Christos Moustakis

Definition of stereotactic body radiotherapy

This report from the Stereotactic Radiotherapy Working Group of the German Society of Radiation Oncology (Deutschen Gesellschaft für Radioonkologie, DEGRO) provides a definition of stereotactic body radiotherapy (SBRT) that agrees with that of other international societies. SBRT is defined as a method of external beam radiotherapy (EBRT) that accurately delivers a high irradiation dose to an extracranial target in one or few treatment fractions. Detailed recommendations concerning the principles and practice of SBRT for early stage non-small cell lung cancer (NSCLC) are given. These cover the entire treatment process; from patient selection, staging, treatment planning and delivery to follow-up. SBRT was identified as the method of choice when compared to best supportive care (BSC), conventionally fractionated radiotherapy and radiofrequency ablation. Based on current evidence, SBRT appears to be on a par with sublobar resection and is an effective treatment option in operable patients who refuse lobectomy.ZusammenfassungDie Arbeitsgruppe „Stereotaktische Radiotherapie“ der Deutschen Gesellschaft für Radioonkologie (DEGRO) erarbeitete eine Definition der Körperstereotaxie (SBRT), die sich an vorhandene internationale Definitionen anlehnt: Die SBRT ist eine Form der perkutanen Strahlentherapie, die mit hoher Präzision eine hohe Bestrahlungsdosis in einer oder wenigen Bestrahlungsfraktionen in einem extrakraniellen Zielvolumen appliziert. Zur Praxis der SBRT beim nichtkleinzelligen Bronchialkarzinom (NSCLC) im frühen Stadium werden detaillierte Empfehlungen gegeben, die den gesamten Ablauf der Behandlung von der Indikationsstellung, Staging, Behandlungsplanung und Applikation sowie Nachsorge umfassen. Die Körperstereotaxie wurde als Methode der Wahl im Vergleich zu Best Supportive Care, zur konventionell fraktionierten Strahlentherapie sowie zur Radiofrequenzablation identifiziert. Die Ergebnisse nach SBRT und sublobärer Resektion erscheinen auf aktueller Datenbasis ebenbürtig. Die SBRT ist die Methode der Wahl, wenn Patienten einen operativen Eingriff in Form der Lappenresektion ablehnen.

Definition of stereotactic body radiotherapy: principles and practice for the treatment of stage I non-small cell lung cancer.

This report from the Stereotactic Radiotherapy Working Group of the German Society of Radiation Oncology (Deutschen Gesellschaft für Radioonkologie, DEGRO) provides a definition of stereotactic body radiotherapy (SBRT) that agrees with that of other international societies. SBRT is defined as a method of external beam radiotherapy (EBRT) that accurately delivers a high irradiation dose to an extracranial target in one or few treatment fractions. Detailed recommendations concerning the principles and practice of SBRT for early stage non-small cell lung cancer (NSCLC) are given. These cover the entire treatment process; from patient selection, staging, treatment planning and delivery to follow-up. SBRT was identified as the method of choice when compared to best supportive care (BSC), conventionally fractionated radiotherapy and radiofrequency ablation. Based on current evidence, SBRT appears to be on a par with sublobar resection and is an effective treatment option in operable patients who refuse lobectomy.ZusammenfassungDie Arbeitsgruppe „Stereotaktische Radiotherapie“ der Deutschen Gesellschaft für Radioonkologie (DEGRO) erarbeitete eine Definition der Körperstereotaxie (SBRT), die sich an vorhandene internationale Definitionen anlehnt: Die SBRT ist eine Form der perkutanen Strahlentherapie, die mit hoher Präzision eine hohe Bestrahlungsdosis in einer oder wenigen Bestrahlungsfraktionen in einem extrakraniellen Zielvolumen appliziert. Zur Praxis der SBRT beim nichtkleinzelligen Bronchialkarzinom (NSCLC) im frühen Stadium werden detaillierte Empfehlungen gegeben, die den gesamten Ablauf der Behandlung von der Indikationsstellung, Staging, Behandlungsplanung und Applikation sowie Nachsorge umfassen. Die Körperstereotaxie wurde als Methode der Wahl im Vergleich zu Best Supportive Care, zur konventionell fraktionierten Strahlentherapie sowie zur Radiofrequenzablation identifiziert. Die Ergebnisse nach SBRT und sublobärer Resektion erscheinen auf aktueller Datenbasis ebenbürtig. Die SBRT ist die Methode der Wahl, wenn Patienten einen operativen Eingriff in Form der Lappenresektion ablehnen.

