Breast cancer normal tissue complication modelling and parameter uncertainties

ABSTRACT: External radiation treatment (ERT) is one of the treatment methods against breast cancer. As all therapies, radiation is linked with side effects. Utmost goal during the treatment with radiation is to maximize the benefit for the patient (efficacy of the treatment) while sparing other vital organs from radiation that could lead to organ’s toxicity. The assessment of the overall benefit of a radiation treatment can be modelled with the help of linear quadratic model. That model simulates the cell killing for a specific type of cell (each cell cancerous or healthy has different properties: radiosensitivity, proliferation) under a given radiation prescription and schema. With the help of modelling, oncologists and medical physicists can simulate and predict the outcome of a radiation treatment schema

Dosimetric Impact of the Positional Imaging Frequency for Hypofractionated Prostate Radiotherapy – A Voxel-by-Voxel Analysis

Background: To investigate deviations between planned and applied treatment doses for hypofractionated prostate radiotherapy and to quantify dosimetric accuracy in dependence of the image guidance frequency. Methods: Daily diagnostic in-room CTs were carried out in 10 patients in treatment position as image guidance for hypofractionated prostate radiotherapy. Fraction doses were mapped to the planning CTs and recalculated, and applied doses were accumulated voxel-wise using deformable registration. Non-daily imaging schedules were simulated by deriving position correction vectors from individual scans and used to rigidly register the following scans until the next repositioning before dose recalculation and accumulation. Planned and applied doses were compared regarding dose-volume indices and TCP and NTCP values in dependence of the imaging and repositioning frequency. Results: Daily image-guided repositioning was associated with only negligible deviations of analyzed dose-volume parameters and conformity/homogeneity indices for the prostate, bladder and rectum. Average CTV T did not significantly deviate from the plan values, and rectum NTCPs were highly comparable, while bladder NTCPs were reduced. For non-daily image-guided repositioning, there were significant deviations in the high-dose range from the planned values. Similarly, CTV dose conformity and homogeneity were reduced. While TCPs and rectal NTCPs did not significantly deteriorate for non-daily repositioning, bladder NTCPs appeared falsely diminished in dependence of the imaging frequency. Conclusion: Using voxel-by-voxel dose accumulation, we showed for the first time that daily image-guided repositioning resulted in only negligible dosimetric deviations for hypofractionated prostate radiotherapy. Regarding dosimetric aberrations for non-daily imaging, daily imaging is required to adequately deliver treatment

Evaluation of intensity modulated radiation therapy dose painting for localized prostate cancer using 68 Ga-HBED-CC PSMA-PET/CT: A planning study based on histopathology reference

AbstractPurposeTo demonstrate the feasibility and to evaluate the tumour control probability (TCP) and normal tissue complication probability (NTCP) of IMRT dose painting using 68Ga-HBED-CC PSMA PET/CT for target delineation in prostate cancer (PCa).Methods and materials10 patients had PSMA PET/CT scans prior to prostatectomy. GTV-PET was generated on the basis of an intraprostatic SUVmax of 30%. Two IMRT plans were generated for each patient: Plan77 which consisted of whole-prostate IMRT to 77Gy, and Plan95 which consisted of whole-prostate IMRT to 77Gy and a simultaneous integrated boost to the GTV-PET up to 95Gy (35 fractions). The feasibility of these plans was judged by their ability to adhere to the FLAME trial protocol. TCP-histo/-PET were calculated on co-registered histology (GTV-histo) and GTV-PET, respectively. NTCPs for rectum and bladder were calculated.ResultsAll plans reached prescription doses whilst adhering to dose constraints. In Plan77 and Plan95 mean doses in GTV-histo were 75.8±0.3Gy and 96.9±1Gy, respectively. Average TCP-histo values for Plan77 and Plan95 were 70% (range: 15–97%), and 96% (range: 78–100%, p77 and Plan95 were 55% (range: 27–82%), and 100% (range: 99–100%, p95 (p=0.25). There were no significant differences in rectal (p=0.563) and bladder (p=0.3) NTCPs.ConclusionsIMRT dose painting using PSMA PET/CT was technically feasible and resulted in significantly higher TCPs without higher NTCPs

Predictors of radiation-induced late rectal toxicity in prostate cancer treatment: a volumetric and dosimetric analysis

