Natascha Gerstner

The influence of a rectal balloon tube as internal immobilization device on variations of volumes and dose-volume histograms during treatment course of conformal radiotherapy for prostate cancer

PURPOSE A prospective comparative study of a subset of 10 consecutive patients was performed, to describe the effects of an air-inflated rectal balloon tube that has been used for prostate immobilization in 360 patients since 1994. In particular, influences on prostate motion, rectum filling variations, and dose-volume histograms (DVHs) of the rectum during a course of conformal radiotherapy were investigated. METHODS AND MATERIALS Computed tomographic (CT) examinations without and with rectal balloon (filled with 40 mL air) were performed at the start (t(0)), middle (t(mi)), and end of treatment (t(e)), resulting in 6 CT scans for each patient. Prostate displacement was measured from a lateral beams-eye-view. DVHs of rectum as a solid organ, and anterior, posterior, and whole rectum wall were calculated at t(0), t(mi), and t(e), and variations during treatment were analyzed for both examinations, with and without balloon. RESULTS By use of the balloon, rectum filling variations (p = 0.04) and maximum anterior-posterior displacements of the prostate (p = 0.008) were reduced significantly, leading to a reduction in DVH variations during treatment. Maximum displacements of posterior prostate border (>5 mm) were found in 8/10 patients without a rectum balloon and in only 2/10 patients with the balloon. The balloon led to a significant reduction in partial posterior rectal wall volumes included in the high-dose regions, without significant changes at the anterior rectum wall in cases of irradiation of the prostate only. However, when entirely irradiating the whole seminal vesicles, this advantage was lost. CONCLUSIONS The rectal balloon catheter represents a simple technique to immobilize the prostate and to determine the position of the anterior rectal wall at daily treatment. This allows a reduction of margins, because of reduced prostate movement during treatment course.

Rectal sequelae after conformal radiotherapy of prostate cancer: dose-volume histograms as predictive factors.

PURPOSE To identify clinically relevant parameters predictive of late rectal bleeding derived from cumulative dose-volume histograms (DVHs) of the rectum after conformal radiotherapy of prostate cancer. MATERIALS AND METHODS One hundred and nine patients treated with 3D conformal radiotherapy between 1/1994 and 1/1996 for localized prostate cancer (clinical stage T1-T3) were available for analysis. All patients received a total dose of 66 Gy/2 Gy per fraction (specified at the International Commission on Radiation Units and Measurements ICRU reference point). DVHs of the contoured rectum were analyzed by defining the absolute (aV) and relative (rV) rectum volume that received more than 30% (V30), 50% (V50), 70% (V70), 80% (V80), 90% (V90) and 100% (V100) of the prescribed dose. Additionally, a new aspect of DVH analysis was investigated by calculation of the area under the DVH-curve between several dose levels (area under the curve (AUC)-DVH). DVH-variables were correlated with radiation side effects evaluated in 3-6 months intervals and graded according to the EORTC/RTOG score. The median follow-up was 30 months (12-60 months). RESULTS Univariate and multivariate stepwise Cox-Regression analysis including age, PTV, rectum size, rV100, rV90, rV80, rV70, rV50 rV30 and aV30 to aV100 were calculated. Late rectal bleeding (EORTC/RTOG grade 2) was significantly correlated with the percentage of rectum volume receiving > or = 90% of the prescribed dose (rV90) (P = 0.007) and inversely correlated in a significant way with the size of contoured rectum (P = 0.006) in multivariate analysis. In our series, a proportion of the rectum volume > or = 57% were included in the 90%-isodose (rV90 > or = 57%) in one half of the patients, with an actuarial incidence of 31% of late rectal bleeding at 3 years. In the other half of the patients, when rV90 < 57%, the 3-year actuarial incidence was 11% (P < 0.03). CONCLUSION Our data demonstrate a dose-volume relationship at the reference dose of 60 Gy ( approximately 90% of the prescribed dose) with respect to late rectal toxicity. The rV90 seems to be the most useful and easily obtained parameter when comparing treatment plans to evaluate the risk of rectal morbidity.