Organ movements and dose exposures in teletherapy of prostate cancer using a rectal balloon.

Background and Purpose:During radiotherapy of localized prostate cancer, organ movements for the dose exposure of organs at risk like rectum, urinary bladder and urethra play, inter alia, a significant role. One possibility of internal organ stabilizing is offered by the usage of a rectal balloon during radiotherapy. The influence on organ movements and dose allocation of the organs at risk is unknown.Patients and Methods:Twelve patients (Table 1) were characterized based on planning-CTs regarding organ movements and organ doses using a rectal balloon, inflated with 0 ml and 60 ml air. For the determination of the organ doses, three-dimensional conformal radiation plans (3-field-pelvis box) with a cumulative dose of 59.4 Gy were created, and the dose-volume-histograms for the anterior rectal wall, the posterior rectal wall, the rectal mucosa, the whole rectum, as well as the urinary bladder were compared (Figures 1 and 2).Results:The application of a 60 ml air-filled rectal balloon during each fraction of teletherapy led to significant organ movements of the anterior and posterior rectal wall and to a reduction of the transversal prostate diameter, as well as to a changed organ dose exposure of the organs at risk. A ventral shift of the anterior rectal wall (maximum 0.8 cm, mean 0.4 cm) was shown, as well as a dorsal shift of the posterior rectal wall (maximum 1.2 cm, mean 0.7 cm), associated with a transversal prostate diameter decrease (maximum 0.8 cm, mean 0.3 cm) (Table 2, Figure 3). The organ dose of the anterior rectal wall increased significantly (maximum 1.3 Gy, mean 0.5 Gy) during application of a rectal balloon, the one of the posterior rectal wall decreased significantly (maximum 18.6 Gy, mean 6.5 Gy). Related to the entire rectal mucosa and the rectum as a complete organ, a decrease of the maximum doses was shown (rectal mucosa: maximum 9.1 Gy, mean 3.0 Gy; rectum: maximum 9.4 Gy, mean 3.7 Gy). The organ dose of the urinary bladder did not show significant changes (Tables 3 and 4, Figures 4 to 7).Conclusion:The application of a rectal balloon in teletherapy of localized prostate cancer leads to significantly changed dose exposition of organs at risk. The decreased dose exposure of the posterior rectal wall and the rectal mucosa is opposed by the higher organ dose of the anterior rectal wall. It has to be shown weather documented organ dose exposure is associated with short and long-term consequences.Hintergrund und Ziel:Bei der Strahlentherapie des lokalisierten Prostatakarzinoms spielen unter anderem die Organbewegungen für die Dosisexposition der Risikoorgane Rektum, Harnblase und Harnröhre eine entscheidende Rolle. Eine Möglichkeit der internen Organstabilisierung stellt die Verwendung eines Rektumballons bei der Strahlentherapie dar. Der Einfluss auf die Organbewegungen und die Dosisverteilung an den jeweiligen Risikoorganen ist unklar.Patienten und Methodik:12 Patienten (Tabelle 1) wurden auf der Grundlage von Planungs-Computertomogrammen hinsichtlich Organbewegungen und Organdosen unter Verwendung eines Rektumballons mit 0 ml und 60 ml Luftfüllung charakterisiert. Für die Bestimmung der Organdosen wurden dreidimensionale konformale Bestrahlungspläne (3-Felder-Beckenbox) mit einer Gesamtdosis von 59,4 Gy erstellt und die Dosis-Volumen-Histogramme für die Rektumvorderwand, die Rektumhinterwand, die Rektumschleimhaut, das gesamte Rektum sowie die Harnblase verglichen (Abbildungen 1 und 2).Ergebnisse:Die Verwendung eines mit 60 ml Luft gefüllten Rektumballons bei der Teletherapie führte zu signifikanten Organbewegungen im Bereich der Rektumvorderwand, Rektumhinterwand und zu einer Reduzierung des transversalen Prostatadurchmessers sowie zu veränderten Organdosen der Risikoorgane. Es zeigte sich eine Ventralverschiebung der Rektumvorderwand (Maximum 0,8 cm, Mittel 0,4 cm) sowie eine Dorsalverschiebung der Rektumhinterwand (Maximum 1,2 cm, Mittel 0,7 cm), verbunden mit einer Reduktion des transversalen Prostatadurchmessers (Maximum 0,8 cm, Mittel 0,3 cm) (Tabelle 2, Abbildung 3). Die Organdosis der Rektumvorderwand nahm unter Verwendung eines Rektumballons signifikant zu (Maximum 1,3 Gy, Mittel 0,5 Gy), die der Rektumhinterwand signifikant ab (Maximum 18,6 Gy, Mittel 6,5 Gy). Bezogen auf die gesamte Rektumschleimhaut und das Rektum als Gesamtorgan zeigte sich eine Reduktion der Maximaldosen (Rektumschleimhaut: max. 9,1 Gy, Mittel 3,0 Gy, Rektum: maximal 9,4 Gy, Mittel 3,7 Gy). Die Organdosis der Harnblase zeigte keine signifikante Veränderung (Tabellen 3 und 4, Abbildungen 4–7).Schlussfolgerung:Die Verwendung eines Rektumballons bei der Teletherapie des lokalisierten Prostatakarzinoms führt zu signifikant veränderter Dosisexposition von Risikoorganen. Geringeren Organdosen an Rektumhinterwand und Rektumschleimhaut steht eine höhere Organdosis der Rektumvorderwand entgegen. Inwieweit die unterschiedlichen Organdosen einen Einfluss auf Akut- und Spätfolgen haben, muss Gegenstand weiterer Untersuchungen sein.

