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1

Complexity analysis of VMAT prostate plans: insights from dimensionality reduction and information theory techniques

Kamperis Efstathios, Kodona Chionia, Papalexandrou Apostolia, Arsos Georgios, Heidich Anna-Bettina, Hatziioannou Konstantinos, Giannouzakos Vasileios, Papanastasiou Emmanouil

Polish Journal of Medical Physics and Engineering

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2023

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Vol. 29, Iss. 3

143--150

EN

Introduction: Volumetric Modulated Arc Therapy (VMAT) is a state-of-the-art prostate cancer treatment, defined by high dose gradients around targets. Its unique dose shaping incurs hidden complexity, impacting treatment deliverability, carcinogenesis, and machine strain. This study compares various aperture-based VMAT complexity indices in prostate cases using principal component and mutual information analyses. It suggests essential properties for an ideal complexity index from an information-theoretic viewpoint. Material and methods: The following ten complexity indices were calculated in 217 VMAT prostate plans: circumference over area (CoA), edge metric (EM), equivalent square field (ESF), leaf travel (LT), leaf travel modulation complexity score for VMAT (LTMCSV), mean-field area (MFA), modulation complexity score (standard MCS and VMAT variant MCSV), plan irregularity (PI), and small aperture score (SAS5mm). Principal component analysis (PCA) was applied to explore the correlations between the metrics. The differential entropy of all metrics was also calculated, along with the mutual information for all 45 metric pairs. Results: Whole-pelvis plans had greater complexity across all indices. The first three principal components explained 96.2% of the total variance. The complexity metrics formed three groups with similar conceptual characteristics, particularly ESF, LT, MFA, PI, and EM, SAS5. The differential entropy varied across the complexity metrics (PI having the smallest vs. EM the largest). Mutual information analysis (MIA) confirmed some metrics’ interdependence, although other pairs, such as LTMCSV/SAS5mm, LT/MCSV, and EM/SAS5mm, were found to share minimal MI. Conclusions: There are many complexity indices for VMAT described in the literature. PCA and MIA analyses can uncover significant overlap among them. However, this is not entirely reducible through dimensionality reduction techniques, suggesting that there also exists some reciprocity. When designing predictive models of quality assurance metrics, PCA and MIA may prove useful for feature engineering.

2

Dosimetric impact of rotational set‑up errors in high-risk prostate cancer

Poncyljusz Maria, Bulski Wojciech

Polish Journal of Medical Physics and Engineering

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2022

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Vol. 28, Iss. 4

200--206

EN

Introduction: Cone-beam computed tomography (CBCT) provides an excellent solution to quantitative assessment and correction of patient set-up errors during radiotherapy. However, most linear accelerators are equipped with conventional therapy tables that can be moved in three translational directions and perform only yaw rotation. Uncorrected roll and pitch result in rotational set-up errors, particularly when the distance from the isocenter to the target border is large. The aim of this study was to investigate the impact of rotational errors on the dose delivered to the clinical target volume (CTV), the planning target volume (PTV) and organs at risk (OAR). Material and methods: 30 patients with prostate cancer treated with VMAT technique had daily CBCT scans (840 CBCTs in total) prior to treatment delivery. The rotational errors remaining after on-line correction were retrospectively analysed. The sum plans simulating the dose distribution during the treatment course were calculated for selected patients with significant rotational errors. Results: The dose delivered to the prostate bed CTV reported in the sum plan was not lower than in the original plan for all selected patients. For four patients from the selected group, the D98% for prostate bed PTV was less than 95%. The V47.88Gy for pelvic lymph nodes PTV was less than 98% for two of the selected patients. Conclusions: The analysis of the dosimetric parameters showed that the impact of uncorrected rotations is not clinically significant in terms of the dose delivered to OAR and the dose coverage of CTV. However, the PTV dose coverage is correlated with distance away from the isocenter and is smaller than planned.