Endoscopic scoring of late rectal mucosal damage after conformal radiotherapy for prostatic carcinoma

PURPOSE To describe rectal mucosal damage in an endoscopic study after conformal radiotherapy of prostate cancer and to correlate this with clinical outcome. MATERIALS AND METHODS Flexible rectosigmoidoscopy was performed on 44 patients who voluntarily accepted the examination. The median follow-up was 29 months (20-41 months) after 3-D-planned conformal radiotherapy of prostate cancer (66 Gy at the ICRU Reference point, 2 Gy per fraction). To enable a systematic topographic description of endoscopic findings the rectum was divided into four sections. Additionally we differentiated between anterior, posterior, right and left lateral rectal wall. Due to the lack of an existing valid graduation system for radiation induced proctitis, we introduced a six-scaled rectoscopy score for describing and reporting endoscopic findings based on the standardization of the endoscopic terminology published by the ESGE (European Society for Gastrointestinal Endoscopy). Endoscopic findings were compared to the EORTC/RTOG morbidity score. In addition, since 3-D dose distribution of organs at risks was available, a correlation could be made between the location of the rectal lesions and the absorbed dose at that level. RESULTS In general, endoscopic findings increased from the proximal rectum to the anorectal transition, as well as from the posterior to the anterior rectum wall. Telangiectasia grade 1 and 2 were observed at the whole circumference, only telangiectasia grade 3 were limited to the high dose region at the anterior rectum wall. Similar results were found for congested mucosa (reddening and edematous mucosa). Correlation with symptoms, 7/9 patients who suffered from intermittent rectal bleeding (EORTC/RTOG grade 2) had multiple telangiectasia grade 2-3 and/or congested mucosa grade 3 and microulcerations. However, the same extent of mucosal damage (rectoscopy score 2-3) was found in seven out of 35 patients who have never developed a period of macroscopic rectal bleeding. CONCLUSION Rectoscopy offers the possibility of detecting signs of tissue dysfunction below the level of subjective symptoms. Systematic analytic examinations such as rectoscopy, in addition to clinical examinations, as already foreseen in the LENT-SOMA-score, will be necessary due to the fact that even telangiectatic lesions have been observed for asymptomatic patients. For the opportunity of sharing and comparing data collected from endoscopy after radiotherapy a graduation system as proposed based on a standardisation of the endoscopic terminology will be necessary.

Die bedeutung eines rektumballons als interne immobilisation bei der konformalen strahlentherapie des prostatakarzinoms

