Search

Total marrow radiation is an emerging treatment modality used in patients undergoing stem cell transplantation. We present a rare case of a patient undergoing total marrow irradiation with concurrent ablative stem cell transplantation with local failures in two out-of-field areas that were not included in the clinical target volume A 31-year-old female patient initially presented with abdominal pain secondary to chronic myelogenous leukemia. She underwent dasatinib treatment for years, but subsequently developed recurrence and underwent consolidation systemic chemotherapy followed by allogeneic stem cell transplantation with adjuvant total marrow irradiation. Several months later, she noticed increased left jaw swelling and dysphagia with associated right ankle swelling. Biopsy of the right ankle and left mandible were consistent with recurrent myeloid sarcoma. This case report suggests that inclusion of the mandible and lower extremities may be necessary when performing total marrow radiation.

Radiation (total body irradiation, TBI) combined with chemotherapy plays an important role as a conditioning regimen in patients with hematological malignancies. One of the limitations of TBI, however, has been the toxicity, mainly the pulmonary complications. Hence, maximizing the role of radiation while reducing the dose to limiting organs has been the primary goal of recent efforts. Linear accelerator can deliver conformal radiation dose to the shape of total marrow for patients of hematological malignancies using multileaf collimators and inverse planning techniques. Linac-based intensity-modulated total marrow irradiation (IM-TMI) has shown great potential to reduce severe complications associated with conventional radiation techniques, including TBI through limiting the undesirable dose to organs at risk (OARs). Furthermore, the improved delivery efficiency of volumetric modulated arc therapy (VMAT) can greatly facilitate clinical transition of TMI by providing adequate target coverage with selective normal organ sparing in a more efficient way.

Single‐isocenter volumetric modulated arc therapy (VMAT) technique can provide stereotactic radiosurgery (SRS) treatment with improved delivery efficiency for treating multiple metastases. Nevertheless, planning is time consuming and verification of frame‐based SRS setup, especially at noncoplanar angles, can be challenging. We report on a single‐isocenter VMAT technique with a special focus on improving treatment workflow and delivery verification to exploit the minimized patient motion of the frame‐based SRS. We developed protocols for preplanning and verification for VMAT and evaluated them for ten patient cases. Preplans based on MRI were used to generate comparable treatment plans using CT taken on the day of treatment after frame placement. Target positioning accuracy was evaluated by stereoscopic in‐room kV imaging. Dosimetric accuracy of the noncoplanar plan delivery was validated using measurement‐guided 3D dose reconstruction as well as film‐based end‐to‐end test with a Rando phantom. Average absolute differences of homogeneity indices, conformity indices, and V12Gy between MR preplans and CT‐based plans were within 5%. In‐room imaging positioning accuracy of 0.4 mm was verified to be independent of the distance to the isocenter. For treatment verification, average local and global passing rates of the 3D gamma (1 mm, 3%) were 86% and 99%, respectively. D99 values were matched within 5% for individual target structures (>0.5 cc). Additional film analysis confirmed dosimetric accuracy for small targets that had large verification errors in the 3D dose reconstruction. Our results suggest that the advantages of frame‐based SRS and noncoplanar single‐isocenter VMAT technique can be combined for efficient and accurate treatment of patients with multiple metastases.

Frame‐based stereotactic radiosurgery (SRS) requires fixation of an invasive head ring to ensure accurate targeting. Minimizing waiting time with a fixed head ring is important for patient comfort and satisfaction. We report a practical preplanning solution for the Brainlab iPlan treatment planning system that reduces waiting time by expediting the planning process on treatment day. A water‐filled anthropomorphic head phantom was used to acquire a surrogate CT image set for preplanning and fused with patient's MRI, which was obtained before the day of treatment. Once an acceptable preplan was obtained, it was saved as a plan template and the phantom image set was removed from the Brainlab database to prevent any confusion and mix‐up of image sets. On the treatment day, the patient's CT and MRI were fused, and the customized beam settings of the preplan template were then applied and optimized. Up to 10‐fold of reduction in treatment plan time was demonstrated by bench testing with multiple planners and a variety of cases. Loading the plan template and fine‐tuning the preconfigured beam settings took only a small fraction of the preplan time to restore the conformity and dose falloff comparable to those of the preplan. For instance, preplan time was 2 hr for a two‐isocenter case, whereas, it took less than 20 min for a less experienced planner to plan it on the day of treatment using the preplan method. The SRS preplanning technique implemented in this study for the Brainlab iPlan treatment planning system offers an opportunity to explore possible beam configurations thoroughly, optimize planning parameters, resolve gantry angle clearance issues, and communicate and address challenges with physicians before the treatment day. Preplanning has been proven to improve plan quality and to improve efficiency in our clinic, especially for multiple‐isocenter and dosimetrically challenging cases. PACS number(s): 87.53.Ly, 87.55.D‐, 87.55.Gh, 87.55.tm

The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general‐purpose Monte Carlo code MCNPX (Monte Carlo N‐Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L‐shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (∼1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large‐breasted women. PACS number: 87.53