3

Comparative pharmacokinetic study of bicalutamide administration alone and in combination with vitamin D in rats

Shi Wenjing, Di Haixiao, Pang Bo, Jin Huixin, Liu Hongtao, Qiu Bo, Ren Bingnan, Pang Guoxun

Acta Chromatographica

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2022

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Vol. 34, no. 4

453--460

EN

Bicalutamide (BCL) has been approved for treatment of advanced prostate cancer (Pca), and vitamin D is inevitably used in combination with BCL in Pca patients for skeletal or anti-tumor strategies. Therefore, it is necessary to study the effect of vitamin D application on the pharmacokinetics of BCL. We developed and validated a specific, sensitive and rapid UHPLC–MS/MS method to investigate the pharmacokinetic behaviours of BCL in rat plasma with and without the combined use of vitamin D. Plasma samples were extracted by protein precipitation with ether/dichloromethane (2:1 v/v), and the analytes were separated by a Kinetex Biphenyl 100A column (2.1 × 100 mm, 2.6 μm) with a mobile phase composed of 0.5 mM ammonium acetate (PH 6.5) in water (A) and acetonitrile (B) in a ratio of A:B = 35:65 (v/v). Analysis of the ions was run in the multiple reactions monitoring (MRM) mode. The linear range of BCL was 5–2000 ng mL⁻¹. The intra- and inter-day precision were less than 14%, and the accuracy was in the range of 94.4–107.1%. The mean extraction recoveries, matrix effects and stabilities were acceptable for this method. The validated method was successfully applied to evaluate the pharmacokinetic behaviours of BCL in rat plasma. The results demonstrated that the pharmacokinetic property of BCL is significantly affected by combined use of vitamin D, which might help provide useful evidence for the clinical therapy and further pharmacokinetic study.

4

Zastosowanie technik laserowej desorpcji/jonizacji w identyfikacji lipidów jako biomarkerów raka prostaty

Buszewska-Forajta Magdalena, Pomastowski Paweł Piotr, Maślak Ewelina, Fijałkowski Piotr, Buszewski Bogusław

Wiadomości Chemiczne

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2021

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[Z] 75, 7-8

893--909

EN

Mass spectroscopy has grown enormously over the past century and its variations are used in many fields. One of the methods used to ionize particles is to irradiate the sample with laser radiation. This methods are called laser desorption/ionization techniques and they have great potential for diagnostic applications. Thanks to the so-called soft ionization, direct analysis of a wide variety of compound classes can be used for rapid profiling. Lipids are a diverse group of metabolites that share a common feature of having a hydrophobic fragment. They play an important role in various cellular processes. Changes in lipidome correlate with the symptoms of various diseases. The observation of abnormalities in lipid metabolism is especially important in cancers diagnosed in many patients - such as prostate cancer. Monitoring the level of key biomarkers in the development of a given disease will allow for an earlier correct diagnosis and the use of individual treatment. This short review presents the issues of prostate cancer and the applicability of laser desorption/ionization techniques to identify lipid biomarkers that can be used for rapid identification.

5

Comparison of helical tomotherapy with multi-field intensity-modulated radiotherapy treatment plans using simultaneous integrated boost in high-risk prostate cancer

Başaran Hamit, Karaca Sibel, Koca Timur, Gündoğdu Yasemin Örs

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 2

143--149

EN

Purpose: The aim of this study is to compare the dosimetric results of Helical Tomotherapy (HT) and Multi-field IMRT treatment plans using a Simultaneous Integrated Boost (SIB) technique in the treatment of High-Risk Prostate Cancer (HRPCa) with pelvic nodal radiation. Methods: Seventeen patients planned with HT and 7,8 and 9 fields IMRT were investigated. All plans were designed with the prescribed dose of 54.0 Gy to the PTVln while simultaneously delivering 74.0 Gy to the PTVPS in 30 fractions. Dosimetric data of PTV and OARs were compared. Results: HT gives a better CI and HI of PTVPS compared to multi-field IMRT plans. HT plans significantly improved target coverage (HT:0.95 vs multi-field IMRT: 0.52, 0.49 and 0.49 respectively, p < 0.001). Bladder mean dose(Gy) (HT: 45.6 vs multi-field IMRT: 53.6, 53.3 and 52.7 respectively, p = 0.004) and D66%(Gy) dose (HT: 35.3 vs multi-field IMRT: 46.7, 47.0 and 44.9 respectively, p = 0.006) were lower in HT. But multi-field IMRT plans significantly reduced the rectum volume receiving more than 75 Gy ; (HT V75% (%) 2.7 vs multi-field IMRT 0.8, 1.4 and 0.9 respectively, p = 0.008). HT provided better sparing of the right and left femoral head receiving a mean dose. The penile bulb and small bowel doses were the highest in HT compared with multi-field IMRT. Conclusions: HT achieved better dose distribution to target compared to multi-field IMRT. This study suggests HT as a reasonable option for the treatment of HRPCa patients.

