and 24% for 20/20.4 Gy. In extremities, acute Grade 3 + toxicity rates were 7% for 20 Gy and 21% for 22 Gy while at 12 months, late Grade 3 + toxicity rates were 14 and 35%, respectively. The 18 Gy treatment arm of the extremities protocol was dropped early in the study after only two patients were accrued. Factors associated with normal tissue effects in addition to treatment dose are discussed.

Abdominal Neoplasms↗

PubMed2007

The feasibility of three-dimensional displays of the thorax for preoperative planning in the surgical treatment of lung cancer.

OBJECTIVE: Three-dimensional (3D) displays of anatomic structures have become feasible for preoperative planning in some surgical procedures. There have been no reports, however, on the use of 3D displays for surgical treatment of lung cancer. We hypothesized that 3D displays of the thorax are useful for preoperative planning for lung cancer. METHODS: Based on virtual reality technologies, we rendered 3D displays of the thorax from two-dimensional (2D) computed tomographic (CT) images of six anonymous patients, some of whom underwent surgical removal of lung cancer. For determining the resectability of lung cancer, we tested 17 participants with varying degrees of surgical skills to view 3D displays and read 2D CT images of these thoracic cavities in a randomized order. We measured their performance in terms of the accuracy of predicted resectability, the confidence of their prediction, planning time used, and workload experienced. RESULTS: The results demonstrated that viewing 3D displays of thoracic cavities has significant advantages over reading 2D CT images in determining the resectability of lung cancer: increasing the accuracy of predicted resectability by about 20%, enhancing the confidence of the prediction by about 20%, decreasing planning time by about 30%, and reducing workload by about 50%. All participants preferred viewing 3D displays to reading 2D CT images for preoperative planning. Junior residents found 3D displays of thoraces more useful than senior residents. CONCLUSIONS: It is feasible to use 3D displays of the thorax for preoperative planning in treating lung cancer. Using 3D displays in surgical treatment of lung cancer has potential benefits, once the technique is perfected.

Clinical Competence↗

PubMed1988

Neurogenic tumors of the thorax.

Neurogenic tumors of the thorax are observed in all age groups, although they are rare in the elderly. They are more likely to be malignant in the child than in the adult. Tumors of the autonomic system are common in children, whereas the nerve sheath tumors are more likely to be found in adults. The malignant lesions are almost always symptomatic and the benign lesions asymptomatic, except in the child, in whom a benign lesion may result in symptoms because of its size relative to the volume of the child's thorax. Intraspinal canal extension, although relatively infrequent, should be sought for in all paravertebral tumors, for a significant percentage of these may be initially asymptomatic. Excision of such an hourglass tumor without foreknowledge of such extension may lead to serious spinal cord complications. Surgical excision of most of these tumors is sufficient except for the malignant lesions, especially in infancy and childhood, for which the addition of postoperative irradiation and chemotherapy may be beneficial. The prognosis after the removal of benign neurogenic tumors of the thorax is excellent. In the infant or child with Stage III or IV neuroblastoma, ganglioneuroblastoma, or an Askin tumor, the prognosis is poor. In the adult with a malignant neurogenic sarcoma or a malignant paraganglioma, the prognosis likewise is grave.

Autonomic Nervous System Diseases↗

PubMed1999

Magnetic resonance imaging of the thorax. Past, present, and future.

Magnetic resonance is a valuable modality of extreme flexibility for specific problem-solving capability in the thorax. This article reviews MR applications in the imaging of great vessels, which are currently the most important applications in the thorax; other established applications in the thorax; and pulmonary functional MR imaging.

Aortic Diseases↗

PubMed1999

Patients' evaluation of pain and nurses' management of analgesics after surgery. The effect of a study day on the subject of pain for nurses working at the thorax surgery department.