An integrated Overhauser-enhanced MRI-Prepolarized MRI system was developed to obtain radiobiological information that could be accurately coregistered with diagnostic quality anatomic images. EPR and NMR images were acquired through the double resonance technique and field cycling of the main magnetic field from 5 mT to 0.5 T. Dedicated EPR and NMR coils were devised to minimize radiofrequency power deposition with high signal-to-noise ratio. Trityl and nitroxide radicals were used to characterize oxygen and redox sensitivities of multispin echo Overhauser-enhanced MRI. Oxygen resolution of 3 mmHg was obtained from 2 mM deoxygenated trityl phantoms. Trityl radicals were stable in reducing environments and did not alter the redox-sensitive decaying rate of the nitroxide signals. Nitroxide radicals had a compounding effect for the trityl oximetry. Tumor oxygenation and redox status were acquired with anatomical images by injecting trityl and nitroxide probes subsequently in murine tumors. The Overhauser-enhanced MRI-Prepolarized MRI system is ready for quantitative longitudinal imaging studies of tumor hypoxia and redox status as radiotherapy prognostic factors.

Tumor hypoxia has long been known to produce resistance to radiation. In this study, electron paramagnetic resonance (EPR) oxygen imaging was investigated for its power to predict the success of tumor control according to tumor oxygenation level and radiation dose.A total of 34 EPR oxygen images were obtained from the legs of C3H mice bearing 0.5-cm(3) FSa fibrosarcomas under both normal (air breathing) and clamped tumor conditions. Under the same conditions as those during which the images were obtained, the tumors were irradiated to a variety of doses near the FSa dose at which 50% of tumors were cured. Tumor tissue was distinguished from normal tissue using co-registration of the EPR oxygen images with spin-echo magnetic resonance imaging of the tumor and/or stereotactic localization. The tumor voxel statistics in the EPR oxygen image included the mean and median partial pressure of oxygen and the fraction of tumor voxels below the specified partial pressure of oxygen values of 3, 6, and 10 mm Hg. Bivariate logistic regression analysis using the radiation dose and each of the EPR oxygen image statistics to determine which best separated treatment failure from success.The measurements of the dose at which 50% of tumors were cured were similar to those found in published data for this syngeneic tumor. Bivariate analysis of 34 tumors demonstrated that tumor cure correlated with dose (p = 0.004) and with a10 mm Hg hypoxic fraction (p = 0.023).Our results have shown that, together, radiation dose and EPR image hypoxic fraction separate the population of FSa fibrosarcomas that are cured from those that fail, thus predicting curability.

The authors have obtained spectral-spatial EPRimages of a phantom significantly larger than those previously obtained. Images of a homogeneous phantom 4.2 cm in diameter and 6.5 cm in length with B 1 equivalent to that used for smaller samples give a similar linewidth resolution both with linewidth population distributions of width 0.1 μ T . Spatial resolution appeared to have modest degradation. Images of the large homogeneous phantom provide maps of the magnetic field of a partially shimmed magnet.

Electron paramagnetic resonance imaging (EPRI) can be modeled by the forward projection of a 4D synthetic spectral-spatial phantom. We developed a simulation tool for EPRI and carried out a quantitative comparison between simulation and experiment, focusing on the signal and noise characteristics. The signal height in the simulation was compared to that in the experimental projections at gradients of different magnitudes and directions. We investigated the noise power spectrum of an EPR imager and incorporated it into the simulation. The signal and noise modeling of the simulation achieved the same performance as the EPR imager. Using this simulation, various sampling schemes were tried to find an optimized parameter set under the customized noise model of this EPR imager.

Spectral-spatial imagesreconstructed from a small number of projections suffer from streak artifacts that are seen as noise, particularly in the spectral dimension. Interpolation in projection space can reduce artifacts in the reconstructed images. The reduction of background artifacts improves lineshape fitting. In this work, we compared the performances of angular interpolation implemented using linear, cubic B-spline, and sinc methods. Line width maps were extracted from 4-D EPRimages of phantoms using spectral fitting to evaluate each interpolation method and its robustness to noise. Results from experiment and simulation showed that the cubic B-spline, angular interpolation was preferable to either sinc or linear interpolation methods.

Tumor oxygenation predicts cancer therapy response and malignant phenotype. This has spawned a number of oxymetries. Comparison of different oxymetries is crucial for the validation and understanding of these techniques. Electron paramagnetic resonance (EPR) imaging is a novel technique for providing quantitative high-resolution images of tumor and tissue oxygenation. This work compares sequences of tumor pO2 values from EPR oxygen images with sequences of oxygen measurements made along a track with an Oxylite oxygen probe. Four-dimensional (three spatial and one spectral) EPR oxygen images used spectroscopic imaging techniques to measure the width of a spectral line in each image voxel from a trityl spin probe (OX063, Amersham Health R&D) in the tissues and tumor of mice after spin probe injection. A simple calibration allows direct, quantitative translation of each line width to an oxygen concentration. These four-dimensional EPR images, obtained in 45 minutes from FSa fibrosarcomas grown in the legs of C3H mice, have a spatial resolution of ∼1 mm and oxygen resolution of ∼3 Torr. The position of the Oxylite track was measured within a 2-mm accuracy using a custom stereotactic positioning device. A total of nine images that involve 17 tracks were obtained. Of these, most showed good correlation between the Oxylite measured pO2 and a track located in the tumor within the uncertainties of the Oxylite localizability. The correlation was good both in terms of spatial distribution pattern and pO2 magnitude. The strong correlation of the two modalities corroborates EPR imaging as a useful tool for the study of tumor oxygenation.