6

Szczęście i ciężka praca w opracowywaniu leków

Koroniak Łukasz

Wiadomości Chemiczne

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2020

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[Z] 74, 3-4

135--144

EN

Luck is one of the critical factors determining outcome of many activities we are involved in. In chemistry, and specifically in drug discovery a strike of luck can determine a successful study outcome leading to an approval of potentially blockbuster drug consequently offering a new treatment option for patients in need. On the other hand, lack of luck can often result in termination of activities, wasted resources and years of studies and often have negative impact on a fate of companies and its employees. In a similar fashion, hard work is critical for one’s success. It is not meant in a literal fashion, but rather from the perspective of “going the extra mile” in scientific research and development. It is meant as a proper approach to analysis of study outcome and understanding the reasons “why”, rather than accepting simply yes/no outcomes. Below article discusses two instances where certain level of luck and extra effort invested in understanding of widely available results led to development of two novel therapeutics in oncology field. Described stories deal with development of Abraxane, novel formulation of paclitaxel commercialized by Abraxis Bioscience as well as enzalutamid (Xtandi®) discovered at UCLA and developed and commercialized by Medivation and Astellas Pharma.

7

Propozycja strategii postępowania z planami leczenia dla akceleratorów liniowych o różnej konstrukcji kolimatora

Charmacińska Magdalena, Skrobała Agnieszka, Styś Sara, Pawałowski Bartosz

Inżynier i Fizyk Medyczny

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2020

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Vol. 9, nr 5

375--381

PL

Wprowadzenie W codziennej pracy ośrodka radioterapeutycznego nieuniknione są przerwy w działaniu aparatów spowodowane awariami lub przeglądami akceleratorów medycznych. W celu zachowania ciągłości leczenia pacjenci napromieniani są na innych dostępnych w ośrodku aparatach. Ze względu na to, że każdy z radioterapeutycznych planów leczenia dostosowany jest do aparatu, na którym plan ma być realizowany, koniecznym jest przygotowywanie zastępczych planów leczenia na pozostałe aparaty. Cel Celem pracy było zaproponowanie strategii postępowania z radioterapeutycznym planem leczenia w technice VMAT (ang. Volumetric Modulated Arc Therapy), tzw. planem oryginalnym w przypadku niedostępności aparatu źródłowego na przykładzie pacjentów z nowotworem stercza. Materiał i metoda Do badań zostały włączone trzy akceleratory firmy Varian znajdujące się w jednym centrum onkologii: TrueBeam, Clinac 2300 CD-S oraz Unique, posiadające 120-listkowy kolimator wielolistkowy MLC Millenium. Do przeprowadzenia badania zebrano grupę 24 pacjentów z rakiem stercza. Porównano plany leczenia pod względem liczby jednostek monitorowych oraz dawek w objętości PTV i w narządach krytycznych. Plany zweryfikowano i przeanalizowano dozymetrycznie za pomocą metody gamma. Wyniki Różnice w liczbie jednostek monitorowych pomiędzy oryginalnymi i zastępczymi planami leczenia nie przekraczały akceptowalnej wartości 2%. Zaobserwowano brak różnic pomiędzy dawkami w objętości PTV. Różnica dawki w analizowanych narządach krytycznych nie przekraczała akceptowalnego progu 2%. Wszystkie plany leczenia uzyskały minimum 95% zgodności dla weryfikacji dozymetrycznych metodą współczynnika gamma. Wnioski Wykonane badanie potwierdza możliwość realizowania radioterapeutycznych planów leczenia wykonanych w technice VMAT zamiennie na trzech akceleratorach (TrueBeam, Clinac 2300 CD-S oraz Unique, Varian), posiadających 120-listkowy kolimator MLC Millenium, dla pacjentów z nowotworem stercza.