Total Skin Electron Beam for Primary Cutaneous T-cell Lymphoma.

PURPOSE Recent trials with low-dose total skin electron beam (TSEB) therapy demonstrated encouraging results for treating primary cutaneous T-cell lymphoma (PCTCL). In this study, we assessed the feasibility of different radiation doses and estimated survival rates of different pathologic entities and stages. METHODS AND MATERIALS We retrospectively identified 45 patients with PCTCL undergoing TSEB therapy between 2000 and 2015. Clinical characteristics, treatment outcomes, and toxicity were assessed. RESULTS A total of 49 courses of TSEB therapy were administered to the 45 patients. There were 26 pathologically confirmed cases of mycosis fungoides (MF) lymphoma, 10 cases of Sézary syndrome (SS), and 9 non-MF/SS PCTCL patients. In the MF patients, the overall response rate (ORR) was 92% (50% complete remission [CR]), 70% ORR in SS patients (50% CR), and 89% ORR in non-MF/SS patients (78% CR). The ORR for MF/SS patients treated with conventional dose (30-36 Gy) regimens was 92% (63% CR) and 75% (25% CR) for low-dose (<30-Gy) regimens (P=.09). In MF patients, the overall survival (OS) was 77 months with conventional dose regimens versus 14 months with low-dose regimens (P=.553). In SS patients, the median OS was 48 versus 16 months (P=.219), respectively. Median event-free survival (EFS) for MF in conventional dose patients versus low-dose patients was 15 versus 8 months, respectively (P=.264) and 19 versus 3 months for SS patients (P=.457). Low-dose regimens had shorter treatment time (P=.009) and lower grade 2 adverse events (P=.043). A second TSEB course was administered in 4 MF patients with 100% ORR. There is a possible prognostic impact of supplemental/boost radiation (P<.001); adjuvant treatment (P<.001) and radiation tolerability (P=.021) were detected. CONCLUSIONS TSEB therapy is an efficacious treatment modality in the treatment of several forms of cutaneous T-cell lymphoma. There is a nonsignificant trend to higher and longer clinical benefit for MF and SS patients receiving conventional dose. Low-dose TSEB regimens are well tolerated and achieve short-term palliation.