Purpose: Tumor microenvironments show remarkable tumor pO_{2} heterogeneity, as seen in prior EPR pO_{2} images (EPROI). pO_{2} correlation with hypoxia response proteins is frustrated by large rapid pO2 changes with position. Procedures: To overcome this limitation, biopsies stereotactically located in the EPROI were used to explore the relationship between vascular endothelial growth factor A (VEGF) concentrations in living mouse tumors and the local EPROI pO_{2}. Results: Quantitative ELISA VEGF concentrations correlated (p = 0.0068 to 0.019) with mean pO_{2}, median pO_{2}, and the fraction of voxels in the biopsy volume with pO_{2} less than 3, 6, and 10 Torr. Conclusions: This validates EPROI hypoxic fractions at the molecular level and provides a new paradigm for the assessment of the relationship, in vivo, between hypoxia and hypoxia response proteins. When translated to human subjects, this will enhance understanding of human tumor pathophysiology and cancer response to therapy.

An integrated Overhauser-enhanced MRI-Prepolarized MRI system was developed to obtain radiobiological information that could be accurately coregistered with diagnostic quality anatomic images. EPR and NMR images were acquired through the double resonance technique and field cycling of the main magnetic field from 5 mT to 0.5 T. Dedicated EPR and NMR coils were devised to minimize radiofrequency power deposition with high signal-to-noise ratio. Trityl and nitroxide radicals were used to characterize oxygen and redox sensitivities of multispin echo Overhauser-enhanced MRI. Oxygen resolution of 3 mmHg was obtained from 2 mM deoxygenated trityl phantoms. Trityl radicals were stable in reducing environments and did not alter the redox-sensitive decaying rate of the nitroxide signals. Nitroxide radicals had a compounding effect for the trityl oximetry. Tumor oxygenation and redox status were acquired with anatomical images by injecting trityl and nitroxide probes subsequently in murine tumors. The Overhauser-enhanced MRI-Prepolarized MRI system is ready for quantitative longitudinal imaging studies of tumor hypoxia and redox status as radiotherapy prognostic factors.

A chest x-ray of 68 year old male showed pneumonic consolidation of right lower lung field with blunting of right cardiac border. Computerized tomography of chest revealed infiltrative mass with V-shaped calcification just below right main bronchus. This finding has to be made into differential diagnosis of numerous pulmonary diseases including, mycobacterial disease, neoplasm, lymphadenopathies, and foreign bodies. Initial bronchoscopic findings suggest endobronchial mass lesion on right intermediate bronchus but endobronchial biopsy fail to prove malignant cell or underlying illness. But repeated endobronchial biopsy shows metallic material in the right Intermediate bronchus and we remove it with alligator jaws forcep under bronchoscopy. He was well after discharge.

Purpose To design and evaluate a magnetic resonance imaging (MRI) protocol to be incorporated in the simulation process for external beam accelerated partial breast irradiation. Methods and Materials An imaging protocol was developed based on an existing breast MRI technique with the patient in the prone position on a dedicated coil. Pulse sequences were customized to exploit T1 and T2 contrast mechanisms characteristic of lumpectomy cavities. A three-dimensional image warping algorithm was included to correct for geometric distortions related to nonlinearity of spatially encoding gradients. Respiratory motion, image distortions, and susceptibility artifacts of 3.5-mm titanium surgical clips were examined. Magnetic resonance images of volunteers were acquired repeatedly to analyze residual setup deviations resulting from breast tissue deformation. Results The customized sequences generated high-resolution magnetic resonance images emphasizing lumpectomy cavity morphology. Respiratory motion was negligible with the subject in the prone position. The gradient-induced nonlinearity was reduced to less than 1 mm in a region 15 cm away from the isocenter of the magnet. Signal-void regions of surgical clips were 4 mm and 8 mm for spin echo and gradient echo images, respectively. Typical residual repositioning errors resulting from breast deformation were estimated to be 3 mm or less. Conclusions MRI guidance for accelerated partial breast irradiation with the patient in the prone position with adequate contrast, spatial fidelity, and resolution is possible.

The authors have obtained spectral-spatial EPR images of a phantom significantly larger than those previously obtained. Images of a homogeneous phantom 4.2 cm in diameter and 6.5 cm in length with B1 equivalent to that used for smaller samples give a similar linewidth resolution both with linewidth population distributions of width 0.1 microT. Spatial resolution appeared to have modest degradation. Images of the large homogeneous phantom provide maps of the magnetic field of a partially shimmed magnet.

