Biomedical subjects

C Fellner

Publications and source records attributed to C Fellner.

At least 19 recordsLinked to original sources

PubMed2002

Hyperintense and hypointense MRI signals of the precentral gyrus and corticospinal tract in ALS: a follow-up examination including FLAIR images.

In amyotrophic lateral sclerosis (ALS) patients, hyperintense signals at the subcortical precentral gyrus in brain fluid attenuated inversion recovery (FLAIR) MR images have been found more frequently than in controls. Quantitative analysis has revealed a significant increase of the FLAIR-magnetic resonance imaging (MRI) signal at the subcortical precentral gyrus of ALS patients compared to healthy controls. In addition, hypointense signals at the rim of the precentral gyrus in FLAIR and T2-weighted images have been shown in ALS patients. In 17 ALS patients, we evaluated hyperintense signals in T2-, T1-, proton density-weighted and FLAIR MR images, and hypointense signals in T2-weighted and FLAIR images 15.7+/-3.0 months after the initial examination by visual scoring. In FLAIR images, a quantitative analysis was added. The visual scores of hyperintense signals along the corticospinal tract did not change significantly in all sequences. However, the quantitative evaluation of FLAIR images revealed a significant increase of the signal intensity at the subcortical precentral gyrus (p<0.005). In addition, the frequency of the visually evaluated hypointense signals at the precentral gyrus increased significantly (p<0.05). The change of MR results did not correlate with the change of clinical parameters. In ALS patients, the increase of the quantified MRI signal at the subcortical precentral gyrus in FLAIR images and the increase of hypointense signals at the rim of the precentral gyrus corroborate the hypothesis that these signals are related to the upper motor neuron degeneration in ALS. Their specificity and clinical relevance have to be clarified further.

Adult↗

PubMed2001

MRI-FLAIR images of the head show corticospinal tract alterations in ALS patients more frequently than T2-, T1- and proton-density-weighted images.

In some patients with amyotrophic lateral sclerosis (ALS), T2-weighted and proton-density-weighted magnetic resonance imaging (MRI) shows hyperintense or hypointense signals at the corticospinal tract. Fluid-attenuated inversion recovery (FLAIR) sequences increase the sensitivity of MRI to detect cortical and subcortical tissue changes. In 31 ALS patients and 33 controls, we studied the frequency and the extent of signal abnormalities in FLAIR images compared to T2-, T1- and proton-density-weighted images. Hyperintense signals at the corticospinal tract were significantly more frequent in FLAIR images than in all other tested sequences. In FLAIR images of ALS patients only, distinct hyperintense signals at the subcortical precentral gyrus (five patients), the centrum semiovale (eight patients), the crus cerebri (nine patients) and the pons (four patients) as well as mild hyperintense signals in the medulla oblongata (three patients) were seen. More frequently, but not exclusively in ALS patients, FLAIR images showed mild hyperintense signals at the subcortical precentral gyrus (15 patients vs. 1 control). Quantitative analysis confirmed the significant difference between ALS patients and controls at the subcortical precentral gyrus in FLAIR images. In T1-weighted images, the corticospinal tract at the capsula interna was hypointense in significantly more controls than ALS patients. Also this difference was confirmed in the quantitative analysis. Similar to previous results, MR image alterations did correlate poorly to clinical data of upper motor neuron affliction.MR images of the head, including FLAIR images, provide additional information regarding corticospinal tract involvement in ALS patients. Because of an overlap with physiological findings, they have to be interpreted cautiously, with the exception of hyperintense signals at the subcortical precentral gyrus.

Adult↗

PubMed2001

[MRI-assisted brachytherapy of nonresectable liver metastases. Preliminary technical and clinical experiences].