The effect of a study day on the subject of pain for nurses working at the thorax surgery department The aims of this investigation were: to describe patients' evaluation of pain and the treatment of pain after thorax surgery via sternotomy; to repeat the evaluation with another group of patients following a study day for nurses, featuring pain and pain treatment; and to examine whether the study day influenced the nurses in their treatment of pain. The investigation included daily evaluation of pain using a visual analogue scale (VAS), and an interview with the patients before discharge, where they were asked to review their experience of pain and its treatment. The nurses on the thorax surgery ward and on the intensive care unit (ICU) completed a questionnaire before and after the study day. Finally, a retrospective study of the case notes of the patients taking part was carried out. The results of the investigation showed a low assessment of pain by most patients during the daily evaluation. Asked to recall their pain when interviewed, the rating was higher. A small group of patients had more evident pain than others. When administering opiates the ICU nurses often chose a lower dose than the standing order prescribed. After the study day the nurses gave larger doses of intravenous opioids and the patients experienced less pain.

Analgesics, Opioid↗

PubMed1998

Dose reduction in thorax radiography in simulated neonates with additional filtration and digital luminescence radiography.

PURPOSE: To determine the minimum acceptable radiation dose for an adequate image quality in thorax a.p. radiographs of neonates using mobile X-ray equipment. MATERIAL AND METHODS: The influence of additional filtration (1.0 mm Al + 0.1 mm Cu) on image quality and radiation dose was determined for the speed class 400 screen-film system (SFS) and digital luminescence radiography (DLR) by making radiographs of a test phantom. Conventional and digital thorax a.p. radiographs of a rabbit were produced using various tube current-time products. The quality of the rabbit radiographs was judged by eight radiologists applying image quality criteria according to the German guidelines and the recommendations of the European Community. RESULTS: The added filter resulted in a dose reduction of 39% at 66 kV. DLR gave a further dose reduction of 25% in comparison to the speed class 400 SFS while maintaining adequate image quality, i.e. the radiographs were clinically acceptable with regard to quality criteria. CONCLUSION: The radiation dose resulting from thorax a.p. radiographs of neonates can be reduced by approximately 50% with the use of additional filtration and DLR.

Animals↗

PubMed2003

Muscle tetanus and loading condition effects on the elastic and viscous characteristics of the thorax.

Thoracic deformation under an applied load is an established indicator of injury risk, but the force required to achieve an injurious level of deformation currently is not understood adequately. This article evaluates how two potentially important factors, loading condition and muscle tensing, affect the structural response of the dynamically loaded thorax. Structural models of two human cadaver thoraxes and two porcine thoraxes were used to quantify the effects. The human cadavers, which represent anthropometric extremes, were subjected to anterior loading from (1) a 5.1-cm-wide belt oriented diagonally (i.e., seatbelt-like loading), (2) a 15.2-cm-diameter rigid hub, and (3) a 20.3-cm-wide belt oriented laterally (i.e., a distributed load). A structural model having the mathematical formulation of a quasilinear viscoelastic material model was used to model the elastic and viscous response, with ramp-hold tests used to determine the model coefficients. The effect of thoracic musculature was assessed using similar ramp-hold tests on the porcine subjects, each with and without forced muscle contraction. Even maximally contracted thoracic musculature is shown to have a minimal effect on the response, with similar elastic and viscous characteristics exhibited by each subject regardless of muscle tone. The elastic response is shown to be approximately a factor of three stiffer for diagonal belt loading and for this distributed loading condition than for the hub loading, indicating that the response is influenced most by the particular anatomical structures that are engaged and, secondarily, by the area of load application. Specifically, shoulder involvement is shown to have a strong influence. The force relaxation is found to be pronounced, but insensitive to the loading condition, with long-time force relaxation coefficients (G( infinity )) in the range of 0.1 to 0.3. The findings of this study provide restraint-specific guidelines for the force-deflection characteristics of both physical and computational thoracic models.

Animals↗

PubMed1986

The electrical impedance of the human thorax as a guide in evaluation of intrathoracic fluid volume.

The modelling of the human thorax and the impedance characteristics of the thorax are presented. A two-dimensional model of the thorax was constructed by using more than four hundred reference points. The input impedance was calculated by solving the Helmholtz equation for zero charge density and low frequencies. Variation in the impedance corresponds to the fluid in the lung and the degree of inflation, which is related to a given degree of pulmonary oedema.

Humans↗

PubMed2006

Evaluation of intrapulmonary vascular dilatations with high-resolution computed thorax tomography in patients with hepatopulmonary syndrome.

