title: In vivo visualization of prostate brachytherapy seeds with photoacoustic imaging.
abstract: We conducted a canine study to investigate the in vivo feasibility of photoacoustic imaging for intraoperative updates to brachytherapy treatment plans. A fiber coupled to a 1064-nm Nd:YAG laser was inserted into high-dose-rate brachytherapy needles, which diffused light spherically. These needles were inserted through the perineum into the prostate for interstitial light delivery and the resulting acoustic waves were detected with a transrectal ultrasound probe. Postoperative computed tomography images and ex vivo photoacoustic images confirmed seed locations. Limitations with insufficient light delivery were mitigated with short-lag spatial coherence (SLSC) beamforming, providing a 10-20 dB contrast improvement over delay-and-sum (DAS) beamforming for pulse energies ranging from 6.8 to 10.5 mJ with a fiber-seed distance as large as 9.5 mm. For the same distance and the same range of energy densities, signal-to-noise ratios (SNRs) were similar while the contrast-to-noise ratio (CNR) was higher in SLSC compared to DAS images. Challenges included visualization of signals associated with the interstitial fiber tip and acoustic reverberations between seeds separated by ≤ 2 mm. Results provide insights into the potential for clinical translation to humans.
authors.affiliation: Johns Hopkins University, CISST Engineering Research Center, Baltimore, Maryland 21218, United States.
authors.forename: Muyinatu A
authors.initials: MA
authors.lastname: Lediju Bell
authors.affiliation: Johns Hopkins University, Department of Biomedical Engineering, Baltimore, Maryland 21218, United StatescJohns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland 21218, United States.
authors.forename: Nathanael P
authors.initials: NP
authors.lastname: Kuo
authors.affiliation: Johns Hopkins University School of Medicine, Department of Radiation Oncology and Molecular Radiation Sciences, Baltimore, Maryland 21205, United States.
authors.forename: Danny Y
authors.initials: DY
authors.lastname: Song
authors.affiliation: Johns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland 21218, United States.
authors.forename: Jin U
authors.initials: JU
authors.lastname: Kang
authors.affiliation: Johns Hopkins University, CISST Engineering Research Center, Baltimore, Maryland 21218, United StatescJohns Hopkins University, Department of Electrical and Computer Engineering, Baltimore, Maryland 21218, United StateseJohns Hopkins University, School of.
authors.forename: Emad M
authors.initials: EM
authors.lastname: Boctor
mesh_terms: D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D004285:Dogs; D008297:Male; D061088:Photoacoustic Techniques / Q000379:methods*; D011467:Prostate / Q000033:anatomy & histology*; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided; D015203:Reproducibility of Results