PURPOSE: To evaluate the feasibility and efficacy of MR-guided interstitial brachytherapy of non-resectable liver metastasis. METHODS: Liver metastases (0.8-5.2 cm in diameter) were treated during a prospective phase I/II study using an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen). MR-compatible brachytherapy applicators were placed percutaneously under MR-guidance in an open 0.2 Tesla MR system (Magnetom Open Viva, Siemens, Erlangen) using fast T1-weighted sequences. Pretreatment and follow-up studies were performed using a 1.5 Tesla MR system. RESULTS: Preliminary results of an unpublished prospective study are discussed exemplary on 2 selected patients. The median procedure time was 4.9 h. No major complications were observed and late effects were acceptable. In large symptomatic metastases only a temporary relief of pain was achieved. In smaller metastases (DM 3 cm) a tumor control was observed. CONCLUSION: MR-guided brachytherapy is feasible and has the potential to ablate liver metastases with diameter of less than 3 cm. Further developments are necessary.

Adenocarcinoma↗

PubMed2001

Comparison of radiography- and computed tomography-based treatment planning in cervix cancer in brachytherapy with specific attention to some quality assurance aspects.

INTRODUCTION: A modern approach in treatment planning for cervix carcinoma is based on a series of computed tomography (CT) sections and 3D dose computation. When these techniques were not yet available, dose evaluation was based on orthogonal radiographs. The CT based planning provides information on target and organ volumes and dose-volume histograms. The radiography based planning provides only dimensions and doses at selected points. The aim of the presented study is to correlate the information obtained with the two approaches for high dose-rate (HDR) brachytherapy of cervix carcinoma. METHODS: For the study 28 patients with 35 applications receiving HDR treatment with Ir-192 were investigated. The planning system PLATO (Nucletron) was used. The different aspects of available data, results and inaccuracies regarding quality assurance were looked at. RESULTS: From the CT based planning, the volume, location and dose-volume histograms were calculated for the CTV, rectum and bladder. From the radiography-based planning, the dose to point A (prescription), point B, rectum and bladder ICRU reference points [14], points related to the bony structures could be evaluated as well as volumes receiving different dose levels. These two sets of information were compared and following mean values derived. For a dose prescription of 7 Gy at point A, as an average, 83% (44 cm(3)) of the clinical target volume (CTV) receives at least 7 Gy. The mean dose at the rectum ICRU reference point is 4.3 Gy, and 12% (9 cm(3)) of the rectum is encompassed by the 4.3 Gy isodose. The mean dose at the bladder ICRU reference point is 5.8 Gy, and 8% (16 cm(3)) of the bladder is encompassed by the 5.8 Gy isodose. The maximum dose to the rectum is 1.5 times higher than the dose at the ICRU reference point, and for the bladder 1.4 times higher. Uncertainties caused by the reconstruction of the applicator and merging of isodoses could be evaluated. DISCUSSION: The subdivision of different approaches and the transfer from point doses to volumes in treatment planning is possible and practical for the treatment of cervix carcinoma in brachytherapy.

Brachytherapy↗

PubMed2001

Prescribing, recording, and reporting in endovascular brachytherapy. Quality assurance, equipment, personnel and education.

Endovascular brachytherapy is a new, rapidly growing field of interest in radiotherapy for the prevention of neointimal hyperplasia after angioplasty in both coronary and peripheral arteries. Many physics aspects of these treatments have already been addressed in the report of the American Association of Physicists in Medicine task group on 'Intravascular brachytherapy', but up to now there are no generally accepted recommendations for recording and reporting radiation doses and volumes. The terminology to be used by all individuals involved in such treatments (radiation oncologists, physicists, and interventionalists) is not clearly defined. The Endovascular Groupe Européen de Curiethérapie/European Society for Therapeutic Radiology and Oncology Working Group in this document presents recommendations for a common language for general use in endovascular brachytherapy. This proposal addresses general terms and concepts for target and dose specification as well as detailed recommendations for dose prescription, recording and reporting in endovascular brachytherapy for both peripheral and coronary arteries. Additionally, quality assurance and radiation safety aspects are briefly addressed, as are aspects related to equipment, personnel, and training and education related to endovascular brachytherapy.

Brachytherapy↗

PubMed2001

A high-resolution phantom for MRI.