GOALS: We aimed to determine the role of thorax high-resolution computed tomography (HRCT) in demonstrating the pulmonary vasodilatation in patients with hepatopulmonary syndrome (HPS). BACKGROUND: Traditionally, the presence of intrapulmonary vascular dilatations can be detected by using one of the three diagnostic modalities: contrast-enhanced echocardiography, technetium 99 m-labeled macroaggregated albumin scan, and pulmonary angiography. STUDY: The study group included 10 patients with HPS (Group 1), 12 patients with normoxemic cirrhosis (Group 2), and 12 healthy controls (Group 3). All of the subjects underwent conventional and HRCT of thorax. The diameters of pulmonary trunk, main pulmonary arteries, and right lower lobe basal segmental arteries were measured. The ratios of right lower lobe basal segmental pulmonary artery to bronchus diameter were calculated. RESULTS: The mean diameters of the main pulmonary trunk, right and left main pulmonary arteries were not different between the groups. Mean diameters of right lower lobe basal segmental pulmonary arteries were significantly higher in Group 1 compared with Group 2 (P=0.01) and Group 3 (P=0.002). Mean right lower lobe basal segmental pulmonary artery to bronchus ratios were significantly higher in Group 1 compared with Group 2 (P=0.03) and Group 3 (P<0.001). Group 2 had significantly higher pulmonary artery to bronchus ratios than Group 3 (P<0.001). CONCLUSIONS: Thorax HRCT may be helpful in the diagnosis of HPS by demonstrating the dilated peripheral pulmonary vessels or increased pulmonary artery to bronchus ratios in patients with liver disease and hypoxemia.

Adult↗

PubMedDate not supplied

Nerves of the thorax: atlas of normal and pathologic findings.

An anatomic and imaging atlas was created to provide detailed information about the six pairs of thoracic nerves (phrenic nerves, vagus nerves, recurrent laryngeal nerves, sympathetic trunks, costal nerves, long thoracic nerves). Serial axial computed tomographic (CT) scans of the normal thorax were obtained and included in the atlas, along with drawings showing the proper location of each nerve relative to adjacent anatomic structures. CT scans obtained in both symptomatic and asymptomatic patients with various thoracic diseases were paired with appropriate drawings and normal CT scans in the atlas. This format was designed to help determine the presence and severity of related disease, including injury from surgery, trauma, or penetrating injury, metastatic disease involvement, and, rarely, primary tumor. Although the nerves of the thorax are rarely identified at cross-sectional imaging, their location can be inferred by localizing easily identified anatomic landmarks. Familiarity with the functional anatomy and clinical significance of the nerves of the thorax is important for the correct interpretation of thoracic images.

Cadaver↗

PubMed1986

Concepts in computed tomography of the thorax.

A number of concepts in the CT evaluation of the thorax have been reviewed. The concepts have been presented through anatomic images generated on a specific CT system, but any equivalent system could have produced similar images. The important conclusions derived as a result of this review are: 1. Slice thickness, volume averaging and volume sampling are interrelated. Slice thickness and the orientation and inherent subject contrast of the anatomy to be studied usually determine the quality of the image obtained. 2. Thin section imaging (i.e., 5 mm and especially 1.5 mm) can demonstrate thoracic anatomy rarely (if ever) observed on thicker images (i.e., 10 mm). Although impractical for general analysis, thin section imaging provides insight into the potential limitations of a standard approach to thoracic evaluation. 3. CT analysis of the normal anatomy of the pericardium is incomplete. Although pathology related to the pericardium has been presented in the literature, more work is required to define: 1, the relationship, on CT, of the pericardium to structures within its confines; 2, abnormalities within the mediastinum that may affect the pericardium, and 3, lesions in the lung that may invade the mediastinum and pericardium. 4. The excellent contrast sensitivity of CT (aided by iodine infusion or bolus injection techniques and dynamic scanning) does not suffice to resolve certain problems in thoracic analysis. Extrapleural signs, the concept of invasion versus abutment, and the discrimination of benign from malignant mediastinal nodes continue to present diagnostic dilemmas in CT analysis of the thorax. 5. Interesting cases provide models for demonstrating CT pitfalls, mimics, and rarities. CT can be a valuable tool in resolving diagnostic dilemmas in some cases but creates dilemmas in others. 6. CT reformation images of the thorax can be dynamically generated on the scanner console. This hands-on technique can be a valuable tool for teaching anatomy in resident training programs.