Purpose: To compare bone marrow-sparing intensity-modulated pelvic radiotherapy (BMS-IMRT) with conventional (four-field box and anteroposterior‐posteroanterior [AP‐PA]) techniques in the treatment of cervical cancer. Methods and Materials: The data from 7 cervical cancer patients treated with concurrent chemotherapy and IMRTwithout BMS were analyzed and compared with data using four-field box and AP‐PA techniques. All plans were normalized to cover the planning target volume with the 99% isodose line. The clinical target volume consisted of the pelvic and presacral lymph nodes, uterus and cervix, upper vagina, and parametrial tissue. Normal tissues included bowel, bladder, and pelvic bone marrow (PBM), which comprised the lumbosacral spine and ilium and the ischium, pubis, and proximal femora (lower pelvis bone marrow). Dose‐volume histograms for the planning target volume and normal tissues were compared for BMS-IMRT vs. four-field box and AP‐PA plans. Results: BMS-IMRT was superior to the four-field box technique in reducing the dose to the PBM, small bowel, rectum, and bladder. Compared with AP‐PA plans, BMS-IMRT reduced the PBM volume receiving a dose >16.4 Gy. BMS-IMRT reduced the volume of ilium, lower pelvis bone marrow, and bowel receiving a dose >27.7, >18.7, and >21.1 Gy, respectively, but increased dose below these thresholds compared with the AP‐PA plans. BMS-IMRT reduced the volume of lumbosacral spine bone marrow, rectum, small bowel, and bladder at all dose levels in all 7 patients. Conclusion: BMS-IMRTreduced irradiation of PBM compared with the four-field box technique. Compared with theAP‐PAtechnique,BMS-IMRTreduced lumbosacral spine bonemarrowirradiationand reduced thevolumeof PBM irradiated to high doses. ThereforeBMS-IMRT might reduce acute hematologic toxicity comparedwith conventional techniques. 2008 Elsevier Inc. Bone marrow, Bone marrow-sparing, Intensity-modulated radiotherapy, IMRT, Cervical cancer.

Recent advances in electron paramagnetic resonance (EPR) imaging have made it possible to image, in real time in vivo, cells that have been labeled with nitroxide spin probes. We previously reported that cells can be loaded to high (millimolar) intracellular concentrations with (2,2,5,5-tetramethylpyrrolidin-1-oxyl-3-ylmethyl)amine-N,N-diacetic acid by incubation with the corresponding acetoxymethyl (AM) ester. Furthermore, the intracellular lifetime (t(1/e)) of this nitroxide is 114 min-sufficiently long to permit in vivo imaging studies. In the present study, at a gradient of approximately 50 mT/m, we acquire and compare EPR images of a three-tube phantom, filled with either a 200-microM solution of the nitroxide, or a suspension of cells preincubated with the nitroxide AM ester. In both cases, 3-mm resolution images can be acquired with excellent signal-to-noise ratios (SNRs). These findings indicate that cells well-loaded with nitroxide are readily imageable by EPR imaging, and that in vivo tracking studies utilizing such cells should be feasible.

Spectral-spatial images reconstructed from a small number of projections suffer from streak artifacts that are seen as noise, particularly in the spectral dimension. Interpolation in projection space can reduce artifacts in the reconstructed images. The reduction of background artifacts improves lineshape fitting. In this work, we compared the performances of angular interpolation implemented using linear, cubic B-spline, and sinc methods. Line width maps were extracted from 4-D EPR images of phantoms using spectral fitting to evaluate each interpolation method and its robustness to noise. Results from experiment and simulation showed that the cubic B-spline, angular interpolation was preferable to either sinc or linear interpolation methods.

For spectral-spatial EPR imaging, prior knowledge about the spatial support of an imaged object can be exploited in two ways. We can shrink the spatial field of view (FOV) to closely wrap the object in a sphere or reduce the sweep width in a projection dependent fashion. Use of a smaller spatial FOV with the same number of samples enhances spatial resolution by reducing voxel volume at the expense of signal-to-noise and a consequent degraded line width resolution. We have developed another approach to define sweep width that prunes away the portions of the projection sweep with no signal. This reduces data acquisition time for the continuous wave (CW) EPR image proportional to the sweep width reduction. This method also avoids voxel volume reduction. Using the reduced-sweep method, we decreased the data acquisition time by 20% maintaining spatial and linewidth resolution.