12 years' experience with intraoperative radiotherapy (IORT) of malignant gliomas

Background:Even after surgery and radiotherapy, malignant gliomas still have a poor prognosis. The authors report on their experience with IORT in 71 patients.Patients and Methods:From May 1992 to February 2004, 71 patients with malignant gliomas were treated with IORT. 26 patients suffered from grade III gliomas, 45 patients from glioblastomas (GBM). IORT was carried out using a standard electron tube and 9- to 18-MeV electrons. 52/71 patients who were primarily treated received 20 Gy IORT + 60 Gy postoperative radiotherapy, 19/71 patients with recurrences only received IORT (20–25 Gy).Results:The complication rates were 1.4% for wound infections and 5.6% for hemorrhage. Median disease-specific survival amounted to 14.9 months (gliomas III) and 14.2 months (GBM). The 2-year survival rates amounted to 26.9% (gliomas III) and 6.8% (GBM; p = 0.0296). Total versus subtotal resection had no significant influence on survival (p = 0.0741), nor had age, sex, tumor site, performance status, size, primary versus recurrence, and radiation dose. A comparison to a conventionally treated patient group did not show a significant survival improvement. 3 months after treatment, initial symptoms had improved in 59% (hemiparesis), 50% (aphasia), 50% (hemianopsia), and 60% (convulsions).Conclusion:IORT has been shown to be feasible; perioperative complication rates were not increased. Survival was generally not improved compared to a historical control group. Recurrences achieved the same survival as primary tumors, and GBM also had a slightly increased survival, thus being possible indications for IORT.Hintergrund:Auch nach Resektion und Strahlentherapie haben maligne Gliome nach wie vor eine schlechte Prognose. Die Autoren berichten über ihre Erfahrungen mit der IORT bei 71 Patienten.Patienten und Methodik:Von Mai 1992 bis Februar 2004 wurden 71 Patienten mit malignen Gliomen mit IORT behandelt. 26 Patienten hatten Grad-III-Gliome, 45 Patienten Glioblastome (GBM). Die IORT wurde mittels eines üblichen Elektronentubus und 9- bis 18-MeV-Elektronen durchgeführt. 52/71 Patienten wurden primär mit 20 Gy IORT + 60 Gy postoperativer Radiotherapie behandelt, 19/71 Patienten mit Rezidiven erhielten nur eine IORT (20–25 Gy).Ergebnisse:Die Komplikationsraten betrugen 1,4% für Wundinfektionen und 5,6% für Blutungen. Das mediane krankheitsspezifische Überleben lag bei 14,9 Monaten (Gliome III) und 14,2 Monaten (GBM). Die 2-Jahres-Überlebensraten betrugen 26,9% (Gliome III) und 6,8% (GBM; p = 0,0296). Der Resektionsstatus hatte keinen signifikanten Einfluss (p = 0,0741), ebenso wenig Alter, Geschlecht, Lokalisation, Allgemeinzustand, Größe, Primärtumor versus Rezidiv und Bestrahlungsdosis. Ein Vergleich mit einem konventionell behandelten Patientenkollektiv zeigte keine signifikante Verbesserung des Überlebens. 3 Monate nach Therapie hatten sich die initialen Symptome in 59% (Hemiparese), 50% (Aphasie), 50% (Hemianopsie) und 60% (Krampfanfälle) gebessert.Schlussfolgerung:Die IORT ist gut durchführbar; die perioperative Komplikationsrate war nicht erhöht. Das Überleben konnte im Vergleich zu einer historischen Kontrollgruppe insgesamt nicht verbessert werden. Rezidive erzielten dasselbe Überleben wie Primärtumoren, und auch GBM erreichten ein etwas besseres Überleben; diese beiden Gruppen sind am ehesten mögliche Indikationen für die IORT.