IntroductionProstate cancer (PCa) is a prevalent malignancy in European men, often treated with radiotherapy (RT) for localized disease. While modern RT achieves high success rates, concerns about late gastrointestinal (GI) toxicities persist. This retrospective study aims to identify predictors for late GI toxicities following definitive conventionally fractionated external beam RT (EBRT) for PCa, specifically exploring the dose to the rectal wall.Materials and methodsA cohort of 96 intermediate- to high-risk PCa patients underwent EBRT between 2008 and 2016. Rectum and rectum wall contours were delineated, and 3D dose matrices were extracted. Volumetric and dosimetric indices were computed, and statistical analyses were performed to identify predictors using the Mann–Whitney U-rank test, logistic regression, and recursive feature elimination.ResultsIn our cohort, 15 out of 96 patients experienced grade II late proctitis. Our analysis reveals distinct optimal predictors for rectum and rectum wall (RW) structures varying with α/β values (3.0 and 2.3 Gy) across prescribed doses of 68 to 76 Gy. Despite variability, RW predictors demonstrate greater consistency, notably V68Gy[%] to V74Gy[%] for α/β 3.0 Gy, and V68Gy[%] to V70Gy[%] for α/β 2.3 Gy. The model with α/β 2.3 Gy, featuring RW volume receiving 70 Gy (V70Gy[%]), stands out with a BIC value of 62.92, indicating its superior predictive effectiveness. Finally, focusing solely on the rectum structure, the V74Gy[%] emerges the best predictor for α/β 3.0 Gy, with a BIC value of 66.73.ConclusionThis investigation highlights the critical role of V70Gy[%] in the rectum wall as a robust predictor for grade II late gastrointestinal (GI) toxicity following external beam radiation therapy (EBRT) for prostate cancer (PCa). Furthermore, our findings suggest that focusing on the rectum wall specifically, rather than the entire rectum, may offer improved accuracy in assessing proctitis development. A V70Gy (in EQD2 with α/β 2.3 Gy) of ≤5% and if possible ≤1% for the rectal wall should be achieved to minimize the risk of late grade II proctitis

Image and Medical Data Communication Protocols for Telemedicine and Teleradiology

Telemedicine is currently being used to bridge the physical distance between patients in remote areas and medical specialists around the world. Distributed client-server applications have become very popular with the explosive growth of the Internet. These distributed applications provide an inexpensive and fast way to access medical information and also provide good accessibility and availability of medical service. Telemedicine applications are a client/server applications where medical and patient information is stored in a server and the information is made accessible to doctors and medical personnel at a distant site. In addition, depending on the type and the needs of the medical application different type of communication protocols and medical devices are utilized making interoperability and communication over different communication channels quite difficult. In my dissertation I analyzed first a range of telemedicine systems already used and I concluded that telemedicine systems can be categorized according to on three different features (layers): • Transportation protocol layer • Medical devices layer • Application layer The outcome of the analysis was that on the application layer, there exists a wide variety of different telemedical applications, each one supporting a special and focused medical application case. Thus, on the application layer a heterogeneous environment of medical use cases exists and it not possible to homogenize due to the particularities of each medical situation. Regarding the device layer, a plurality of different medical devices is used for each medical application supporting different functionality. As an example, one uses ECG devices for monitoring heard activity, blood pressure devices to measure the diastolic and systolic arterial pressure, ultrasound, CT, MRI devices for medical imaging analyzing physiological structures and so on. Nevertheless, although the individual devices will have to remain separate, I propose here an interfacing scheme enabling connection of the various devices to a unique data interface, enabling their individual data to be transferred and handled in a unique, transparent way. By this I integrated a wide variety of medical devices offering flexible solutions covering large number of home care, emergency and radiology applications. On the transportation layer I concluded that a number of various telecommunication protocols are utilized and miscellaneous types of data types and data sizes are to be exchanged, depending on their application. In addition, I concluded that all the communication protocols applied today show common problems emerging from firewalls and network address translation servers. I also concluded that the applied communication protocols do not support presence awareness of the users. Based on the aforementioned observations, I propose an instant messaging protocol able to homogenize the communication and transportation layer and support any data type and any data size while solving all of the existing problems at once. In this way I unified the various protocols, replacing them by only one, at the same time overcoming common problems arising from firewalls, NATs and mobility of the users. Traumastation shows exemplarily the correctness of my approach and demonstrates how several different medical devices can be integrated on one single case and support a wide variety of applications utilising thereby one single data transportation protocol