Four-dimensional EPR imaging involves a computationally intensive inversion of the sampled Radon transform. Conventionally, N-dimensional reconstructions have been carried out with N-1 stages of 2-D backprojection to exploit a dimension-dependent reduction in execution time. The huge data size of 4-D EPR imaging demands the use of a 3-stage reconstruction each consisting of 2-D backprojections. This gives three orders of magnitude reduction in computation relative to a single stage 4-D filtered backprojection. The multi-stage reconstruction, however, requires a uniform angular sampling that yields an inefficient distribution of gradient directions. We introduce a solution that involves acquisition of projections uniformly distributed in solid angle and reconstructs in three 2-D stages with the spatial uniform solid angle data set converted to uniform linear angular projections using 2-D interpolation. Images were taken from the two sampling schemes to compare the spatial resolution and the line width resolution. The degradation in the image quality due to the additional interpolation was small, and we achieved approximately 30% reduction in data acquisition time.

Purpose: To develop a multi‐parametric molecular imager to assess tumor hypoxia and redox status by integrating Overhauser‐enhanced MRI (OMRI) with prepolarized MRI (PMRI). Method and Materials: PMRI system acquires anatomic MR images comparable to conventional MRI. With a moderate hardware augmentation of the PMRI, we implemented field‐cycled OMRI and obtained electron paramagnetic resonance(EPR)images of nitroxide spin probes. Phantoms were made of 2‐cc tubes filled with pure water

Tumor oxygenation and redox status are important determinants of the malignant behavior of cancers and their response to radiation therapy. Concentration of molecular oxygen is directly related to the generation of non‐restorable DNA damage. Tissueredox status indicates catalytic cellular activities to scavenge free radicals that initiate a chain of events for DNA damage by an ionizing radiation. Thus a non‐invasive system that obtains this information on relevant time scales with anatomical context could facilitate longitudinal studies of the multi‐faceted tumor environment. Changes in the resonant properties of exogenous narrow‐line electron spin (free radical) probes in presence of oxygen can be sensed by electron paramagnetic resonance as well as Overhauser‐enhanced magnetic resonance (OMR). In OMR, the dipolar interaction between protons and the unpaired electron of the spin probe results in strong increase of the protonMR signal. The enhancement depends on several factors such as spin probe and oxygen concentration, longitudinal relaxation times, and the magnitude of the radiofrequency magnetic field that manipulates the electron spins. Specific imaging sequences decoupling these factors in spatially encoded manner can generate quantitative spatial maps not only of tumor oxygenation but also micro‐vascular parameters. Furthermore, these physiological maps can be natively fused with anatomical MRimages generated with the same hardware in the same imaging session. This information can be acquired repeatedly for quantitative longitudinal imaging experiments to explore both oxygenation and redox status in small animals as prognostic factors for radiation therapy. Learning objectives: 1. Understand the basic physics behind the Overhauser enhancement and enumerate the factors that determine its magnitude. 2. Recognize the main hardware components of an Overhauser oxygenation imager and understand the operating parameters of the imaging system in contrast to these of high‐field diagnostic MR scanner. 3. Understand a typical OMR imaging sequence and subsequent image analysis to derive oxygenation maps. 4. Understand typical OMRI applications in cancer‐related studies.

Purpose: It is important to deliver an optimized dose distribution to an accurately delineated target volume for a successful accelerated partial breast irradiation (APBI) treatment. Breast magnetic resonance imaging(MRI) could improve lumpectomy delineation. We investigated treatment plans for CyberKnife and conventional C‐arm LINAC delivery of MRI‐guided APBI in prone position. Method and Materials: We acquired a CT scan of a patient positioned on a mechanical assembly with the same geometry as the dedicated MR coil to simulate the position during breast MRI acquisition. Ellipsoidal virtual PTV's of 4 cm were defined in the anterior part and in the lower outer quadrant of the right breast. Treatment plans were generated by inverse planning techniques for each system. For CyberKnife, we minimized beam directions from posterior to anterior to protect critical normal tissues(heart,lung and contralateral breast) and normalized the maximum dose to 120% of the prescription dose (38.5 Gy). For the conventional LINAC, we excluded any beams directed towards the critical normal tissues and normalized the plan to achieve 99% of the prescription coverage for 99% of PTV. Results: LINAC‐based plans resulted in maximum doses of 41.6 Gy in PTV and ⩽ 0.5 Gy in the critical normal structures. CyberKnife‐based plans led to 90% of the prescription dose coverage for 95% of PTV. Maximum doses were ⩽ 0.5 Gy in contralateral breast, ⩽ 1.9 Gy in heart, and ⩽ 4.2 Gy in both lungs. The fraction of normal ipsilateral breast tissue receiving ⩾ 37 Gy was 1% and 5% for CyberKnife and LINAC plans respectively. Conclusion: CyberKnife and LINAC generate treatment plans for MRI‐guided prone position APBI with acceptable dose distributions. The standard LINAC requires careful beam configuration to secure clearances between equipments. CyberKnife results in better conformity and slightly higher doses in the critical normal tissues.