Adult↗

PubMed1994

Central bronchiectasis in allergic bronchopulmonary aspergillosis: comparative evaluation of computed tomography of the thorax with bronchography.

Demonstration of central bronchiectasis (CB) with normal peripheral bronchi is an essential requirement for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). Although the results of bronchography remain the gold standard for demonstration of central bronchiectasis they are not always diagnostic. Moreover, it is an unpleasant invasive procedure which may be difficult to perform in a patient of allergic bronchopulmonary aspergillosis with acute severe asthma. In an attempt to find a safe and effective alternative to demonstrate central bronchiectasis computed tomography (CT) of the thorax was evaluated against bronchography. Twenty one patients with allergic bronchopulmonary aspergillosis underwent computed tomography of the thorax followed by bronchography. Of the 378 bronchopulmonary segments available for analysis, 42 had to be excluded because of consolidation or non-filling of the contrast dye, leaving 336 segments for evaluation. CB was identified on CT in all 21 patients. Detailed analysis of the visualized segments revealed that computed tomography (using 8 mm contiguous scans) identified 146 of the 212 segments showing central bronchiectasis on bronchography (sensitivity 70%) and 114 of the 124, read as normal on bronchography (specificity 92%). Supplemental 4 mm scans, used in 8 out of 21 patients improved the overall sensitivity of computed tomography to 83%, whilst the specificity remained unchanged at 92%. Thus, computed tomography of the thorax, being more acceptable to the patient, has the potential of being the investigation of choice for the demonstration of central bronchiectasis in patients with allergic bronchopulmonary aspergillosis.

Adolescent↗

PubMed2001

Thorax and lung injuries arising from the two earthquakes in Turkey in 1999.

STUDY OBJECTIVE: To make a descriptive analysis of the frequency and the type of thorax and lung injuries among the casualties of the two devastating earthquakes that occurred in Turkey in 1999. DESIGN: Records of the hospitalized patients injured in the earthquakes were examined retrospectively. RESULTS: Among the total of 356 hospitalized patients, 21 (9.7%) in the Izmit earthquake and 6 (7.6%) in the Duzce earthquake had thorax and lung injuries. Pneumothorax and rib fractures were the two most frequent pathologies and accounted for 50% and 33.3% of the injuries, respectively. CONCLUSION: Approximately 10% of the casualties of a great earthquake may be expected to have thorax and lung injuries, and traumatic chest diseases should be considered in planning the medical response strategies.

Adolescent↗

PubMed1983

Computed tomography of the thorax. Current perspectives.

With improvement in computed tomography (CT) technology, including faster scanning and images with better detail, the indications for CT of the thorax have expanded. In many instances, data collected on earlier-generation scanners no longer apply. This report is an update of CT scanning of the thorax and includes information on the role of CT in diagnosis when specific clinical syndromes and diseases are suspected. It also addresses controversial subjects, such as the role of CT scanning in the staging of bronchogenic carcinoma and the evaluation of the solitary pulmonary nodule, as well as suggesting guidelines for deciding when a CT scan of the thorax is indicated.

Aortic Dissection↗

PubMed1988

CT densitometry of pulmonary nodules in a frozen human thorax.