BACKGROUND As known from the literature, prostate motion depends on different bladder and/or rectum fillings. The aim of this study was to analyze the influence of a rectum balloon catheter, used as an internal immobilization device, on prostate and rectum motion during the treatment course. Moreover we have analyzed if the balloon enables an increase of the distance between the prostate and the posterior rectum wall. PATIENTS AND METHODS Ten patients with localized prostate cancer (T1 to T3) underwent computed tomographic examinations with and without rectal balloon (filled with 40 ml air) at 3 times during treatment course (at the start, middle and end of treatment). Edges of prostate, rectum and bladder were measured in relation to bony reference structures and compared for both examination series (with and without balloon). RESULTS An increase of the distance between the prostate and the posterior rectal wall of 8 mm was observed at the base of the prostate when using the rectum balloon (Figures 1a,b and 2). Moreover prostate motion in the ventrodorsal direction > or = 4 mm (1 SD) was reduced from 6/10 patients (60%) to 1/10 patients (10%) using the rectal balloon (Table 3, Figure 3). In general, deviations in the latero-lateral and cranio-caudal directions were less (mean < or = 2 mm, 1 SD), no difference between both examination series (with and without balloon) was observed. CONCLUSION Rectal balloon catheter offers a possibility to reduce prostate motion and rectum filling variations during treatment course. In addition it enables an increase in the distance between prostate and posterior rectal wall, which could enable an improved protection of the posterior rectal wall.HintergrundDie Lageveränderung der Prostata, bedingt durch unterschiedliche Harnblasen- und Rektumfüllungen, wurde bereits in einigen Studien untersucht. Ziel dieser Studie war es, zu prüfen, ob durch die Anwendung eines Rektumballonkatheters als interne Immobilisation der Prostata eine Reduktion der Prostataeigenbeweglichkeit möglich ist. Darüber hinaus wurde untersucht, inwieweit durch den Rektumballon der Abstand zwischen Prostata und Rektumhinterwand vergrößert werden kann.Patienten und MethodeDrei konsekutive Planungscomputertomographien (Therapiebeginn, Therapiemitte, Therapieende) von zehn Patienten mit lokal begrenztem Prostatakarzinom (Tl bis T3) wurden jeweils mit und ohne Rektumballon (gefüllt mit 40 ml Luft) angefertigt. Die Lage von Prostata und Rektum im Therapieverlauf beider Untersuchungsserien (mit und ohne Rektumballon) wurde in Relation zu knöchernen Referenzstrukturen vermessen und miteinander verglichen.ErgebnisseDurch die Anwendung des Rektumballons konnte der Abstand zwischen Prostata und Rektumhinterwand an der Prostatabasis im Mittel um 8 mm vergrößert werden. Insgesamt konnte durch den Rektumballon die Prostatabewegung in ventrodorsaler Richtung deutlich reduziert werden. Die Anzahl jener Patienten, bei denen eine ventrodorsale Bewegung der zentralen Prostata im Therapieverlauf ≥ 4 mm (1 SD) beobachtet wurde, konnte durch die Anwendung des Rektumballons von 6/10 Patienten (60%) auf 1/10 Patienten (10%) reduziert werden. Die Lageveränderungen der Prostata in laterolateraler und kraniokaudaler Richtung waren deutlich geringer als jene in ventrodorsaler Richtung (im Mittel ≤ 2 mm, 1 SD) und wurden durch den Rektumballon nicht beeinflußt.SchlußfolgerungDie Anwendung des Rektumballons ermöglicht eine Reduktion der Prostataeigenbeweglichkeit in ventrodorsaler Richtung im Sinne einer internen Immobilisation. Zusätzlich wird eine Vergrößerung des Abstands zwischen Prostata und Rektumhinterwand erreicht, wodurch eine bessere Schonung der Rektumhinterwand möglich scheint.AbstractBackgroundAs known from the literature, prostate motion depends on different bladder and/or rectum fillings. The aim of this study was to analyze the influence of a rectum balloon catheter, used as an internal immobilization device, on prostate and rectum motion during the treatment course. Moreover we have analyzed if the balloon enables an increase of the distance between the prostate and the posterior rectum wall.Patients and MethodsTen patients with localized prostate cancer (Tl to T3) underwent computed tomographic examinations with and without rectal balloon (filled with 40 ml air) at 3 times during treatment course (at the start, middle and end of treatment). Edges of prostate, rectum and bladder were measured in relation to bony reference structures and compared for both examination series (with and without balloon).ResultsAn increase of the distance between the prostate and the posterior rectal wall of 8 mm was observed at the base of the prostate when using the rectum balloon (Figures la,b and 2). Moreover prostate motion in the ventrodorsal direction ≥ 4 mm (1 SD) was reduced from 6/10 patients (60%) to 1/10 patients (10%) using the rectal balloon (Table 3, Figure 3). In general, deviations in the latero-lateral and cranio-caudal directions were less (mean ≤ 2 mm, 1 SD), no difference between both examination series (with and without balloon) was observed.ConclusionRectal balloon catheter offers a possibility to reduce prostate motion and rectum filling variations during treatment course. In addition it enables an increase in the distance between prostate and posterior rectal wall, which could enable an improved protection of the posterior rectal wall.