Purpose: Accurate delineation of tumor bed is prerequisite for an effective treatment of breast cancer with accelerated partial breast irradiation (APBI) technique. Magnetic resonance imaging(MRI) has high contrast mechanisms that could enable precise contouring of the lumpectomy cavity. We investigated practical issues pertinent to MR‐guided breast radiation therapy using customized pulse sequences. Method and Materials: Unilateral breast MRimages were obtained from two healthy volunteers in prone position on a dedicated coil. Radiation therapists positioned the volunteers in reproducible setup using a waterproof marker. We acquired 6‐min 3D MRimages to analyze setup uncertainty and fast 2D MRimages of 0.5‐s temporal resolution to detect respiratory motion. An accurate 3D warping‐correction algorithm was evaluated and used to restore spatial fidelity from geometric distortions due to MR gradient non‐linearities. MRimages of surgical clips as fiducial were obtained using pulse sequences designed to provide high signal from lumpectomy cavity. Results: Average breathing motion in the breast was found to be less than 0.5 mm in prone position. Setup deviations of 1 cm were observed between series of intended prone positioning. Rigid image registration based on local anatomy structure resulted in a residual error which was up to 5 mm at the peripheral region of the breast. Gradient‐induced non‐linearity led to 1 cm distortion in the uncorrected phantom image at the region 15 cm away from the main magnet axis. The 3D correction algorithm reduced the deviation to < 1 mm. We observed 4 mm signal void artifacts of surgical clips. Conclusion: We obtained MRimages of suitable quality from volunteers using pulse sequences customized for lumpectomy site identification. MR‐guided APBI in prone position would require 5 mm uniform expansion of clinical target volume with the employment of an appropriate on‐board imaging technique.

Purpose: To compare bone marrow‐sparing intensity modulated pelvic radiation therapy (BMS‐IMRT) to conventional (AP/PA and 4‐field box) techniques in the treatment of cervical cancer.Method and Materials: Seven cervical cancer patients treated with concurrent chemotherapy and IMRT were analyzed. We compared BMS‐IMRT to AP/PA and 4‐field box plans. All plans were normalized to cover PTV with the 99% isodose line. The clinical target volume (CTV) consisted of the pelvic and presacral lymph nodes, uterus and cervix, upper vagina, and parametrial tissue. A 1.0 cm uniform margin was added to create the PTV. Normal tissues included bowel, bladder, and pelvic bone marrow (PBM), which comprised the lumbosacral spine (LSBM), ilium (IBM), and ischium, pubis, and proximal femora (lower pelvis bone marrow — LPBM). Dose volume histograms for PTV and normal tissues were compared for BMS‐IMRT vs. 4‐field box and AP/PA plans. Results: BMS‐IMRT was superior to 4‐field box in reducing the dose to PBM, small bowel, rectum and bladder. Compared to AP/PA, BMS‐IMRT reduced the PBM volume receiving a dose above 16.4 Gy, however, that receiving below this threshold dose was increased. BMS‐IMRT reduced IBM, LPBM and bowel radiation above 27.7 Gy, 18.7 Gy, and 21.1 Gy, respectively, but increased dose below these thresholds, compared to AP/PA plans. BMS‐IMRT reduced the volume of LSBM, rectum, small bowel, and bladder at all dose levels in all 7 patients. Conclusion: BMS‐IMRT reduced irradiation of PBM compared to 4‐field box techniques. Compared to AP/PA, BMS‐IMRT reduced LSBM irradiation and reduced the volume of PBM irradiated to high doses, but increased that irradiated to low doses. BMS‐IMRT may reduce acute HT compared to conventional techniques.

A thromboembolic event in patients later given a diagnosis of cancer is the result rather than the cause of the cancer. The risk of hidden cancer is significantly higher for patients with recurrent idiopathic thromboembolism compared to those with secondary deep vein thrombosis. Microemboli from hepatic or adrenal metastases and large-sized emboli from the great veins invaded by the tumor are the sources of tumor embolization The intraarterial tumor emboli less likely invade the arterial wall. Thrombus formation and organization may be capable of destroying tumor cells within pulmorlary blood vessels. Therefore, all tumor emboli are not true metastases. The treatment of deep vein thrombosis and pulmonary embolism in patients with cancer consists of anticoagulation with heparin and warfarin, venacaval filters, appropriate anti-neoplastic agents, and surgical methods(embolectomy, thromboendarterectomy). However, considerable literatures suggest that oral anticoagulant such as warfarin is ineffective in the treatment of those. We report a case of primary unknown squamous cell carcinoma incidentally found in the thrombus after pulmonary embolectomy.