EN

Introduction In the routine clinical work in the radiotherapeutic center, there are interruptions of the medical accelerators caused by failures or maintenance. In order to maintain the continuity of treatment, patients are irradiated with other devices available at the center. Due to the fact that each of the radiotherapeutic treatment plans is adapted to the particular accelerator on which the plan is to be implemented, it is necessary to prepare alternative treatment plans for the other accelerators. Aim The aim of the study was to propose a strategy for dealing with a radiotherapeutic treatment plan in the VMAT technique (Volumetric Modulated Arc Therapy), the so-called original plan in case of unavailability of the source accelerators on the example of patients with prostate cancer. Material and methods The study included three Varian accelerators located in one oncology center: TrueBeam, Clinac 2300 CD-S and Unique, equipped with a 120-leaf MLC Millenium multi-leaf collimator. A group of 24 patients with prostate cancer was collected for the study. Treatment plans were compared in terms of the number of monitor units and doses for PTV volume and critical organs. The plans were verified and dosimetrically analyzed using the gamma method. Results The differences in the number of monitor units between the original and two backup treatment plans did not exceed the acceptable value of 2%. No dose difference was observed for PTV. The dose difference in the analyzed critical organs did not exceed the acceptable threshold of 2%. All treatment plans achieved a minimum of 95% agreement for dosimetric verification using the gamma method. Conclusion The results of this study confirm the possibility of implementing radiotherapeutic treatment plans made in the VMAT technique, alternately on three accelerators (TrueBeam, Clinac 2300 CD-S and Unique, Varian), with a 120-leaf MLC Millenium collimator, for patients with prostate cancer.

8

Częstość myślenia o chorobie nowotworowej – na przykładzie mieszkańców województwa podkarpackiego

Jarmakowicz Paulina

Inżynier i Fizyk Medyczny

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2020

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Vol. 9, nr 4

283--287

PL

Przeprowadzono ankietę w 316-osobowej, losowo wybranej grupie mieszkańców województwa podkarpackiego. Miała na celu określenie częstości myślenia o możliwości zachorowania na chorobę nowotworową przez respondentów oraz osoby im bliskie. Stwierdzono istotne statystycznie zależności w stosunku do płci, wieku, wykształcenia oraz miejsca zamieszkania.

EN

A survey was conducted in a 316-person randomly selected group of inhabitants of the Podkarpackie Voivodeship. It was aimed at determining the frequency of thinking about the possibility of developing cancer by respondents and people close to them. Statistically significant relationships were found in relation to sex, age, education and place of residence.

9

Evaluation of various common prostate IMRT techniques based on estimated tumor control and normal tissue complication probabilities in correlation with patients anatomical parameters derived from the CT scans

Banaei Amin, Hashemi Bijan, Bakhshandeh Mohsen, Mofid Bahram

Polish Journal of Medical Physics and Engineering

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2019

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Vol. 25, Iss. 1

35--41

EN

Background: The relationship between the prostate IMRT techniques and patients anatomical parameters has been rarely investigated. Objective: to evaluate various prostate IMRT techniques based on tumor control and normal tissue complication probability (TCP and NTCP) values and also the correlation of such techniques with patients anatomical parameters. Methods: Four IMRT techniques (9, 7 and 5 fields and also automatic) were planned on the CT scans of 63 prostate cancer patients. The sum of distances between the organs at risk (OARs) and target tissue and also their average joint volumes were measured and assumed as anatomical parameters. Selected dosimetric and radiobiological parameters (TCP and NTCP) values were compared among various techniques and the correlation with the above anatomical parameters were assessed using Pearsons’ correlation. Results: High correlations were found between the dosimetric/radiobiological parameters of OARs with the joint volumes and with the distances between the OARs and target tissue in all the techniques. The TCP and complication free tumor control probability (P+) values were decreased with increasing the joint volume and decreasing the distances between the OARs and target tissue (as poly-nominal functions). The NTCP values were increased with increasing the joint volumes and decreasing the distances (3-degree poly-nominal functions). For the low percent joint volumes (<20%) and high distances (>7 cm), The TCP, NTCP and P+ showed no statistical differences between various techniques (P-value>0.07). However, 9 and 7 fields techniques indicated better radiobiological results (P-value<0.05) in almost other ranges (>20% joint volumes and <7 cm distances). Conclusion: Based on our results, it would be possible to compare radiobiological effects of various common IMRT techniques and choose the best one regarding to patients anatomical parameters derived from the CT scans.