Assessment of spatial resolution is an important step to test the performance of new sequence techniques-especially ultrafast techniques with dedicated k-space trajectories or interpolation algorithms. Measurement of the modulation transfer function (MTF) is a rather difficult procedure, but using suitable resolution phantoms allows a simple visual evaluation of spatial resolution. In contrast to commonly used test objects with a very restricted number of resolution patterns we developed a phantom containing resolution patterns from 0.1 to 1.5 mm in steps of 0.1 mm. One resolution pattern consists of five parallel Plexiglas strips with the distance of the strips being equal to their thickness. Together with a Plexiglas cuboid the resolution patterns are mounted on a Plexiglas plate on the bottom of the cylindrical phantom. An aqueous solution of manganese chloride is used to fill the phantom. High resolution cross sections (pixel size: 50 microm) through the resolution patterns were measured to confirm the correct dimensions of the phantom. To verify the appropriateness of the 0.1 and 0.2 mm stacks micro-CT images with a pixel size of 25 microm were acquired additionally for both patterns. Besides visual inspection evaluation of the profile function of signal intensity across the stacks demonstrates that the resolution patterns are sufficiently correct. T(1)-weighted SE sequences with slightly different pixel sizes as well as T(1)- and T(2*)- weighted gradient echo sequences were applied to demonstrate some possible applications of this phantom. In conclusion, the proposed phantom is well suited to assess the spatial resolution qualitatively (i.e., visually) and quantitatively over a wide range in steps of 0.1 mm.

Humans↗

PubMed2001

Direct MR arthrography of the shoulder: 2D vs. 3D gradient-echo imaging.

The aim of this study was to determine the value of a fat suppressed 3D gradient-echo sequence (GRE) data set in comparison to a 2D GRE sequence in direct MR arthrography of the shoulder. For this purpose we examined 50 consecutive patients with subacute or chronic disorders of the shoulder using a 1.5 T scanner: Transverse T1-weighted 2D (slice thickness 4 mm) and 3D GRE (slice thickness 1.5 mm reconstructed from 3 mm), oblique coronal T2- and T1-weighted turbo spin-echo (TSE) and sagittal T1-weighted TSE with fat saturation were applied. Visual image analysis of anatomical and pathological structures was performed by two independent observers. A correlation to surgical results was available in 21 patients. Transverse GRE sequences were well suited for analysis of the anterior/posterior labrum, the middle glenohumeral ligament, and cartilage. 3D GRE with fat suppression was slightly superior to 2D GRE without fat suppression in the evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament, whereas for cartilage no significant differences were found between both sequences. Concerning pathological findings, in most of the cases 2D delivered the same results as 3D. In conclusion, a T1-weighted 3D GRE data set with fat saturation in transverse orientation may be useful for evaluation of the anterior/posterior labrum, and the middle glenohumeral ligament. However, similar measured slice thickness of 3 mm-even if interpolated to 1.5 mm-compared to a 2D sequence with 4 mm does not provide significant diagnostic advantages.

Adolescent↗

PubMed2001

Endovascular brachytherapy for prophylaxis against restenosis after long-segment femoropopliteal placement of stents: initial results.

PURPOSE: To evaluate the feasibility, safety, and effectiveness of endovascular brachytherapy for the prevention of restenosis after long-segment femoropopliteal percutaneous transluminal angioplasty (PTA) and stent implantation. MATERIALS AND METHODS: Thirty-three patients (23 men, 10 women; mean age, 66 years) with femoropopliteal lesions (mean treated length, 17 cm; range, 4-30 cm) underwent PTA and stent implantation followed by brachytherapy with a centering catheter. A dose of 14 Gy was delivered to the adventitia by using an iridium 192 source. Long-term pharmacotherapy with acetylsalicylic acid was combined with clopidogrel for 1 month. Follow-up examinations included measurement of the ankle-brachial index, color-coded duplex ultrasonography, and angiography. RESULTS: The overall 6-month recurrence rate was 30% (10 of 33 arteries). Seven patients developed sudden late thrombotic occlusion of the segment with the stent 3.5-6 months after stent implantation. Considering the overall results after successful local thrombolysis in six of these seven patients, only four (12%) of 33 arteries with a stent had in-stent restenosis caused by neointimal hyperplasia. CONCLUSION: The study results are promising concerning the possibility of reducing in-stent restenosis by means of brachytherapy after long-segment femoropopliteal placement of stents. The high incidence of late thrombotic occlusion requires optimization of the antithrombotic regimen.