Home: a modular telemedicine system

Abstract: In that paper we will describe a system for remotely monitoring of patients at home from the doctors at the hospital. In general, the @Home [AtH02] system can measure, collect, analyze and record health care data at a patient’s home and then subsequently send these data to the hospital using the global system for mobile communications (GSM) or PSTN telephone line. The paper is organized as follows: I

T@HIS: A Satellite Based Telemedicine Network for Imaging Teleconsultations

T@His is an ESA (European Space Agency) project for the deployment of a telemedical network connecting physicians and hospitals over a new-generation satellite network based on the AmerHis payload on the Hispasat Amazonas satellite. The consortium is formed by Thales Alenia Space España (Spain), Fraunhofer IGD (Germany) and CETA (Center of Excellence in Advanced Technology of Rio Grande do Sul in Brazil). The project objectives are to extend current medical network connecting isolated areas in Amazon over satellite communication. The project involved three remote sites in isolated areas and one site in urban area. Intotal four satellite terminals have been deployed at Porto Alegre (referral hospital in southern Brazil), Breves, Portel and Gurupá. All three spokes are located in Pará state, in northern Brazil. T@His é um projeto da ESA (Agência Espacial Européia) para o desenvolvimento de uma rede telemédica conectando especialistas e hospitais com uma nova geração de redes de satélites baseado no AmerHis com carga sobre o satélite Hispasat Amazonas. O consórcio é formado pela Thales Alenia Space España (Espanha), Fraunhofer IGD (Alemanha) e CETA (Centro Excelência em Tecnologias Avançadas do Rio Grande do Sul, Brasil). O objetivo do projeto é aumentar a rede médica atual conectando as áreas do Amazonas através de uma rede de comunicação por satélite. O projeto envolveu três locais remotos em áreas isoladas e um local na zona urbana. No total, quatro terminais de satélite foram implantados em Porto Alegre (hospital de referência no sul do Brasil), Breves, Portel e Gurupá. Os três estão localizados no Estado do Pará, no norte do Brasil

The use of deep learning in interventional radiotherapy (brachytherapy): A review with a focus on open source and open data

Deep learning advanced to one of the most important technologies in almost all medical fields. Especially in areas, related to medical imaging it plays a big role. However, in interventional radiotherapy (brachytherapy) deep learning is still in an early phase. In this review, first, we investigated and scrutinised the role of deep learning in all processes of interventional radiotherapy and directly related fields. Additionally, we summarised the most recent developments. For better understanding, we provide explanations of key terms and approaches to solving common deep learning problems. To reproduce results of deep learning algorithms both source code and training data must be available. Therefore, a second focus of this work is on the analysis of the availability of open source, open data and open models. In our analysis, we were able to show that deep learning plays already a major role in some areas of interventional radiotherapy, but is still hardly present in others. Nevertheless, its impact is increasing with the years, partly self-propelled but also influenced by closely related fields. Open source, data and models are growing in number but are still scarce and unevenly distributed among different research groups. The reluctance in publishing code, data and models limits reproducibility and restricts evaluation to mono-institutional datasets. The conclusion of our analysis is that deep learning can positively change the workflow of interventional radiotherapy but there is still room for improvements when it comes to reproducible results and standardised evaluation methods

A Portable Medical Unit for Medical Imaging Telecollaboration

In this paper, we are going to introduce a multimodal portable medical device for both medical imaging tele-collaboration and monitoring of vital parameters. The introduced portable unit offers diversity of medical devices and is in position to acquire ultrasound images, ECG 12 leads, and blood pressure and be able to measure oxygen level in the blood. In addition, the portable unit is equipped with all available telecommunication gateways (e.g. GSM, UMTS, ISDN, DSL, Satellite) providing a great communication convenience to the physicians utilizing XMMP instant messaging protocols

A portable medical unit for medical imaging telecollaboration

In this paper, we are going to introduce a multimodal portable medical device for both medical imaging tele-collaboration and monitoring of vital parameters. The introduced portable unit offers diversity of medical devices and is in position to acquire ultrasound images, ECG 12 leads, and blood pressure and be able to measure oxygen level in the blood. In addition, the portable unit is equipped with all available telecommunication gateways (e.g. GSM, UMTS, ISDN, DSL, Satellite) providing a great communication convenience to the physicians utilizing XMMP instant messaging protocols