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 Beams 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.

[Planned 3-dimensional low-volume conformal irradiation of a local prostatic carcinoma].

AIM Recent data have shown a significant reduction of acute side effects by means of a three-dimensional planned conformal radiotherapy of carcinoma of the prostate compared to treatment techniques used before. Theoretically, an optimized field coverage of the planning target volume should result in a reduction of treated bladder and rectum volumes. We studied the effects of individualized blocks on treatment volumes, planning target volumes, irradiated bladder and rectum volumes on basis of three-dimensional treatment planning by means of beams-eye-view technique. PATIENTS AND METHOD We compared dose-volume-histograms of 2 different planning models, a (fictitious) open 4-field-box-technique and a technique with conformal blocked fields designed from the beams-eye-view display (prescribed dose 66 Gy, daily single fraction 2 Gy). Plans of 115 patients with localized prostate cancer treated from January 1994 to February 1996 were analyzed. RESULTS Using individualized fields treatment volume (covered by the 90%-isodose) was reduced by 23% on the average in comparison to the planning model without blocks. The averaged difference of treated volume and planning target volume, as a grade of efficiency of conformation, was reduced by 38% (496 cm3 303 cm3) using individualized blocks. 23% of the treated bladder volume and 13% of the treated rectum volume had been saved on the average. Nevertheless, at least 11.5% of the bladder volume and 27.6% of the contoured rectum volume were treated with the prescribed dose (55 Gy = 100%). CONCLUSIONS The comparison of dose-volume-histogram-data showed that especially high dose volumes of organs at risk had been saved by means of individualized blocks created from the beams-eye-view. The blocks did not affect the dose distribution of the planning target volume adversely. Consequently the impact of these data on the extent of side effects and local tumor control has to be proven.ZusammenfassungZielNeuere Arbeiten zeigen eine signifikante Reduktion akuter Nebenwirkungen durch 3D-geplante Konformationstherapie des Prostatakarzinoms im Vergleich zu herkömmlichen Bestrahlungstechniken. Die theoretische Grundlage dafür ist eine optimale Feldanpassung an das Zielvolumen mit daraus resultierender Reduktion von Harnblasen- und Rektumvolumina im Bestrahlungsfeld. Wir untersuchten, welche Veränderungen sich an Behandlungsvoluminia, Planungszielvolumina, exponierten Harnblasen- und Rektumvolumina durch Anwendung 3D-geplanter Konformationsbestrahlung der Prostata mit Individualblöcken ergeben.Patienten und MethodeDosis-Volumen-Histogramm-Daten einer (fiktiven) Vier-Felder-Box-Planvariante ohne Blöcke wurden mit denen einer tatsächlich angewandten Vier-Felder-Box-Planvariante (verordnete Dosis 66 Gy, 2 Gy tägliche Einzeldosis) mit Individualabsorbern verglichen. Die Feldformung erfolgte mit Hilfe der Beam’s-eye-view-Technik. Die Pläne von 115 Patienten mit lokalisiertem Prostatakarzinom des Behandlungszeitraumes Januar 1994 bis Februar 1996 wurden ausgewertet.ErgebnisseDurch die Verwendung von Individualböblocken wurde das Behandlungsvolumen (innerhalb der 90%-Isodose) im Vergleich zur Planvariante ohne Blöcke im Mittel um 23% verkleinert. Die Differenz vom Behandlungsvolumen und Planungszielvolumen, als Maß für die Effektivität der Konformation, wurde durch den Einsatz der Individualblöcke um 38% (496 cm3 vs. 306 cm3) reduziert. Es konnten durchschnittlich 23% des behandelten Harnblasenvolumens und 13% des behandelten Rektumvolumens durch die Verwendung von Individualblöcken eingespart werden. Dennoch wurden bei der tatsächlich verwendeten Planvariante 11,5% des gesamten Harnblasenvolumens und 27,6% des konturierten Rektumvolumens mit der verordneten Dosis (66 Gy=100%) bestrahlt.SchlußfolgerungenDer Vergleich der Dosis-Volumen-Histogramme zeigte, daß mit Hilfe der BEV-Technik Risikoorgane vor allem im klinisch relevanten Hochdosisbereich gezielt geschont werden konnten, ohne dabei die Dosisverteilung im Planungszielvolumen nachteilig zu beeinflussen. Als nächstes ist die klinische Bedeutung dieser Daten bezüglich radiogener Nebenwirkungen und lokaler Tumorkontrolle zu überprüfen.AbstractAimRecent data have shown a significant reduction of acute side effects by means of a threedimensional planned conformal radiotherapy of carcinoma of the prostate compared to treatment techniques used before. Theoretically, an optimized field coverage of the planning target volume should result in a reduction of treated bladder and rectum volumes. We studied the effects of individualized blocks on treatment volumes, planning target volumes, irradiated bladder and rectum volumes on basis of threedimensional treatment planning by means of beam’s-eye-view technique.Patients and MethodWe compared dose-volume-histograms of 2 different planning models, a (fictitious) open 4-field-box-technique and a technique with conformal blocked fields designed from the beam’s-eye view display (prescribed dose 66 Gy, daily single fraction 2 Gy). Plans of 115 patients with localized prostate cancer treated from January 1994 to February 1996 were analyzed.ResultsUsing individualized fields treatment volume (covered by the 90%-isodose) was reduced by 23% on the average in comparison to the planning model without blocks. The averaged difference of treated volume and planning target volume, as a grade of efficiency of conformation, was reduced by 38% (496 cm3 vs. 303 cm3) using individualized blocks. 23% of the treated bladder volume and 13% of the treated rectum volume had been saved on the average. Nevertheless at least 11.5% of the bladder volume and 27.6% of the contoured rectum volume were treated with the prescribed dose (66 Gy=100%).ConclusionsThe comparison of dose-volume-histogram-data showed that especially high dose volumes of organs at risk had been saved by means of individualized blocks created from the beam’s-eye-view. The blocks did not affect the dose distribution of the planning target volume adversely. Consequently the impact of these data on the extent of side effects and local tumor control has to be proven.

