Dosimetric verification of dose optimisation algorithm during endovascular brachytherapy of the peripheral vessels

AbstractAimDosimetric verification of the dose optimisation model used in endovascular brachytherapy, evaluation of the optimised dose distributions using elaborated indices.BackgroundThe equipment used for standard radiotherapy is used in vascular brachytherapy for prevention of restenosis after angioplasty.Material and MethodA paraffin-wax phantom, thermoluminescent detectors and MD-55 Gafchromic® films were used for dose measurements. The edge dose index (EDI), central dose index (CDI) and treatment length index (TLI) were introduced to compare dose distributions calculated and measured.ResultsObtained values (p>0.05) show no statistically significant differences between calculated doses and measured doses. EDI values showed improvement in dose homogeneity on the edges of the application after optimisation. After optimisation CDI values from 0.9% to 1.6% for calculated and from −1.8% to 3.1% for measured showed improvement in dose homogeneity in the central part of the application. Observed values of TLI from 3% to 21% for calculated doses and from 7% to 24% for doses measured by Gafchromic® films showed increase of RIL for optimised treatment plans.Conclusions1/ The designed phantom allowed repeatable dosimetric verification of dose distributions in endovascular brachytherapy. 2/ Measurements with thermoluminescent detectors and Gafchromic films proved the accuracy of the calculation algorithm in endovascular brachytherapy conditions. 3/ Elaborated indices were found to be a useful tool in describing dose homogeneity. They allowed the process of optimisation to be controlled and thus an increase in dose homogeneity by 30% at the edges and by 7% in the middle of the treated volume to be achieved

Dosimetric verification of the dose calculation algorithms in real time prostate brachytherapy

BackgroundDuring real time prostate brachytherapy different calculation algorithms can be used which gives the opportunity to modulate the dwell times and positions of the source and consequently the dose distribution and values of therapeutic indices [1].AimThe aim of this study was the dosimetric verification (in-phantom) of three optimization algorithms for dose calculation during real-time prostate brachytherapy.Materials/MethodsThree optimization algorithm were evaluated: geometric optimization (GO), inverse optimization (IO) and blind inverse optimization (BIO). Then treatment plans for the tissue-equivalent phantom were prepared. For each plan the same CTV, organs at risk (OARs: urethra, rectum), number of needles and geometry of implant were used.ResultsMeasured mean doses and their standard deviations for GO, IO and BIO were respectively: 11.13 Gy and 0.01 Gy, 15.71 Gy and 0.01 Gy, 14.74 Gy and 0.02 Gy for the urethra and 10.11 Gy and 0.01 Gy, 8.97 Gy and 0.01 Gy, 8.70 Gy and 0.01 Gy for the rectum. Comparison between doses measured by semiconductor detectors and calculated doses revealed differences in the range from 0.10 Gy between doses compared in the urethra for IO and BIO even to 2.46 Gy for GO for the same analyzed organ. For the rectum these differences were between 0.32 and 0.66 Gy.ConclusionsQualitative comparative analysis performed for a phantom study for 3D-CBRT prostate treatment proved the correctness of verified optimization algorithms implemented in Oncentra Prostate vs. 3.0.9

Dosimetric verification of dose optimisation algorithm during endovascular brachytherapy of the peripheral vessels

AimDosimetric verification of the dose optimisation model used in endovascular brachytherapy, evaluation of the optimised dose distributions using elaborated indices.BackgroundThe equipment used for standard radiotherapy is used in vascular brachytherapy for prevention of restenosis after angioplasty.Material and MethodA paraffin-wax phantom, thermoluminescent detectors and MD-55 Gafchromic® films were used for dose measurements. The edge dose index (EDI), central dose index (CDI) and treatment length index (TLI) were introduced to compare dose distributions calculated and measured.ResultsObtained values (p>0.05) show no statistically significant differences between calculated doses and measured doses. EDI values showed improvement in dose homogeneity on the edges of the application after optimisation. After optimisation CDI values from 0.9% to 1.6% for calculated and from −1.8% to 3.1% for measured showed improvement in dose homogeneity in the central part of the application. Observed values of TLI from 3% to 21% for calculated doses and from 7% to 24% for doses measured by Gafchromic® films showed increase of RIL for optimised treatment plans.Conclusions1/ The designed phantom allowed repeatable dosimetric verification of dose distributions in endovascular brachytherapy. 2/ Measurements with thermoluminescent detectors and Gafchromic films proved the accuracy of the calculation algorithm in endovascular brachytherapy conditions. 3/ Elaborated indices were found to be a useful tool in describing dose homogeneity. They allowed the process of optimisation to be controlled and thus an increase in dose homogeneity by 30% at the edges and by 7% in the middle of the treated volume to be achieved