Aged↗

PubMed2001

Pneumatic bracing and total contact casting have equivocal effects on plantar pressure relief.

The purpose was to examine and compare plantar pressures produced in healthy subjects while wearing a running shoe (RS), total contact cast (TCC) and 'customized' pneumatic pre-fabricated walking brace (PWB). A repeated measures design was used to compare the plantar pressures recorded for three footwear types (RS, TCC, PWB) in two body regions (forefoot, heel). Nine healthy subjects walked at a self-selected walking pace on a motorized treadmill while wearing the RS, TCC and PWB (ordered randomization). Following a five-minute acclimatization period on the treadmill with each footwear device, plantar pressures were recorded from 84 constant gait speed and step length steps using the Pedar system of in-shoe array of capacitive sensors embedded in an insert. Mean spatially averaged peak plantar pressures were recorded for the metatarsal heads and heel region for each footwear device worn by each subject. A two-way analysis of variance with repeated measures and post-hoc Tukey tests analysed the data with a significance level of p=.05. The main effects of footwear (p=.005) and body region (p=.000), and interaction effect (body region x footwear device) (p=.000) were significant. Unloading of the forefoot was 63.72% and 58.77% for the TCC and PWB, respectively, whereas loading under the heel was increased 37.09% and 34.11% for the same two devices, respectively. Patients who develop neuropathic plantar ulcers in the forefoot region, but not in the heel region, may benefit from a reduction in plantar pressures by using either the TCC or a 'customized' PWB. An alternative footwear device still needs to be found for those patients with heel ulceration.

Adult↗

PubMed2001

A low-field MR system in acute traumatological imaging in radiology. Technical note.

PURPOSE: In this paper initial clinical observations with the application of a new low-field MR system in acute musculoskeletal imaging in radiology are presented. MATERIALS AND METHODS: This system is designed as a three-sided open permanent magnet with a revolving table. Main magnetic field strength is 0.2 T, maximal gradient field strength 20 mT/m, and minimal gradient rise time is 800 microseconds. First clinical experiences in 25 patients with acute trauma of peripheral joints were obtained. The following sequences were applied: gradient-echo (GRE) STIR, T1-weighted spin-echo, and PD- and T2-weighted turbo spin-echo. Correlation with the findings of high-field MR (1.5 T), plain radiograms (including stress views), CT or ultrasound was available in each patient confirming the low-field diagnoses. Furthermore, phantom measurements were performed to verify the spatial resolution of the system for some sequences with typical measurement parameters. DISCUSSION: This low-field system has several advantages: fast and economic installation, limited required space, easy operation, and high patient comfort. The medical benefit of such a system integrated in the traumatological suite of a radiological department seems to be evident due to the impact on the early initiation of the correct therapy which avoids additional diagnostic procedures and therefore may reduce costs. Implementation of such a system may be useful, if installation of an additional high-field scanner is not possible due to economic considerations.

Adolescent↗

PubMed2001

[Fully automated floating table MR angiography of pelvic and leg arteries: initial clinical results].

The aim of this study was to obtain first clinical experiences with magnetic resonance angiography (MRA) with digital subtraction (MR-DSA) using an automatic floating table for visualization peripheral arteriosclerotic occlusive disease (paod). We examined 10 patients on a 1.5 T MR unit applying a fast MRA technique (3D FLASH) with intravenous application of positive contrast agent. MR-DSA examinations were compared with the gold standard intraarterial (i.a.) DSA. MR-DSA proved to be useful for routine application which could be performed sufficiently in all patients. MR-DSA and i.a. DSA showed comparable results for imaging of the pelvic and upper leg arteries. Looking at the thighs image quality of MR-DSA did not match the image quality of i.a. DSA in every case. This was due to venous overlap and in comparison to i.a. DSA reduced signal-to-noise ratios. However, clinical findings, obtained with MR-DSA, were sufficient for adequate therapy planning. Our preliminary results reveal the potential of this new technique to become a realistic, robust, and non-invasive alternative to i.a. DSA in the diagnosis of paod.