Three dimensional conformal photon radiotherapy at a moderate dose level of 66 Gy for prostate carcinoma: early results.

BackgroundThe therapeutic outcome and toxicity of 3-D conformal photon external beam therapy of prostate cancer is well documented in the literature. Progress is still in work for optimization of treatment strategies by risk-adapted dose escalation studies to improve local tumor control without increase of radiation side effects.Patients and MethodsWe present our experience of 291 patients treated between January 1994 and August 1997 with a 3-D planned four-field box technique and a central dose of 66 Gy. Biochemical response of patients with radiotherapy alone (group 1, n=72 pts.) has been analyzed in detail. Acute radiation side effects are given for all patients (n=291), late radiation side effects are given for patients treated between Jan 1994 and Jan 1996 with a median follow-up of 22 months (n=115 pts.).ResultsWe have observed a biochemical response (nadir PSA<1 after 12 months, <2 after 6 months) for patients treated with radiotherapy alone without hormone manipulation in 67%. Incidence of late rectal and bladder morbidity (grade 2 and 3) was 9.4% and 4%, respectively.ConclusionCompared to other reports our results indicate a high rate of local tumor control (early biochemical response) and a low rate of late morbidity. Nevertheless, we will start a risk-adapted dose escalation study up to 74 Gy for unfavorable subgroups (G2-3, Gleason Score>7, PSA>10) to improve treatment outcome.