Accelerated Partial Breast Irradiation in the treatment of breast cancer — current status and treatment methods

Podstawowym powodem opracowania techniki przyspieszonego częściowego napromieniania raka piersi (AcceleratedPartial Breast Irradiation — APBI) było założenie, że prowadzi ono do uzyskania równorzędnego odsetkakontroli miejscowej wraz z mniejszą toksycznością leczenia w porównaniu z napromienianiem całej piersi wiązkamizewnętrznymi (Whole Breast Radiation Therapy — WBRT) po chirurgicznym leczeniu oszczędzającym (Breast ConservingSurgery — BCS). Jest to metoda radioterapii skierowana do wyselekcjonowanej grupy pacjentek we wczesnej faziezaawansowania choroby. Głównym powodem wprowadzenia do praktyki klinicznej APBI było niskie ryzyko wznowymiejscowej w tej samej piersi poza pierwotnie zajętym kwadrantem. Opublikowano szereg badań sugerującychmożliwość rezygnacji z WBRT. Dotychczas dostępne są wyniki 3 badań randomizowanych i 19 nierandomizowanych,w których badano skuteczność APBI. W poszczególnych badaniach klinicznych stosowano różne techniki APBI, dawkii frakcjonowanie, ale zasadnicza różnica w stosowanych technikach dotyczyła określenia obszaru do napromieniania(Clinical Target Volume — CTV i Planning Target Volume — PTV). Obecnie czekamy na wyniki siedmiu randomizowanychbadań klinicznych dotyczących zastosowania APBI w raku piersi po leczeniu oszczędzającym. W artykule dokonanoprzeglądu stosowanych technik, zasad kwalifi kacji oraz wyników leczenia metodą APBI.Breast conserving surgery (BCS) with following radiotherapy (EBRT) of the conserved breast became widely acceptedin the last decades for the treatment of early invasive breast cancer. The standard technique of EBRT after BCS is totreat the whole breast up to a total dose of 45 Gy to 50 Gy. Additional dose is given to the treated volume after EBRTto boost a portion of the breast to a higher dose. However, over the past 10 years, the application of radiotherapy inbreast cancer has changed. In early stage breast cancer, research has shown that the area requiring radiation treatmentto prevent the cancer from local recurrence is the breast tissue that surrounds the area where the initial cancerwas removed. Because this typically includes only a part of the breast, APBI is now used to treat the targeted portionof the breast and as a result allows accelerated delivery of the radiation dose in four to fi ve days. Published resultsof APBI techniques are very promising. In this article the current status, indications, technical aspects and recentlypublished results of APBI in breast cancer treatment are presented

Treatment of advanced lung cancer by external beam radiotherapy and high dose rate (HDR) brachytherapy

PurposeBrachytherapy is a highly valued and effective palliative treatment for lung cancer, especially as it reduces intensity of dyspnoea and other symptoms arising from tumours inside the respiratory tract. In some cases, due to the location of the lesion brachytherapy is a treatment of choice. However, its curative role is unclear. A combination treatment of brachytherapy and an external beam irradiaton may play a significant role when the mediastinal lymph nodes are involved.The paper presents the results of treatment of advanced lung cancer patients by external beam irradiation and brachytherapy, and the role of this palliative treatment is discussed.Material and methodsBetween May 1999 and March 2000 at the Greatpoland Cancer Centre fifteen patients with advanced lung cancer were treated by HDR brachytherapy and palliative external beam irradiation using the method of hypofractionation. The patients’ age ranged between 39 to 80 years, mean: 54.3 years. The treatment consisted of external beam irradiation (total dose of 20–30 Gy), and a weekly high dose rate (HDR) brachytherapy (three fractions of 7.5 or 10 Gy, at 1 cm from the source). In three cases the treatment was started with external irradiation, whereas in 12 cases the first stage was brachytherapy. During the patients’ clinical and endobronchial follow-up of 1, 3 and 6 months, local remission and regression of difficulties in breathing, cough, pain and haemoptysis were assessed.ResultsIn all our patients subjective improvement (regression of all symptoms) was found on the first check-up following treatment. In one case complete remission of the tumour lasted for over 6 months, in 9 cases partial remission and in two cases progression were found. Severe complications due to the high total local dose were not observed.ConclusionsCombined palliative treatment (intraluminal brachytherapy and external beam irradiation) in advanced lung cancer was an efficient method that led to regression of symptoms and improvement of well-being in many patients