Radiotherapy of benign diseases-scleredema adultorum Buschke.

Background:Scleredema adultorum Buschke is a rare disorder characterized by thickening of the dermis of the neck, head and upper trunk. Its etiology is unknown, but there may be a preceding history of infection and there is a known association with diabetes mellitus. Women are more frequently affected. Usually, the disease is self-limiting but some patients show progressive disease. In these cases therapeutic options are poor, with only case reports and small series supporting their use.Case Report:A 58-year-old patient with a scleredema of the neck and upper trunk is described, who was treated twice within 6 months by electron-beam radiation therapy. After the second course his symptoms improved significantly. A review of the literature of radiation treatment of this disease is given.Conclusion:Regardless of the possible mechanisms in pathogenesis and treatment of scleredema adultorum Buschke, the application of ionizing radiation is an important, effective and well-tolerated therapy option in the treatment of severe cases and may candidate as the first-line treatment of this disease.Hintergrund:Das Skleroedema adultorum Buschke ist eine seltene Erkrankung, die u.a. durch eine ödematöse Schwellung der Haut des Nackens, des Kopfes und des oberen Stammes charakterisiert ist. Die Ätiologie der Erkrankung ist unklar. Es scheint einen Zusammenhang mit einem vorausgegangenen viralen oder bakteriellen Infekt bzw. einer Diabetes-mellitus-Erkrankung zu geben. Häufiger wird das weibliche Geschlecht betroffen. Gewöhnlich ist die Erkrankung selbstlimitierend, aber einige Patienten zeigen einen kontinuierlich fortschreitenden Verlauf. Für diese schwerwiegenden Fälle ist keine etablierte Behandlung bekannt. Die empfohlenen Therapien basieren hauptsächlich auf Fallberichten bzw. Therapieserien mit kleinen Fallzahlen, die einen Behandlungsvorteil in der jeweiligen individuellen Situation zeigten.Fallbericht:Beschrieben wird ein 58-jähriger Patient mit Sklerödem des Nackens und des oberen Stammes, der innerhalb von 6 Monaten zweimal mittels schneller Elektronen bestrahlt wurde. Nach der zweiten Therapieserie kam es zu einer deutlichen Besserung der klinischen Symptomatik. Eine Literaturübersicht über die Behandlung der Erkrankung mittels Radiotherapie wird gegeben.Schlussfolgerung:Unabhängig von dem möglichen Mechanismus der Pathogenese und der Therapie der Erkrankung stellt die Applikation ionisierender Strahlung in schwerwiegenden Fällen eine wichtige, effektive und gut verträgliche Therapie dar und sollte bei diesen Patienten als Therapie der ersten Wahl diskutiert werden.

CT simulation in nodal positive breast cancer.