Dreidimensional geplante kleinvolumige Konformationsbestrahlung des lokalen Prostatakarzinoms

Ziel Neuere Arbeiten zeigen eine signifikante Reduktion akuter Nebenwirkungen durch 3D-geplante Konformationstherapie des Prostatakarzinoms im Vergleich zu herkommlichen Bestrahlungstechniken. Die theoretische Grundlage dafur ist eine optimale Feldanpassung an das Zielvolumen mit daraus resultierender Reduktion von Harnblasen- und Rektumvolumina im Bestrahlungsfeld. Wir untersuchten, welche Veranderungen sich an Behandlungsvoluminia, Planungszielvolumina, exponierten Harnblasen- und Rektumvolumina durch Anwendung 3D-geplanter Konformationsbestrahlung der Prostata mit Individualblocken ergeben.

Monitorbeurteilung digitalisierter und nachbearbeiteter Feldkontrollaufnahmen im Vergleich zu konventionellen Feldkontrollaufnahmen am Röntgenschaukasten

ZusammenfassungZielBeurteilung der Bildqualität und Detailerkennbarkeit digitalisierter und nachbearbeiteter Feldkontrollaufnahmen am Computermonitor im Vergleich zum bisherigen Standard, der Beurteilung konventioneller Feldkontrollaufnahmen am Röntgenschaukasten.Material und MethodeKonventionelle Feldkontrollaufnahmen von drei unterschiedlichen Tumorregionen (zehn Becken-, zehn Schädel- und zehn Wirbelsäulenaufnahmen) wurden acht Untersuchern in drei verschiedenen Varianten präsentiert: konventioneller Film am Röntgenschaukasten (Konv), digitalisierte Feldkontrollaufnahme ohne Nachbearbeitung (Dig-1), digitalisierte Feldkontrollaufnahme mit einfacher Bildnachbearbeitung (Dig-2) am Computermonitor. Die subjektive Bewertung der Bildqualität, die Detailerkennbarkeit und der Zeitaufwand für die Beurteilung am Röntgenschaukasten im Vergleich zur Monitorbeurteilung wurden durch einen gezielten Fragebogen ermittelt. Die Untersucher konnten aus den vorgegebenen Antwortmöglichkeiten 1=viel besser bis 5=viel schlechter wählen. Zusätzlich mußten die Untersucher klar definierte knöcherne Referenzpunkte sowohl am konventionellen Film am Röntgenschaukasten als auch am digitalisierten, nachbearbeiteten Bild (Dig-2) am Computermonitor einzeichnen. Als objektives Maß für die Detailerkennbarkeit anatomischer Strukturen wurde die Streuung der von den unterschiedlichen Untersuchern eingezeichneten Punkte berechnet.ErgebnisseDie Bildqualität der digital nachbearbeiteten Bilder am Monitor wurde statistisch signifikant besser als jene der konventionellen Filme am Röntgenschaukasten beurteilt (Becken 78%, Wirbelsäule 62%, Schädel 45% besser). Ebenso wurde die Detailerkennbarkeit der digital nachbearbeiteten Bilder im Vergleich zu den konventionellen Filmen beurteilt (Becken 81%, Wirbelsäule 57%, Schädel 40% besser). Die größte Verbesserung der Bildqualität und detailerkennbarkeit bei der Beurteilung am Monitor konnte für das Becken ermittelt werden, jener Region mit erfahrungsgemäß schlecht beurteilbaren Feldkontrollaufnahmen. Im Gegensatz dazu wurde die Bildqualität von digital nicht nachbearbeiteten Bildern im Vergleich zu konventionellen Filmen schlechter beurteilt (Becken 69%, Wirbelsäule 53%, Schädel 71% schlechter). Der Zeitaufwand für die Beurteilung digital nachbearbeiteter Bilder am Computermonitor wurde vor allem für das Becken kürzer eingeschätzt als am Röntgenschaukasten (Becken 68%, Wirbelsäule 26%, Schädel 8% kürzer). Als objektivierbares Maß für die verbesserte Bildqualität und Detailerkennbarkeit zeigte sich für das Becken eine signifikant kleinere Standardabweichung der eingezeichneten Referenzstrukturen bei Dig-2-Aufnahmen im Vergleich zum konventionellen Film. Für die Wirbelsäule und den Schädel fanden sich keine signifikanten Unterschiede.Schlußfolgerung enDie Präsentation von digitalisierten und nachbearbeiteten Feldkontrollaufnahmen am Computermonitor führte trotz primär schlechter Bildqualität digitalisierter Aufnahmen durch entsprechende