High dose rate endobronchial brachytherapy in the management of advanced lung cancer – comparison of different doses – preliminary assessment

PurposeBrachytherapy is one of the most efficient methods of overcoming endobronchial obstruction in palliative treatment of lung cancer. In single cases, brachytherapy is performed as radical treatment, however in most of cases, due to advanced clinical stage it has a palliative aim. In the absence of clear consensus regarding the value of doses used in brachytherapy different fraction doses are used in clinical treatment. The aim of this work is to compare results of palliative high dose rate brachytherapy using various treatment protocols with the view to analysing differences in survival and diminishing breathing difficulties.Material and methodsBetween May 1999 and February 2000 at the Greatpoland Cancer Center, 69 patients with advanced lung cancer were treated by high dose rate brachytherapy. They were disqualified from radical treatment due to advanced clinical stage. The age of the patients ranged from 39 to 76 years (average 53,2 years). Fifty-one patients received a total dose of 22,5 Gy in 3 fractions once a week, 18 patients received one single fraction of 10 Gy. All the patients were divided into two groups according to their clinical stage and the Karnofsky score – those with the Karnofsky score lower than 50 were qualified for a single fraction treatment. They were under clinical and endobronchial observation as regards survival rates, local remission and subsiding dyspnoea, breathing, cough and haemoptysis in the first, third, sixth and twelveth month of observation.ResultsFour weeks after the end of treatment subjective improvement (subsidence of all symptoms) was ascertained in 61/69 (88,4%) patients. In 12 cases (17,4%) complete remission (CR), in 49 cases (71,0%) – partial remission (PR) of the tumor were found. During one year of observation 45 (65,2%) patients died, in 10 cases (14,5%) improvement of in dyspnoea was observed and in 14 cases (20,3%) recurrence and progression of the disease were noted. There was no statistical difference in the survival rates between the two groups of patients treated with different fractions protocols.Conclusions1.Brachytherapy in advanced lung cancer is an efficient method that led in most of patients to subcidence of symptoms and to improvement of the quality their lives.2.The two treatment protocols showed similar efficiency in overcoming difficulties in breathing.3.Survival rates were similar in both group of patients treated with different treatment protocols

Patterns of care for brachytherapy in Europe (PC BE) in Spain and Poland: Comparative results

BackgroundCancer incidence and its mortality depend on a number of factors, including age, socio-economic status and geographic situation, and its incidence is growing around the world [1]. Cancer incidence in Europe is now about 4000 patients per million per year and due to the ageing population a yearly increase of 1–1.5% in cancer cases is estimated in the next two decades [2–4]. Most of the cancer treatments will include external beam radiotherapy or brachytherapy. Brachytherapy has increased its use as a radical or palliative treatment and become more sophisticated with the spread of pulsed dose rate and high dose rate afterloading machines, and the use of new planning systems has additionally improved quality of treatment [5–14]AimThe aim of the present study was to compare two countries (Poland and Spain) and to report the differences in the use of brachytherapy in these countries. For this reason, several characteristics related to brachytherapy were compared.Materials/MethodsThe data used were collected using a website questionnaire for the year 2002 where every centre that participated in the survey could introduce, change or update the information requested. Hospitals included in the study were those that provided data on brachytherapy, because our objective was to compare the brachytherapy facilities between Poland and Spain.ResultsData were available for 22 centres in Poland and 39 centres in Spain that provided brachytherapy in 2002. Spain having more centres that applied brachytherapy (1.0 centre per 1,000,000 inhabitants in Spain vs. 0.6 centre per 1,000,000 inhabitants in Poland), the average number of brachytherapy patients per centre is lower in Spain than in Poland, 137 and 382 respectively. The 5 main tumour sites treated with brachytherapy in Poland were: gynaecological (73.7%), bronchus (13.0%), breast (2.8%), prostate (2.4%) and head and neck (1.6%). In Spain they were: gynaecological (59.7%), breast (15.4%), prostate (12.8%), head and neck (4.2%) and bronchus (1.5%). Statistically significant differences were found in the number of gynaecological, bronchial and breast brachytherapy patients between the countries.ConclusionsAlthough both countries belong to the European Union, there were observed several differences in the use of brachytherapy. We also found some differences in the brachytherapy techniques used in prostate and head and neck cancers

Leczenie restenozy w stencie za pomocą brachyterapii wewnątrzwieńcowej. Obserwacja 9-miesięczna 51 pacjentów