Background: A variety of solutions are used to match tangential fields and opposed lymph node fields in irradiation of nodal positive breast cancer. The choice is depending on the technical equipment which is available and the clinical situation. The CT simulation of a non-monoisocentric technique was evaluated in terms of accuracy and reproducibility. Patients, Material and Methods: The field match parameters were adjusted virtually at CT simulation and were compared with parameters derived mathematically. The coordinate transfer from the CT simulator to the conventional simulator was analyzed in 25 consecutive patients. Results: The angles adjusted virtually for a geometrically exact coplanar field match corresponded with the angles calculated for each set-up. The mean isocenter displacement was 5.7 mm and the total uncertainty of the coordinate transfer was 6.7 mm (1 SD). Limitations in the patient set-up became obvious because of the steep arm abduction necessary to fit the 70 cm CT gantry aperture. Required modifications of the arm position and coordinate transfer errors led to a significant shift of the marked matchline of > 1.0 cm in eight of 25 patients (32%). Conclusion: The virtual CT simulation allows a precise and graphic definition of the field match parameters. However, modifications of the virtual set-up basically due to technical limitations were required in a total of 32% of cases, so that a hybrid technique was adapted at present that combines virtual adjustement of the ideal field alignment parameters with conventional simulation.Hintergrund: Für den Feldanschluss zwischen Brusttangenten und ventrodorsal opponierenen Lymphknotenfeldern bei der Bestrahlung des nodal positiven Mammakarzinoms sind verschiedene Methoden in Gebrauch, wobei für die Auswahl technische und klinische Gegebenheiten maßgeblich sind. Die CT-Simulation einer nicht monoisozentrischen Technik wird in dieser Untersuchung hinsichtlich Genauigkeit und Reproduzierbarkeit geprüft. Patienten, Material und Methode: Feldanschlussparameter wurden mit virtueller Simulation erstellt und mit errechneten Werten verglichen. Der Koordinatentransfer vom CT-Simulator zum konventionellen Simulator wurde bei 25 aufeinanderfolgenden Patienten analysiert. Ergebnisse: Virtuell eingestellte und berechnete Winkel stimmten exakt überein. Die totale Unsicherheit des Koordinatentransfers war 6,7 mm (1 SD) und die mittlere Isozentrumsabweichung der Tangenten betrug 5,7 mm. Einschränkungen der möglichen Patientenlagerung waren auf den beschränkten CT-Gantry-Durchmesser von 70 cm zurückzuführen, die nur eine steile Armhaltung ermöglichte. Notwendige Änderungen der Armposition und Fehler im Koordinatentransfer machten eine signifikante Verschiebung der Anschlusslinie über 1,0 cm bei acht Patientinnen (32%) erforderlich. Schlussfolgerung: Die virtuelle CT-Simulation ermöglicht eine genaue und anschauliche Definition der Feldanschlussparameter. Modifikationen dieser Parameter waren jedoch bei acht von 25 (32%) Patientinnen im Wesentlichen aufgrund von gerätetechnischen Einschränkungen erforderlich, sodass derzeit eine “Hybridtechnik” durchgeführt wird, welche die virtuelle Erstellung der Parameter mit der konventionellen Simulation verbindet.

A case of radiotherapy for an advanced bronchial carcinoma patient with implanted cardiac rhythm machines as well as heart assist device

We present a case of radiotherapy for a 66-year-old patient with squamous cell carcinoma on the left main bronchus undergoing implantation of pacemaker, implantable cardioverter defibrillator (ICD) as well as cardiopulmonary support (CPS) device. The radiation area was determined according to 4D List Mode positron emission tomography–computed tomography (PET-CT) data. Planning Target Volume (PTV) included a part of the active ICD. For the optimal tumor coverage and sparing of both the implantable cardiac devices and organs at risk, we combined the conformal radiotherapy with stereotactic body radiotherapy (SBRT) using helical tomotherapy. The prescription dose of 25.2Gy was applied by conventional radiotherapy. SBRT was performed hypofractionated with a prescription dose of 35Gy in 5 fractions. A dynamic electrocardiogram was performed during every radiation fraction. The implanted aggregates were checked three times a week. Despite partial localization of the active ICD in the radiation field, the tumor was treated without inappropriate shock delivery during radiation treatment and over twelve months afterwards. The reduced tumor size as well as tumor metabolic activity were observed by PET-CT three months after radiation treatment. The patient exhibited no signs of pneumonitis on the last radiological follow-up examination six months after radiotherapy. The reduced dyspnea and cough over the first four months after treatment were observed.In conclusion, tumor shrinkage and temporary clinical improvement of the patient as well as no technical complications of implanted cardiac devices were achieved by the radiation treatment.