Bildnachbearbeitung zu einer rascheren Beurteilung und gleichwertigen bis besseren Bildqualität sowie Detailerkennbarkeit im Vergleich zur Beurteilung konventioneller Filme am Röntgenschaukasten.AbstractPurposeJudgement of image quality and detail recognition of digitized and post-processed portal films presented on a computer monitor compared to the present standard, conventional portal films presented on a light-box.Material and MethodsConventional portal films of 3 different tumor sites (10 pelvis, 10 cranium, 10 vertebral column) were presented to a panel of 8 observers in 3 different manners: conventional film presented on a light-box (Conv), digitized non-post-processed images (Dig-1) and digitized post-processed images (Dig-2) presented on a high-resolution computer monitor. Subjective judgement of image quality, detail recognition and time requirement of conventional films compared to monitor presentation were evaluated using a 5-scaled questionnaire (from 1=much better to 5=much worse). Furthermore the observers had to point out predefined anatomical bony structures on the conventional films (Conv) as well as on the digitized post-processed images (Dig-2). Standard deviations of the landmarks outlined by 10 different observers were used as a criterion of objective detail recognition (Figure 1).ResultsImage quality of digitized post-processed images presented on the computer monitor was judged statistical significant better than of conventional films (pelvis 78%, vertebral column 62%, cranium 45% better) (Figure 3). Similar results were found for comparison of detail recognition: digitized post-processed images were scored better for pelvis in 81%, for vertebral column in 57%, for cranium in 40% (Figure 4, Table 1). Most benefit from portal film enhancement was found for pelvic images, where portal films are known to be of poor image quality (Figure 2). In contrast image quality of non-processed digital images compared to conventional films was graded worse (pelvis 69%, vertebral column 53%, cranium 71% worse) (Figure 4). Digital post-processed images were especially for the pelvis judged to require less time (pelvis 68%, vertebral column 26%, cranium 8% less time requirement) (Figure 5). For the pelvis a statistical significant decrease of standard deviations was found for Dig-2 compared to conventional films, indicating an objective increase of image quality and detail recognition (Table 2). In case of vertebral column and cranium no significant differences were evaluated (Table 3).ConclusionsDigitized enhanced portal films presented on a computer monitor resulted in a quicker assessment and equal to better image quality as well as detail recognition compared to conventional films. Non-processed digitized images were judged to be of less image quality.

Ein verteiltes Bilddatenbank- und Bildverarbeitungssystem für medizinische Bilder

Internetbasierte Anwendungen eroffnen weitreichende Moglichkeiten der Kommunikation und des Datenaustausches. Wir stellen in diesem Zusammenhang ein in Entwicklung befindliches verteiltes Bilddatenbank- und Bildverarbeitungssystem fur medizinische Bilder vor. Die Benutzerschnittstelle und Kommunikation mit Servern wird in Java-Technologie realisiert. Das System verwaltet medizinische Bilder verschiedener Formate (DICOM [1], JPEG, GIF,...), und erlaubt dem Benutzer, Bildverarbeitungsoperationen auf die in der Datenbank oder lokal abgelegten Bilder anzuwenden. Hierbei werden einfache Bildmanipulationen wie Drehen, Spiegeln, Kontrast- und Helligkeitsveranderungen und Markierungsfunktionen bis zu Segmentationsverfahren wie Watershedding und der Visualisierung von dreidimensionalen Volumendaten [2] unterstutzt. Die Datenbank wird in der Lage sein, einfache Abfragen bezuglich Patienten, Organen, Krankheitssymptomen u.a. zu beantworten.