Investigation of the logfiles of freehand SPECT acquisitions for usage characteristics and surgical phase determination

Bachelor IDP by: Richard Voigt
Advisor: Prof. Nassir Navab
Supervision by: Aslı Okur
Due date: 2013/11/15

Abstract

In Klinikum rechts der Isar, TU München, there is currently a clinical study started called "SLN3D", where the nuclear medicine, gynecology departments from the medical side and the CAMP chair from the technical side are involved in. In this study, 150 patients are planned to be recruited, where the Freehand SPECT (fhSPECT) system developed by the CAMP chair and the company SurgicEye GmbH is to be used intra-operatively in sentinel lypmh node biopsy (SLNB) procedures of breast cancer patients. Until now, more than 50 patients are recruited for the study and underwent a SLNB with fhSPECT already.

For evaluation of intra-operative imaging devices, an extensible and flexible data gathering and evaluation framework called ORUse has been developed in the CAMP chair. The first device modeled in this framework is the Freehand SPECT system, which is mentioned above. For each of the acquisitions the fhSPECT system automatically saves all available information into text files, such as tracking, user interaction or activity logs. Even though these files include almost all the information about how the users used the system, they are hard to interpret by the end users due to their sizes, the redundancy in the data and synchronisation via timestamps. Until now, only the automatic output of the Freehand SPECT system is included in the ORUse, with no filtering or analysis of the huge amount of the log files. Furthermore, proper analysis of these log files can be useful to approximate the phases of the surgical workflow and the time estimation. Also due to the freehand nature of the device different scan patterns and/or speeds can be identified and investigated for influence in resulting images.

The goal of this interdisciplinary project is to develop an application, which will be used later for analysis of the medical data for usage characteristics and surgical workflow durations by the study investigators. The programming environment will be either C++ or C# and Visual Studio. This tool then will be used to upload and integrate the results inside the ORUse framework.

Project Outline

1. Introduction

• Getting familiar with the medical data
• Getting familiar with C++ or C#, .NET and Visual Studio
• Analysis of the provided log files
• Attending some surgeries in Klinikum rechts der Isar with Freehand SPECT system for understanding the surgical workflow

2. Implementation

• Parsing and synchronization of the log files
• Calculation of the time from timestamps to UTC using the base reference time
• Calculation of the duration of device workflow stages
• Approximation of the duration of surgical workflow stages based on device workflow durations
• Calculation of scan and reconstruction duration
• Calculation of scan characteristics (speed, covered area, tracking problems)
• Identification of tracking problems by analysis of the patient target position changes in data
• Identification of changes in UI components in visualization view (view mode changes, threshold parameter changes)
• GUI for user interaction and manual input
• Automatic report generation for usage characteristics and further statistics
• Upload-Interface to ORUse Framework and implementation of dedicated database tables and a dedicated parser on the server side (optional)

3. Analysis and Evaluation

• Testing the tool with experimental data
• Analysis of available real patient data using the developed tool
• Statistics calculation and determination of user-dependent characteristics for different users or user groups

4. Documentation and Presentation