10

A Monte Carlo study on the radio-sensitization effect of gold nanoparticles in brachytherapy of prostate by 103Pd seeds

Jangjoo Amir Ghasemi, Ghiasi Hosein, Mesbahi Asghar

Polish Journal of Medical Physics and Engineering

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2019

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Vol. 25, Iss. 2

87--92

EN

103Pd seed is being used for prostate brachytherapy. Additionally, the dose enhancement effect of gold nanoparticles (GNP) has been reported in previous studies. The aim of this study was to characterize the dosimetric effect of gold nanoparticles in brachytherapy with a 103Pd source. Two brachytherapy seeds including 103Pd source was simulated using MCNPX Monte Carlo code. The seeds’ models were validated by comparing the MC with reported results. Then, GNPs (10 nm in diameter) with a concentration of 7mg Au/g were simulated uniformly inside the prostate of a humanoid computational phantom. Additionally, the dose enhancement factor (DEF) of nanoparticles was calculated for both modeled brachytherapy seeds. A good agreement was found between the MC calculated and the reported dosimetric parameters. For both seeds, an average DEF of 23% was obtained in tumor volume for prostate brachytherapy. The application of GNPs in conjunction with 103Pd seed in brachytherapy can enhance the delivered dose to the tumor and consequently leads to better treatment outcome.

11

Computer-aided diagnosis of clinically significant prostate cancer from MRI images using sparse autoencoder and random forest classifier

Abraham B., Nair M. S.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 3

733--744

EN

A novel method to diagnose clinically significant prostate cancer (PCa) using Multi-parametric Magnetic Resonance Imaging (mpMRI) biomarkers in a highly imbalanced dataset is investigated in this paper. Transaxial T2 Weighted (T2W), Apparent Diffusion Coefficient (ADC) and high B-Value (BVAL) Diffusion-Weighted (DW) images obtained from PROSTATEx 2016 challenge dataset publicly available in TCIA (The Cancer Imaging Archive) is used for this study. High-level features are extracted using a single layer Sparse Autoencoder (SAE). Synthetic Minority Oversampling Technique (SMOTE), Weka Resample algorithm and Adaptive Synthetic (ADASYN) sampling approach are explored to solve the class-imbalance problem. The performance of various classifiers are also investigated and it was found that the data augmented using ADASYN followed by classification using random forest classifier achieved the best performance. It achieved an area under ROC curve of 0.979. It also reached a Cohen's kappa score of 0.873, an accuracy of 93.65% and F-Measure of 0.94 in distinguishing clinically significant PCa from indolent Pca.

12

Zastosowanie systemów robotowych w leczeniu raka prostaty

Kroczek K.

Medical Robotics Reports

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2017

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vol. 6

8--14

PL

Rak prostaty jest drugą przyczyną zgonów wśród mężczyzn (Krajowy Rejestr Nowotworów). Wybór sposobu leczenia jest ściśle uzależniony od stanu zdrowia pacjenta oraz zawansowania choroby nowotworowej. Radykalna prostatektomia polega na usunięciu stercza wraz z pęcherzykami nasiennymi. Obecnie można te zabiegi wykonać metodami endoskopowymi klasycznie lub za pomocą robota chirurgicznego da Vinci. Inną metodą leczenia jest radykalna radioterapia. Radioterapię można podzielić na dwa rodzaje zewnętrzną i wewnętrzną (brachyterapię). Coraz częściej wykorzystywany jest robot radiochirurgiczny CyberKnife, który pozwala na dokładniejsze skierowanie wiązki promieniowania na nowotwór (tzw. radioterapia stereotaktyczna). W pracy autorka dokonuje przeglądu metod wykorzystujących roboty medyczne do leczenia raka gruczołu krokowego stosując metodologię nauk o zdrowiu.