Background: Resting pulmonary function tests(PFTs) are routinely used in the evaluation of pulmonary impairment/disability. But the significance of the cardiopulmonary exercise test(CPX) in the evaluation of pulmonary impairment is controvertible. Many experts believe that dyspnea, though a necessary part of the assessment, is not a reliable predictor of impairment. Nevertheless, oxygen requirements of an organism at rest are different from at activity or exercising, and a clear relationship between resting PFTs and exercise tolerance has not been established in patients with chronic pulmonary disease. As well, the relationship between resting PFTs and dyspnea is complex. To investigate the relationship of dyspnea, resting PFTs, and CPX, we evaluated the patients of stabilized chronic pulmonary disease with clinical dyspnea rating(baseline dyspnea index, BDI), resting PFTs, and CPX. Method: The 50 patients were divided into two groups: non-severe and severe group on basis of results of resting PFTs(by criteria of ATS), CPX(by criteria of ATS or Ortega), and dyspnea rating(by focal score of BDI). Groups were compared with respect to pulmonary function, indices of CPX, and dyspnea rating. Results: 1. According to the criteria of pulmonary impairment with resting PFTs, max, and focal score of BDI were significantly low in the severe group(pmax(ml/kg/min) and max(%), the parameters of resting PFTs, except were not significantly different between non-severe and severe(p>0.05). According to focal score((%), FVC(%), MW(%), , and max were significantly lower in the severe group(pmax(ml/kg/min) and max(%) were low(p(%) was correlated with max(%)(r=0.52;pmax and max WR. Therefore, if not contraindicated, CPX would be considered to evaluate the severity of pulmonary impairment in patients with chronic pulmonary diseases, including with severe resting PFTs. Current criteria used to evaluate the severity of impairment were insufficient in considering the degree of dyspnea, so new criteria, including the severity of dyspnea, may be necessary.

연구배경: 결핵의 유병률은 감소하는 추세이나 노인, 항암약물요법, HIV 감염 풍에 의해 면역기능이 약화된 환자에 있어서 결핵의 발생이 문제가 되고 있으며, 특히 다제내성균주의 출현은 큰 문제이다. 결핵진단법 중 체액에서 도말검사나 배양검사를 통해서 Myco-bacterium tuberculosis를 검출하는 것이 표준진단법이나, 도말검사는 상대적으로 민감도가 낮고 배양검사는 오랜시간이 소요된다. 중함연쇄반응을 이용하여 결핵균의 DNA를 검출하는 방법은 매우 민감하나 비용이 많이 소요된다. ELISA(enzyme linked immunosorbent assay)를 이용하여 혈청에서 결핵균 특이항원에 대한 항체를 검출하는 방법이 객담도말음성인 활동성 폐결핵환자를 다른 비결핵성 폐질환으로부터 감별하는데 유용한지를 확인하고자 하였다. 방 법: 연세대학교 세브란스 병원에 입원한 183명의 객담도 말음성인 폐질환환자에서 항산균에 대한 객담도말 및 배양검사와 결핵균 특이 항원인 recombinant 38 kilo-dalton 항원과 culture filtrate항원을 이용한 ELISA 검사를 시행하였다. 결 과: 35명의 활동성 폐결핵환자 중 18명에서 배양검사상 Mycobacterium tuberculosis를 검출할 수 있었다. 38 kDa와 culture filtrate에 대한 흡광도는 활동성 폐결핵환자들에서 비결핵성 폐질환자들보다 유의하게 높았다 (p 0.05) 객담도말음성인 환자에 있어서 38 kDa과 culture filtrate의 민감도는 각각 20.0%와 31.4%였고 특이도는 각각 95.3%와 93.9%였다. 결 론: 객답도말검사 음성인 활동성 폐결핵환자에 있어서 ELISA를 이용한 38 kDa과 culture filtrate 항원에 대한 혈청항체검사법은 기존진단방법보다 낮은 민감도를 보여, 비결핵성 폐질환으로부터 활동성 폐결핵을 감별진단하는데 크게 도움이 되지 않을 것으로 여겨진다. 【Background: Diagnosis by direct microscopy and/or by culture of the Mycobacterium tuberculosis from body fluids or biopsy specimens is "Gold standard". However, the sensitivity of direct microscopy after Ziehl-Neelsen staining is relatively low and culture of mycobacteria is time consuming. Detection of mycobacterial DNA in clinical samples by the polymerase chain reaction is highly sensitive but laborious and expensive. Therefore, rapid, sensitive and readily applicable new tests need to be developed. So we had evaluated the clinical significance of serologic detection of antibody to 38 kDa antigen, which is known as the most specific to the M. tuberculosis complex, and culture filtrate antigen by ELISA in sputum AFB smear negative patients. Method: In this study, culture tests for acid fast bacilli with sputa or bronchial washing fluids of 183 consecutive patients who were negative of sputum AFB smear were performed. Simultaneously serum antibodies to 38 kDa antigen and unheated culture filtrate of M. tuberculosis were detected by an ELISA method. Results: The optical densities of ELISA test with 38 kDa and culture filtrate antigen were significantly higher in active pulmonary tuberculosis cases than in non tuberculous pulmonary diseases (p 0.05). In the smear-negative active pulmonary tuberculosis patients, the sensitivity of the ELISA using 38 kDa antigen and culture filtrate was 20.0% and 31.4%. respectively. The specificity was 95.3% and 93.9%. respectively. Conclusion : In active pulmonary tuberculosis but smear negative, the serologic detection of antibody to 38 kDa antigen and culture filtrate by ELISA cannot substitute traditional diagnostic tests and does not have clinically significant role to differenciate the patient with active pulmonary tuberculosis from other with non-tuberculous pulmonary diseases.】