Aged↗

PubMed2000

Endovascular brachytherapy for prophylaxis of restenosis after femoropopliteal angioplasty : results of a prospective randomized study.

BACKGROUND: Inasmuch as endovascular brachytherapy (BT) has gained recent interest because of its inhibitory effect on mechanisms leading to restenosis after percutaneous transluminal angioplasty (PTA), we performed this randomized study to determine its efficacy for prophylaxis of restenosis after femoropopliteal PTA. METHODS AND RESULTS: One hundred thirteen patients (63 men, 50 women; mean age 71 years) with de novo or recurrent femoropopliteal lesions were included in this randomized trial comparing the restenosis rate after PTA plus BT (57 patients, PTA+BT group) versus PTA (56 patients, PTA group) without stent implantation. The mean treated length was 16.7 cm (PTA+BT group) versus 14.8 cm (PTA group). In patients randomized to PTA plus BT, a dose of 12 Gy was applied by an (192)Ir source 3 mm from the source axis. Follow-up examinations included measurement of the ankle-brachial index, color-flow duplex sonography, and angiography. The primary end point of the study was patency after 6 months. The overall recurrence rate after 6 months was 15 (28.3%) of 53 in the PTA+BT group versus 29 (53.7%) of 54 in the PTA group (chi(2) test, P<0.05). The cumulative patency rates at 12 months of follow-up were 63.6% in the PTA+BT group and 35.3% in the PTA group (log-rank test, P<0.005). CONCLUSIONS: This is the first randomized study to demonstrate the efficacy of endovascular BT for prophylaxis of restenosis after femoropopliteal PTA. The value of this approach should now be improved by modification of the BT procedure and by combination with stent implantation.

Aged↗

PubMed2000

Intraarterial (192)Ir high-dose-rate brachytherapy for prophylaxis of restenosis after femoropopliteal percutaneous transluminal angioplasty: the prospective randomized Vienna-2-trial radiotherapy parameters and risk factors analysis.

PURPOSE: The aim of the Vienna-2-trial was to compare the restenosis rate of femoropopliteal arteries after percutaneous transluminal angioplasty (PTA) with or without intraarterial high-dose-rate (HDR) brachytherapy (BT) using an (192)Ir source. MATERIALS AND METHODS: A prospective, randomized trial was conducted from 11/96 to 8/98. A total of 113 patients (63 men, 50 women), with a mean age of 71 years (range, 43-89 years) were included. Inclusion criteria were (1) claudication or critical limb ischemia, (2) de-novo stenosis of 5 cm or more, (3) restenosis after former PTA of any length, and (4) no stent implantation. Patients were randomized after successful PTA for BT vs. no further treatment. A well-balanced patient distribution was achieved for the criteria used for stratification, as there were "de-novo stenosis vs. restenosis after former PTA," "stenosis vs. occlusion," "claudication vs. critical limb ischemia" and above these for "diabetes vs. nondiabetes." PTA length was not well balanced between the treatment arms: a PTA length of 4-10 cm was seen in 19 patients in the PTA alone group and in 11 patients in the PTA+BT group, whereas a PTA length of greater than 10 cm was seen in 35 patients and 42 patients, respectively. A dose of 12 Gy was prescribed in 3-mm distance from the source axis. According to AAPM recommendations, the dose was 6.8 Gy in 5-mm distance (vessel radius + 2 mm). Primary endpoint of the study was femoropopliteal patency after 6 months. RESULTS: PTA and additional BT were feasible and well tolerated by all 57 pts in this treatment arm. No acute, subacute, and late adverse side effects related to BT were seen after a mean follow up of 12 months (6-24 months) in 107 patients (PTA n = 54; PTA+ BT n = 53). Crude restenosis rate at 6 months was in the PTA arm 54% vs. 28% in the PTA + BT arm (chi(2) test; p < 0.013). Actuarial estimate of the patency rate was at 6 months 45% vs. 72% (p < 0.004). Comparison of restenosis rates for the different subgroups with risk factors (restenosis after former PTA, occlusion and PTA length >10 cm) showed significant decrease of the restenosis rate, if BT was added. Significant reduction was not achieved in diabetes patients. CONCLUSION: BT after femoropopliteal PTA is feasible and a safe therapeutic option. No BT related morbidity was observed. A significant reduction of the restenosis rate was obtained in the PTA+BT arm. Subgroup analysis showed significant decrease of restenosis rate in the subgroups with restenosis after former PTA, occlusion and PTA length of greater than 10 cm. With dose escalation and reduction of dose variation by a centering device a further significant decrease of restenosis rate can be expected.