EN

Prostate cancer is the second leading cause of death among men (National Cancer Registry). The choice of the treatment method is closely related to the patient's health condition and cancer type. Radical prostatectomy involves removal of the prostate including seminal vesicles. Currently, these procedures can be performed with endoscopic methods either classically or with the help of a da Vinci surgical robot. Another method of treatment is radical radiotherapy. Radiotherapy can be divided into two external and internal types (brachytherapy). The CyberKnife radiosurgical robot is being used more and more frequently, which allows for a more accurate positioning of the radiation beam (stereotactic radiotherapy). In the work, the author reviews the application of robotic methods to treat prostate cancer using the methodology of health sciences.

13

Analiza kształtu struktur anatomicznych jamy brzusznej dla potrzeb radioterapii nowotworu prostaty

Skalski A., Łągwa J., Kędzierawski P., Kukołowicz P.

Pomiary Automatyka Kontrola

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2013

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R. 59, nr 3

254--257

PL

W artykule przedstawiono algorytmy opisu kształtu, które mogą zostać wykorzystane do budowy wiedzy a priori, o którą można wzbogacić metody segmentacji danych medycznych. Opisana metodologia została wykorzystana do analizy kształtu struktur anatomicznych okolicy miednicy. Przeprowadzona analiza pozwoliła sprawdzić zmienność geometrii struktur anatomicznych istotnych z punktu widzenia radioterapii nowotworu prostaty, Zmienność kształtu organów oceniono zarówno: pomiędzy osobami w populacji chorych z nowotworem gruczołu krokowego jak i zmienność tych kształtów podczas procesu radioterapeutycznego u pacjenta.

EN

Prostate cancer is one of most frequently diagnosed cancer diseases among men population, especially in Europe and the USA. The number of fatal cases is also significant. It leads to many attempts to improve processes of the cancer diagnosis and therapy. One of most promising methods of treatment is radiation therapy. However, its proper planning requires contouring of every important structure on every slice obtained from the imaging equipment (in example a CT scanner), which is time-consuming for medical staff. To solve this problem, many efforts are made to construct algorithms of automatic segmentation of organs in 3D data. To provide the expected efficiency of such methods, a base of a priori knowledge about organs to be delineated is desired. In this paper we present shape description algorithms which could be used to collect the a priori knowledge, potentially able to improve the medical data segmentation methods. The described methodology was used in shape analysis of pelvic region structures, important for planning the prostate cancer radiation therapy, which included: GTV (Gross Tumor Volume), rectum, bladder and femoral heads. In this paper 5 different algorithms are presented. The first proposed method describes the shape of the analyzed organ with parameters (semi-axis lengths) of minimum-volume ellipsoid circumscribed on the structure. The other algorithms provide the information about the shape of the analyzedstructure as a distribution of chosen geometric quantity values (such as distance) between the groups of points randomly selected on its surface. The proposed algorithms were tested on the organ models reconstructed from the structures contoured on the images obtained from CT. As a result of the performed analysis, geometrical variability of the considered structures were specified. Variability of shapes of the analyzed organs was examined for the patients from the population group of men with diagnosed prostate cancer as well as for the single patient cases during radiation therapy.

14

Nocna praca zmianowa jako czynnik ryzyka kancerogenezy

Kawalec A., Pawlas K.

Bezpieczeństwo Pracy : nauka i praktyka

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2013

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nr 8

13-17

PL

Organizacja czasu pracy coraz częściej obejmuje pracę w systemie zmianowym, co wpływa na zdrowie pracowników. Artykuł porusza ostatnie doniesienia na temat wpływu pracy zmianowej na ryzyko kancerogenezy. Podano różne definicje pracy zmianowej, a także pokrótce przedstawiono skalę problemu. Zaprezentowano najnowsze wyniki badań dotyczących związku ryzyka raka piersi, endometrium, prostaty i jelita grubego z pracą zmianową. Przedstawiono stanowisko Międzynarodowej Agencji Badań nad Rakiem IARC (International Agency for Research on Cancer), która uznała pracę zmianową powodująca zaburzenia rytmu okołodobowego za prawdopodobny czynnik kancerogenny, zaliczając ją do grupy 2A. Pomimo wystarczających dowodów na wpływ kancerogenny światła w czasie biologicznej nocy na zwierzęta eksperymentalne, wciąż istnieją ograniczone dowody na kancerogenność pracy zmianowej, w tym pracy nocnej dla ludzi. Wskazano kierunki dalszych badań oraz konieczność opracowania profilaktyki.