The influence of (1) calcium concentration, (2) exposure technique, (3) reconstruction algorithm, (4) nodule size, and (5) nodule location on the CT attenuation values (CT density) of pulmonary nodules was examined in a frozen human thorax. Nodules with calcium concentrations of 0-310 mg/ml and diameters of either 0.95 or 1.59 cm were inserted into a frozen, unembalmed human thorax. The nodules were placed either at the lung apex or 4 cm below the tracheal carina. Each nodule was scanned on a GE CT 9800 scanner; five different exposure techniques were used. The slice thickness was uniformly 1.5 mm. As expected, increasing the kilovoltage caused a significant decrease in CT nodule density in all nodules with calcium concentrations greater than 80 mg/ml. The inverse relationship between kilovoltage and nodule density was exaggerated with increasing calcium concentration. A high-resolution (bone) algorithm gave a significantly higher CT number than did a smoothed (standard) algorithm, regardless of nodule size and location, but this difference could be attributed almost entirely to the edge-enhancement effect of the bone algorithm. The CT density of the larger nodules was significantly higher than that of the smaller nodules at calcium concentrations greater than 65 mg/ml for both standard and bone algorithms. Densities were significantly higher in the mid lung than in the apex with a standard algorithm, but this was not the case with a bone algorithm. The GE CT 9800 scanner had a linear response between CT density and increasing calcium concentration within the confines of a human thorax. A high-resolution (bone) reconstruction algorithm has higher spatial resolution but does show an edge-enhancing effect not found with the smoothed algorithm. Two major variables in CT densitometry for pulmonary nodules are the kilo electron voltage of the X-ray beam and the reconstruction algorithm used; these two parameters should be standardized, with a high kilovoltage and high-resolution algorithm favored on the GE CT 9800 scanner.

Absorptiometry, Photon↗

PubMed2003

[Surgical management of metastatic disease in the conjunctive area between neck and thorax].

OBJECTIVE: To study the surgical management of metastatic disease in the conjunctive area between the neck and thorax and its efficacy. METHODS: Fourteen cases with metastatic node disease in the area between neck and thorax were collected and analysed. Eleven tumors were from the thyroid cancer, and the other three were from the hypopharyngeal cancer, esophagual cancer and malignant pheochromocytoma, respectively. The clavicle was displaced or resected, and the upper half of the manubrium might also be resected when necessary. The recurrent laryngeal nerve and phrenic nerve were exposed and protected. The metastatic disease was completely removed with the internal jugular and/or the brachiocephalic vein resected or spared, depending on the disease condition. RESULTS: In 10 cases with metastases from the thyroid, no local recurrence was found within the follow-up period from 2 to 5 years. In contrast, no patient with metastatic disease from hypopharyngeal or esophageal cancer survived more than 11 months. No serious complications were found in this group. CONCLUSIONS: The surgical treatment of node metastases in the conjunctive area between neck and thorax from the well-developed thyroid cancer has promising effect and is comparatively safe.

Adenocarcinoma, Follicular↗

PubMed2005

The relationship between pulmonary function tests, thorax HRCT, and quantitative ventilation-perfusion scintigraphy in chronic obstructive pulmonary disease.

We have evaluated the relationship between pulmonary function tests (PFT), thorax high resolution computed tomography (HRCT) images and quantitative ventilation-perfusion (V/Q) scintigraphic studies in 16 male patients (mean age 65.6 +/- 5.5 years) with chronic obstructive pulmonary disease (COPD). The mean forced vital capacity (FVC) value of the patient group was 2352 +/- 642 mL (65.4 +/- 15.8%), whereas mean forced expiratory volume in one second (FEV(1)) was found to be 1150 +/- 442 mL (40.8 +/- 14.9%). The ratio of carbon monoxide diffusion capacity to alveolar ventilation (DLCO/VA) was 3.17 +/- 0.88 mL/min/mmHg/L, and the mean partial oxygen (PaO(2)) and carbon dioxide (PaCO(2)) pressures were 68.5 +/- 11.04 mmHg and 38.9 +/- 5.8 mmHg respectively. For each patient, thorax HRCT and V/Q scintigraphic images of both lungs were divided into upper, mid and lower zones during examination. Visual scoring for the assessment of emphysema on thorax HRCT were used and images were graded from mild to severe (< or = 25% - > or = 76%). Emphysema scores were found to be higher on upper zones with accompanying lowest V/Q ratios. DLCO/VA, DLCO, total emphysema scores, and individual emphysema scores of the upper, mid and lower zones were found to be correlated. As a conclusion, it can be stated that emphysematous changes in COPD patients are more apparent in the upper lung zones, which also have the lowest V/Q ratios.

Aged↗