Background: Most of malignant pleural effusions are serous but 8-33% of them are bloody. We wanted to evaluate the relationships between gross appearance and pleural CEA level or results of histocytology in malignancy associated pleural effusions. We also tried to reevaluate the meaning of CEA measurement in histocytologically proved or unproved malignancy associated pleural effusions. Methods: We studied 98 cases of malignancy associated pleural effusions, 50 cases of histocytologically proven malignant effusions and 48 cases of histocytologically unproven paramalignant effusions. We had observed gross appearance and conventional laboratory values and CEA levels for pleural effusions. Results: 44.9% of malignancy associated effusions were bloody(63.6% of bloody effusions were histocytologically proven malignant effusion). 65.0% of malignancy associated pleural effusions which have RBCs numbers over were cytologically proven malignant effusions. 72.7% of cytologically proven malignant effusions had increased pleural fluid CEA level over 10 ng/ml. 58.2% of cases with pleural CEA over 10 ng/ml had positive results in pleural bistocytology. There was no definable relationships between pleural fluid CEA elevation and RBCs numbers and results of pleural fluid cytology. Conclusion: About half of the cases with malignancy associated pleural effusions were bloody. Histocytologically proven malignant effusions were more common in bloody effusion than non-bloody effusion(63.6% Vs 38.9%). But increased red blood cell numbers was not associated with positivity of pleural histocytology. Pleural fluid CEA elevation(over 10 ng/ml) was not correlated with positive pleural histocytology. But pleural fluid CEA elevation was rare in nonmalignant pleural effusions, and than pleural CEA measurement in uncertain pleural effusions maybe helpful to distinguishes its origin.

Background: Transcather arterial embolization has been established as an effective means to control hemoptysis, especially in patients with decreased pulmonary function such as postpneumonectomy patients and those with advanced chronic obstructive pulmonary disease. We evaluated the effect of arterial embolization and analysed the correlation of the clinical and angiographic characteristics and investigated the clinical course and outcome after arterial embolization in the patients with significant hemoptysis. Method: 58 patients with massive or recurrent hemoptysis underwent transcatheter arterial embolization for the treatment of hemoptysis from April 1992 to Sept. 1993. Results: Most common cause of hemoptysis was pulmonary tuberculosis(34 cases, 58.3%). Embolized vessels responsible for hemoptysis were 56 bronchial arteries and 32 nonbronchial systemic arteries. Initial most common angiographic findings were hypervascularity and shunt. Initial success rate of hemoptysis control revealed 81.1%. However, 15 of 58 patients(25.9%) showed recurrence of hemoptysis after transcatheter arterial embolization. The complications(18 cases, 31%) such as chest pain, fever, voiding difficulty, atelectasis, paralytic ileus and unwanted embolization were occured. Conclusion: Transcatheter arterial embolization is useful and relatively safe treatment modality for immediate bleeding control of patients with massive hemoptysis or inoperable cases. The further evaluation of the long term results according to the embolized material and underlying pulmonary disease will be required.

Histiocytosis-X is a tenn used to define three diseases with similar morphologic characteristics : Letterer-Siwe diseae, Hand-Schuller-Christian disease and Eosinophilic granuloma. In general, they differ in terms of their age of onset, severity of clinical course and site of involvement. Eosinophilic granuloma typically is seen in young adults. Eosinophilic granuloma is diagnosed in the presense of diffuse pulmonary infiltrate, bony involvement. However, the pulmonary radiologic findings of eosinophilic granuloma are variable accordinary to stage of disease. therefore pathologic diagnosis of involving site is essential for confirmative diagnosis of eosinophilic grananuloma. Pathologically. the three disease are characterized by granulomatous infiltration of alveolar septa and bronchial walls and often involvement of bone. The hallmark of this disease is proliferation of the Langerhans' cell. The identifying feature is the X-body or Birbeck granule that is present in Langerhans' cells and histiocytic cells found in the lung of EG patient. We report a case of bilatera1, recurrent and spontaneous pneumothoraces in a 21 year old man with pulmonary histiocytosis-X, which is confirmed by eosinophilc granuloma in bone marrow biopsy and ultrastructural examination in cells obtained from BAL.

The leiomyosarcoma is uncommon tumor that consists of 10% of all sarcoma incidence and commonly arise from retroperitoneum or mesentery. But leiomyosarcoma arose from mediastinum is very rare and only incidental case report is present. Mediastinal leiomyosarcoma may originate from superior vena cava, pulmonary artery, small vessels of alveoli, esophagus and cardiac muscle. Common symptoms that are related with leiomyosarcoma of mediastinum are cough and dyspnea but dysphagia, chest pain and hemoptysis can be produced. Although long term survival after complete resection of tumor was reported in localized disease, there was no effective therapy that prolong the survival in patients who had disseminated disease or huge tumor mass. We report the case of posterior mediastinal leiomyosarcoma confirmed by aspiration cytology and immunohistochemical staining, along with a review of literature.