EN

Nowadays organisation of work time often involves shiftwork , which affects workers’ health. This article analyses recent reports-on the influence of shiftwork on the risk of carcinogenesis. It presents various definitions of shiftwork and the scale of the problem. It also discusses the latest research on the association between risk of breast, endometrial, prostate and colon cancer, and shiftwork. According to the position of the International Agency for Research on Cancer IARC, shiftwork that involves night work resulting in disturbance in the circadian rhythm is a potential carcinogenic factor class 2A. Despite the sufficient evidence coming from experimental research performed on animals for. the cancerogenicity of light during work at night, there is still limited evidence for the cancerogenicity of shiftwork at night performed by humans. We conclude that further research should focus on preventive strategies.

15

Adaptacyjne metody napromieniania pacjentów z nowotworem gruczołu krokowego

Kukołowicz P., Piziorska M.

Inżynier i Fizyk Medyczny

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2012

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Vol. 1, nr 1

17--22

PL

Nowotwór gruczołu krokowego (NGK) jest najczęściej występującym nowotworem u mężczyzn [1]. Wybór metody leczenia jest uzależniony od stopnia zaawansowania choroby nowotworowej, wieku chorego, współistniejących chorób i często od preferencji pacjenta [2]. W leczeniu radykalnym miejscowo zaawansowanego NGK stosuje się leczenie chirurgiczne lub leczenie napromienianiem. Obecnie brakuje dowodów rozstrzygających, która metoda przynosi lepsze wyniki.

EN

The prostate cancer (PC) is the most frequent male neoplasm [1]. The selection of therapeutic method is dependent on the progression of neoplastic disease, age, coexisting ailments and the preferences [2]. In the PC radical treatment, the surgical methods, as well as the irradiation are applied. At present, there are no decisive evidence, which method reveals to be better.

16

The influence of xenobiotics and environmental selection upon carcinogenic changes in human male reproductive system

Dróżdż J. M., Kamiński P., Bombolewska K.

Environmental Biotechnology

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2012

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Vol. 8, No. 2

77--80

EN

This review is a compilation of the recent reports on a role of environmental factors on a cancer development in male reproductive system. We have analyzed studies of environmental pollution and disorders of mechanisms responsible for defense against impact of xenobiotics upon the prostate cancer and testicular cancer occurrence. Moreover, we have focused on the polymorphisms of selected genes, which in excessive exposure to environmental stress factors might exacerbate disorders of an organism defense against impact of xenobiotics. It is well known that environmental factors such as toxic heavy metals pollution, impact of xenobiotics or environmental stress have an influence on the human reproductive system. There were many studies suggesting an association between these factors and the prostate or testicular cancer development, but still there are no unambiguous conclusive results. Studies of specific changes in markers, which occur in response to various environmental stressors are also very interesting. They focus on the influence of chemical elements (Cd, Zn, Ca) destabilization and heavy metals pollution over an organism and the environment. Antioxidant enzymatic mechanisms in conditions of anthropogenic impact and the influence of polymorphisms in genes involved in genetic material damage repair under stress conditions have also been studied. The aim of this review was to combine essential important data suggesting possible role of environmental factors in the initiation and development of carcinogenic processes in male reproductive system based on prostate cancer and testicular cancer cases. On this basis the current needs and research directions could be delineated.

17

New approach to prostate diagnosis - perfusion CT images analysis using "life belt" method

Śmietański J., Tadeusiewicz R.

