Development of Photoacoustic and Ultrasound Transrectal Probe for Prostate Biopsy

描述(申请人提供)：前列腺癌的适应症主要是前列腺特异性抗原(PSA)升高或直肠指诊(DRE)异常，以及及时经直肠超声(TRUS)引导的前列腺活检以确定诊断。通常，有一些肿瘤在TRUS上看不到(等回声)。此外，在PSA筛查人群中，由于假阳性结果，TRUS的准确率仅为52%，对于前列腺癌的检测和定位并不可靠，而前列腺癌目前是唯一的选择 活组织检查。其目的是排除PSA假阳性患者中的前列腺癌，并定位癌症以进行有针对性的活检。为了鉴别前列腺癌和良性前列腺组织，我们提出了一种基于多光谱光声成像(PA)的手持式经直肠成像探头，可以检测体内脱氧血红蛋白(DHb)、氧合血红蛋白(HBO2)、脂肪和水的相对浓度的变化。我们项目的具体目标包括：目标1：开发一种双模式系统，将超声(US)成像整合到我们现有的体外PA成像探头中，以生成共同配准的双模式图像。目的：设计并制作一种活体经直肠双模式(US+PA)成像探头，该探头能够产生适用于前列腺活检的联合配准图像。目的3：对组织等效体模进行PA和US成像实验，以验证体内双模成像探头的性能并确定其质量指标。该项目的最终目标是开发一种成像方式，可以清楚地区分PSA阳性患者的前列腺癌和良性前列腺组织。这也将有助于识别和监测不需要进一步治疗的患者，并有助于减少由于TRUS活检针的癌症靶向不佳而导致的假阴性结果。这种探头可能有助于降低TRUS活检率或完全消除它(如果侵袭性癌症和惰性癌症可以通过多光谱光声成像来识别)。由于PA成像的功能性质，建议的探针可能是评估前列腺癌预后、药物反应和检测肿瘤复发的有用工具。

DESCRIPTION (provided by applicant): Indications of prostate cancer are predominantly an elevated prostate specific antigen (PSA) test or abnormal digital rectal exam (DRE), and prompt transrectal ultrasound (TRUS) guided biopsy of the prostate for definitive diagnosis. Often, there are cancers that are not visible (iso- echoic) on TRUS. Furthermore, in PSA screened populations, the accuracy of TRUS is only 52% due to false-positive results and is not reliable for the detection and localization of prostate cancer which is currently the only choice to perform biopsies. The aim is to exclude prostate cancer in patients with false positive PSA results and localize the cancer for targeted biopsies. To differentiate cancerous from benign prostate tissue, we propose to develop a handheld transrectal imaging probe based on multispectral photoacoustic (PA) imaging that can detect changes in relative concentrations of deoxyhemoglobin (dHb), oxyhemoglobin (HbO2), lipid and water in vivo. Specific Aims of our project include: Aim 1: To develop a dual modality system that will incorporate ultrasound (US) imaging into our existing ex-vivo PA imaging probe to generate co-registered dual modality images. Aim 2: To design and fabricate an in-vivo transrectal dual mode (US + PA) imaging probe capable of generating co-registered images suitable for prostate biopsy. Aim 3: Perform PA and US imaging experiments on the tissue equivalent phantoms to validate the performance and determine the quality metrics of the in-vivo dual mode imaging probe. The ultimate goal of this project is to develop an imaging modality that can clearly differentiate cancerous from benign prostate tissue in patients with positive PSA results. This will also help identify and monitor patients who need no further treatment, as well as aid in reducing false negative results due to poor cancer targeting of TRUS biopsy needles. This probe may help to reduce the TRUS biopsy rate or eliminate it altogether (if aggressive versus indolent cancers can be identified by multispectral photoacoustic imaging). Due to the functional nature of PA imaging, it is possible that the proposed probe may be a useful tool to evaluate prostate tumor prognosis, response to drugs, and detection of tumor recurrence.