Adult↗

PubMed2000

Dedicated phased-array coil for peripheral MRA.

In this paper we introduce a phased-array coil dedicated for MRA of peripheral arteries which covers the upper and lower legs. The structure of this coil includes a solid cabinet with four flexible wings forming a "T." The flexibility of the wings allows adaptation to the individual leg size. There are eight circularly polarized channels, four on each side. This coil is compatible with other surface coils. For MRA of peripheral arteries, it is combined with the body phased-array coil and the spine array coil which cover the lower abdomen and the pelvis. We examined six patients using this coil combination. The image quality, the signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of these examinations were compared with that of peripheral MRA examinations obtained with the body resonator. Image quality with the array coil was considerably improved in comparison with the body resonator examinations. The SNR and CNR increased approximately 100%. The handling of this coil was very quick and simple, similar to the procedure with other surface coils. The use of dedicated phased-array coils for peripheral MRA may be an important step toward the establishment of MR digital subtraction angiography (DSA) as a non-invasive alternative to intra-arterial DSA in the visualization of peripheral arteries. Its potential has to be evaluated in future studies.

Aged↗

PubMed2000

Fluoroscopically triggered contrast-enhanced 3D MR DSA and 3D time-of-flight turbo MRA of the carotid arteries: first clinical experiences in correlation with ultrasound, x-ray angiography, and endarterectomy findings.

The aim of this article was to obtain initial experiences with fluoroscopically triggered contrast-enhanced (CE) 3D MR DSA with elliptical centric k-space order and 3D time-of-flight (TOF) turbo MRA of the carotid arteries. In this prospective study we examined 16 consecutive patients with suspicion of atherosclerotic disease involving the carotid arteries. Ultrasound was available in all, x-ray angiography in 12, surgical correlation in 9, and intraoperative x-ray angiography in 4 patients. All examinations were done on a 1.5 T unit applying: transverse plain 3D TOF turbo MRA and coronal CE MRA with fluoroscopic triggering. Combining head and neck array coils allowed the visualization of supraaortic arteries from the aortic arch to the circle of Willis. MRA results (maximum intensity projections) were compared with x-ray angiography, ultrasound, and inspection of endarterectomy specimens. Volume rendering was performed in selected cases additionally. Agreement between CE MRA, 3D TOF turbo MRA and x-ray angiography regarding stenoses of the internal and external carotid artery was very good. CE MRA was able to detect correctly intracranial stenoses, but delineation of the aortic arch and proximal common carotid arteries was sometimes reduced. Volume rendering was suited for visualization of MRA images providing a realistic three-dimensional impression. In conclusion, high-resolution fluoroscopically triggered CE MRA as non-invasive technique is another important step on the way to replace invasive x-ray angiography for the evaluation of atherosclerotic carotid artery disease. High resolution 3D TOF turbo MRA might be a helpful adjunct to increase the diagnostic reliability for the carotid bifurcation.

Aged↗

PubMed2000

[A hybrid technique for the automatic floating table MRA of peripheral arteries using a dedicated phased-array coil combination].

PURPOSE: We introduce a hybrid technique which allows a high resolution MRA of the peripheral arteries with a dedicated phased-array coil using the floating table technique. MATERIALS AND METHODS: Five patients with peripheral arterial occlusive disease were examined within one week with i.a. DSA and MRA using the hybrid technique. MRA examinations were done on a 1.5 T system. At first, pelvic arteries were examined in a single step mode applying the CareBolus technique. Subsequently, thighs and lower legs were examined using the floating table mode. 125 vascular segments were evaluated. RESULTS: The hybrid technique proved to be robust and could be performed in each case. Mean examination time was about 30 min. For 117 vascular segments no difference was found between i.a. DSA and MRA. Three segments revealed a higher grade of stenosis in DSA than in MRA, five segments were graded higher in MRA than in DSA. Occlusions were visualized identically in both methods. Venous overlap had no relevant effects on image evaluation. CONCLUSIONS: This hybrid technique in combination with phased-array coils allows a high resolution MRA of the peripheral arteries with very good image quality. If future studies confirm reduced venous overlap, this method may be an alternative also for users of the floating table MRA with the body resonator.