Bio-Algorithms and Med-Systems

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2012

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Vol. 8, no. 1

145--158

EN

The most important task that could improve the efficacy of managing the prostate cancer (PCa) is to develop the technique which will be able to detect an existing PCa even in cases when currently used methods are insufficient. It is supposed that the perfusion computed tomography technology (p-CT) can improve the diagnosis of early PCa. Unfortunately, the perfusion prostate images are very difficult to analyze especially for doctors who are not enough experienced with such a kind of images. Therefore there is a need to find a computational method which could help the doctors to make the decision whether the prostate cancer exists or not and (if the results are positive) to correctly point out the cancerous region. In research which results are presented in the paper we analyzed a great number of prostate images derived from over 50 patients with proven or suspected PCa. We propose the new method, named “life-belt” which has significant potential for identifying cancerous regions.

18

Leakage test evaluation used for qualification of iodine-125 seeds sealing

Feher A., Rostelato M. E. C. M., Zeituni C. A., Calvo W. A. P., Somessari S. L., Moura J. A., Moura E. S., Souza C. D., Rela P. R.

Nukleonika

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2011

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Vol. 56, No. 4

375-379

EN

Brachytherapy is one of the possible treatments with ionizing radiation available for prostate cancer, in which small seeds containing iodine-125 radioisotope are implanted directly into the prostate. The seed consists of a sealed titanium tube containing a central silver wire with adsorbed iodine-125. The tube sealing is made with titanium at the ends, using plasma arc-welding (PAW) or laser process. This sealing must be leakage-resistant and free of cracks, therefore avoiding iodine-125 to deposit in the silver wire to escape and spread into the human body. To ensure that this problem is not occurring, rigorous leakage tests in accordance with the standard ISO-9978 should be applied. The aim of this study is to determine, implement and evaluate the leakage test to be used in the iodine-125 seeds production, in order to qualify the sealing procedure. The standard ISO-9978 presents a list of tests to be carried out according to the type of source. The preferential methods for brachytherapy sources are soaking and helium. To assess the seeds leakage, the method of immersion test at room temperature was applied. The seeds are considered leakage-free if the detected activity does not exceed 185 Bq (5 nCi). An iodine standard was prepared and its value determined in a sodium iodide detector. A liquid scintillation counter was calibrated with the standard for seed leakage tests. Forty-eight seeds were plasma arc-welded for these tests.

19

Development of an automation system for iodine-125 brachytherapy seed encapsulated by Nd:YAG laser welding

Somessari S. L., Feher A., Sprenger F. E., Rostelato M. E. C. M., da Costa F. E., Calvo W. A. P.

Nukleonika

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2011

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Vol. 56, No. 4

369-374

EN

The aim of this work is to develop an automation system for iodine-125 radioactive seed production by Nd:YAG laser welding, which has been used successfully in low dose rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8 mm in diameter and 4.5 mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at Institute for Nuclear and Energy Research, Săo Paulo, Brazil (IPEN-CNEN/SP) imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources became a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a larger number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with good manufacturing practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing a programmable logic controller (PLC), a stepper motor, an Nd:YAG laser welding machine and a supervisory. The statistical repeatability of correctly encapsulated sealed sources with this automation system is greater than 95 per cent.

20

Discriminatory Power of Co-Occurrence Features in Perfusion CT Prostate Images

Śmietański J., Tadeusiewicz R.

Machine Graphics and Vision

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2010

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Vol. 19, No. 2

185-199

EN

This paper presents an algorithm used to improve the effectiveness of early prostate cancer (PCa)detection. The necessity for using such a computational method lies in the fact that although perfusion computed tomography (p-CT) is considered a good technique for the detection of early PCa, the p-CT prostate images are very difficult to interpret manually by radiologists. We hereby propose a methodology for computational analysis of p-CT prostate images based on textural coefficients derived from co-occurrence matrices and their 21 coefficients. The selection of only a few of the considered features ensures the necessary balance between matching set of already known images and new, not yet clear cases. The proposed algorithm for automatic differentiation of the healthy area of the image from the cancerous region was tested on a set of 59 prostate images. Although the results were not entirely satisfactory (86% correct recognitions), this method may be considered as the base for the development of a better algorithm.