9 years tumor free survival after resection, intraoperative radiotherapy (IORT) and whole brain radiotherapy of a solitary brain metastasis of non-small cell lung cancer

Overall five-year survival for patients in NSCLC clinical stage IV is lower than 5% [1], in surgical stage IV (histologically proven distant metastases) nearly 0%. For patients with brain metastases in general, one-year survival amounts to about 10 /20% after whole-brain radiotherapy (WBRT) [2]. Several attempts to improve local control of brain metastases have been made, including dose escalation (RTOG 85 / 28). No significant difference in survival was found, median survival amounted to 3 /6 months [3]. In recent years, stereotactic radiosurgery has gained importance. One to three metastases of a suitable size (5/4 cm) may be an indication for stereotactic radiosurgery [4,5]. Electron beam intraoperative radiotherapy (IORT) for patients with malignant brain tumors has been performed at our institution since May 1992 [6]. Only few patients with brain metastases have been treated so far. We report a case of longterm control by surgery, IORT and WBRT. In October 1995, a 36-year old female patient (smoker) presented with the accidental diagnosis of a mass in the left upper lobe. CT and bronchoscopy confirmed the suspicion. Histology showed adenocarcinoma grade 1 /2. The tumor was clinically staged as T2N2M0 (stage IIIA). The patient was then recruited for the Muenster lung cancer trial [7]. She received three cycles of neoadjuvant CE chemotherapy followed by combined hyperfractionated radiochemotherapy with 45 Gy, carboplatin and vindesine. Under this regimen, a good partial remission was achieved. Besides a slight dysphagia, no further acute side effects were observed. She then underwent a radical resection (R0) of the left upper lobe with mediastinal lymphadenectomy (pathological tumor stage: ypT1N0G1 /2, SalzerKuntschik grade III). Ten months after the initial diagnosis she experienced severe headaches and scintillations. CT and MRI showed a solitary brain metastasis in the right occipital lobe with a diameter of about 2.5 cm. No further metastases or local recurrence were detected. It was then decided to perform a resection of this metastasis with IORT. No macroscopic residual tumor was left. IORT was carried out at a nondedicated facility with 14 MeV electrons from a linear accelerator using a 5 cm round cone [6]. The applied IORT dose was 20 Gy relative to the 90% isodose. After surgery and IORT, WBRT was done with a dose of 30 Gy in 10 fractions. Three years later, MRI showed a newly developed contrast enhancing structure in the right occipital lobe. Brain SPECT with Tl-201 and I-123-AMT showed a focal tracer uptake with an elevated tumor/ non-tumor ratio. F-18-FDG-PET showed a moderate glucose hypermetabolism. These findings were suspect for tumor recurrence. Because of the possible differential diagnosis of brain necrosis and

In-vivo dosimetric analysis in total skin electron beam therapy

Background and purpose Thermoluminescent dosimetry (TLD) is an important element of total skin electron beam therapy (TSEBT). In this study, we compare radiation dose distributions to provide data for dose variation across anatomic sites. Materials and methods Retrospectively collected data on 85 patients with cutaneous lymphoma or leukemia underwent TSEBT were reviewed. Patients were irradiated on two linear accelerators, in one of two positions (standing, n = 77; reclined, n = 8) and 1830 in vivo TLD measurements were obtained for various locations on 76 patients. Results The TLD results showed that the two TSEBT techniques were dosimetrically heterogeneous. At several sites, the dose administered correlated with height, weight, and gender. After the first TLD measurement, fourteen patients (18%) required MU modification, with a mean 10% reduction (range, −25 to +35). Individual TLD results allowed us to customize the boost treatment for each patient. For patients who were evaluated in the standing position, the most common underdosed sites were the axilla, perineum/perianal folds, and soles (each receiving 69%, 20%, and 34% of the prescribed dose, respectively). For patients evaluated in a reclining position, surface dose distribution was more heterogeneous. The sites underdosed most commonly were the axilla and perineum/perianal folds (receiving less than one third of prescribed dose). Significant variables were detected with model building. Conclusion TLD measurements were integral to quality assurance for TSEBT. Dose distribution at several anatomical sites correlated significantly with gender, height, and weight of the treated individual and might be predicted.