Wstęp: Restenoza po zabiegach angioplastyki wieńcowej, mimo stosowania coraz nowszych metod leczenia, nadal jest jednym z głównych problemów kardiologii interwencyjnej. Celem pracy jest ocena odległego rokowania u pacjentów z restenozą w stencie (ISR), leczonych metodą brachyterapii wewnątrzwieńcowej (VBT) typu "beta", przy użyciu izotopu fosforu P32. Materiał i metody: W latach 2002-2003 leczono 51 chorych z ISR w natywnych naczyniach wieńcowych metodą VBT promieniami beta. U wszystkich pacjentów po wcześniejszym zabiegu stentowania stwierdzono nawrót dolegliwości dławicowych oraz dodatni wynik próby wysiłkowej. Restenozę potwierdzono za pomocą badania angiograficznego (redukcja światła naczynia > 50%). U wszystkich chorych bezpośrednio przed napromieniowaniem wykonywano rutynowy zabieg angioplastyki balonowej. Brachyterapię wykonywano, stosując system Galileo ™ firmy Guidant, w którym źródło promieniowania stanowi izotop fosforu P32. Obserwację odległą wraz z koronarografią po 6-9 miesiącach przeprowadzono u wszystkich pacjentów. Wyniki: W okresie obserwacji nie odnotowano zgonów, u 1 chorego wystąpił zawał serca spowodowany późną zakrzepicą w stencie (2%). W koronarografii w 7 przypadkach (13,7%) stwierdzono nawrót restenozy w obrębie samego stentu, a w dodatkowych 2 (3,9%) w odcinku bezpośrednio przylegającym do stentu (restenoza brzeżna). Zatem łącznie po 9 miesiącach u 10 pacjentów zabieg brachyterapii okazał się nieskuteczny (19,6%). U osób tych częściej obserwowano złożoną postać restenozy (typ III i IV). Wnioski: Brachyterapia jest skuteczną i bezpieczną metodą leczenia restenozy w stencie. Ryzyko wystąpienia kolejnej restenozy po brachyterapii wewnątrzwieńcowej jest większe u chorych z rozlanym typem restenozy. (Folia Cardiol. 2004; 11: 727-732

Leczenie restenozy w stencie za pomocą brachyterapii wewnątrzwieńcowej. Obserwacja 9-miesięczna 51 pacjentów

Wstęp: Restenoza po zabiegach angioplastyki wieńcowej, mimo stosowania coraz nowszych metod leczenia, nadal jest jednym z głównych problemów kardiologii interwencyjnej. Celem pracy jest ocena odległego rokowania u pacjentów z restenozą w stencie (ISR), leczonych metodą brachyterapii wewnątrzwieńcowej (VBT) typu "beta", przy użyciu izotopu fosforu P32. Materiał i metody: W latach 2002-2003 leczono 51 chorych z ISR w natywnych naczyniach wieńcowych metodą VBT promieniami beta. U wszystkich pacjentów po wcześniejszym zabiegu stentowania stwierdzono nawrót dolegliwości dławicowych oraz dodatni wynik próby wysiłkowej. Restenozę potwierdzono za pomocą badania angiograficznego (redukcja światła naczynia > 50%). U wszystkich chorych bezpośrednio przed napromieniowaniem wykonywano rutynowy zabieg angioplastyki balonowej. Brachyterapię wykonywano, stosując system Galileo ™ firmy Guidant, w którym źródło promieniowania stanowi izotop fosforu P32. Obserwację odległą wraz z koronarografią po 6-9 miesiącach przeprowadzono u wszystkich pacjentów. Wyniki: W okresie obserwacji nie odnotowano zgonów, u 1 chorego wystąpił zawał serca spowodowany późną zakrzepicą w stencie (2%). W koronarografii w 7 przypadkach (13,7%) stwierdzono nawrót restenozy w obrębie samego stentu, a w dodatkowych 2 (3,9%) w odcinku bezpośrednio przylegającym do stentu (restenoza brzeżna). Zatem łącznie po 9 miesiącach u 10 pacjentów zabieg brachyterapii okazał się nieskuteczny (19,6%). U osób tych częściej obserwowano złożoną postać restenozy (typ III i IV). Wnioski: Brachyterapia jest skuteczną i bezpieczną metodą leczenia restenozy w stencie. Ryzyko wystąpienia kolejnej restenozy po brachyterapii wewnątrzwieńcowej jest większe u chorych z rozlanym typem restenozy. (Folia Cardiol. 2004; 11: 727-732