Hybrid Gamma Camera in Breast Surgery

This is a single centre prospective, non-randomised and non-blinded research project using the camera in the operating theatre in addition to the standard gamma surgical probe for assessing lymph node involvement in breast cancer patients undergoing surgery for their disease. The duration of the study is 1 year. The purpose of the trial will be to determine if the camera can be used for the localisation of sentinel lymph nodes during the SLNB procedure and to compare detection rates of sentinel lymph node(s) with the standard method using the gamma probe. Study Plan: This study will not alter the standard SLNB procedures provided by the healthcare provider. The camera will be used to acquire images in the axillary and parasternal regions as additional steps to the standard SLNB procedures. No invasive actions are performed. Images obtained using the camera in this study will include gamma, optical and fused gamma/optical images in each acquisition. In additional to the intraoperative imaging study using the camera system, a subjective assessment by questionnaire will be carried out amongst the surgeons to obtain their feedback. Statistics: For the quantitative analysis, the distribution of continuous variables will be summarised using mean and standard deviation (if normally distributed) or median and range (if not normally distributed); distribution of categorical variables will be summarised by presenting the number and percentages that falling into each categories. Missing data will be recorded. SPSS will be used to manage the data. The detection rate of both detection methods (camera versus standard techniques) will be tabulated as binary data (yes/no). Validity analysis will be computed for sensitivity, specificity, positive predictive value and negative predictive value. Also Kappa (categorical data) method will be used to examine the agreement between two methods. Good agreement will be claimed if the value of kappa between 0.81 and 1.00. Sample size: The calculated sample size is 53 participants. It has been calculated using nQuery Advisor® 6.0 with the goal to make conclusion using agreement. The sample size has the 80% power to pick up ҡ1 = 0.410 or greater.