Arterial Occlusive Diseases↗

PubMed1999

[A comparison of CT-supported 3D planning with simulator planning in the pelvic irradiation of primary cervical carcinoma].

BACKGROUND: Using standardized simulator planning guided by bony landmarks for pelvic irradiation of primary cervical carcinoma with some patients a geographical miss regarding tumor or potential tumor spread can happen because of insufficient knowledge of the individual anatomical situation. The question arises whether for patients with this indication the higher effort in terms of time and personnel for 3D treatment planning is justified. PATIENTS AND METHOD: In a prospective study on 20 subsequent patients with primary cervical carcinoma in Stages I to III simulator planning of a 4-field box-technique was performed. After defining the planning target volume (PTV) in the 3D planning system the field configuration of the simulator planning was transmitted. The resulting plan was compared to a second one based on the defined PTV and evaluated regarding a possible geographical miss and encompassment of the PTV by the treated volume (ICRU). Volumes of open and shaped portals were calculated for both techniques. RESULTS: Planning by simulation resulted in 1 geographical miss and in 10 more cases the encompassment of the PTV by the treated volume was inadequate. For a PTV of mean 1,729 cm3 the mean volume defined by simulation was 3,120 cm3 for the open portals and 2,702 cm3 for the shaped portals (Figure 1). The volume reduction by blocks was 13.4% (mean). With CT-based 3D treatment planning the volume of the open portals was 3.3% (mean) enlarged to 3,224 cm3 (Figure 2). The resulting mean volume of the shaped portals was 2,458 ccm. The reduction compared to the open portals was 23.8% (mean). The treated volumes were 244 cm3 or 9% (mean) smaller compared to simulator planning. The "treated volume/planning target volume ratio" was decreased from 1.59 to 1.42. CONCLUSION: The introduction of 3D treatment planning for pelvic irradiation of cervical carcinoma is to be recommended for reasons of quality assurance. Reduction of the treated volume is possible but further research has to be done to determine whether the rate of complications can be decreased as well.

Brachytherapy↗

PubMed1999

The benefit of Beam's eye view based 3D treatment planning for cervical cancer.

PURPOSE: The aim of this study was to evaluate the possibility of Beam's eye view (BEV) based three dimensional (3D) treatment planning, to reduce portions of organs at risk included in the treated volume without increasing the risk of geographical miss in external beam therapy of cervical cancer. MATERIALS AND METHODS: Three dimensional dose distribution of BEV based 3D treatment plans was compared to the 3D dose distribution derived from a four-field-box-technique using standard portals. A total of 20 patients with cervical cancer stage FIGO IIB and FIGO IIIB was included. Dose distribution in the target volumes and in the organs at risk of BEV based treatment planning, was compared to the dose distribution of the standard field technique using dose-volume-histograms. RESULTS: In 4/20 patients (20%) a geographical miss at the cervix uteri was observed for the standard field technique. The BEV based treatment planning resulted in an adequate coverage of target volume and additionally in a reduction of portions of bladder and bowel volume included in the treated volume (-13.5, -10%). In contrast the BEV based technique resulted in an increase of portions of the rectum volume included in the treated volume compared to standard portals due to a shift of the rectum by the enlarged cervix uteri from its posterior to a lateral position. An overall 7% reduction of treated volume was observed, although the maximum width of lateral fields increased for the BEV technique. Moreover, we have found a remarkable impact of bladder fillings on the amount of bowel and bladder volume included in the treated volume. CONCLUSION: BEV based 3D treatment planning for external beam therapy of cervical cancer offers a possibility to avoid geographical miss of part of the CTV with reduced portions of bladder and bowel volume included in the treated volume.

Female↗