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Photoacoustic imaging (PAI) of biological tissue has been a fast developing biomedical multi-wave imaging modality, after its introduction in the mid90s. PAI couples laser excitation to acoustic detection. Especially, in recent years its significant advantages in onco-surgery has attracted much attention due to its ability to detect malignant tissues. Monitoring cancer angiogenesis, assessment of blood oxygen saturation, functional brain imaging, evaluation of cortical blood volume, detection of skin/conjunctival melanoma depth, assessment of met-hemoglobin, investigating tumor hypoxia andcancer lymph node metastases are some of its promising applications. Moreover, as a real-time monitoring strategy, PAI allows intraoperative imaging of micro-metastases and residual islands in onco-surgery. Herein, we provide a brief introduction to biophysics and fundamentals of PAI, potential novel endogenous and exogenous contrast agents, and novel techniques to develop engineered and targeted contrast agents with theranostic applications. We also summarize the clinical trial pipelines for PAI. Furthermore, we discuss the potential obstacles and limitation of PAI theranostic agents for further clinical applications and strategies to overcome these hurdles.

Background: Colorectal cancers are the third common malignancies after lung and breast neoplasms. Some contributing factors for pathological complete response (pCR) to neoadjuvant therapy of rectal cancer have been defined. Despite various studies in this era, there are few studies on the location of tumors. Objectives: Regarding the high prevalence of colorectal cancer in Iran and the importance of neoadjuvant chemoradiation for survival and morbidity, this study was carried out to determine the association between pathologic complete response and tumor location in patients with rectal cancer after neoadjuvant chemoradiotherapy. Methods: In this prospective cohort, 100 cases with rectal adenocarcinoma from 2017 to 2019 were enrolled. Distance between anal verge and tumor was measured by clinical examination, colonoscopy, endo-sonography, and MRI. Tumors were defined as distal (less than 5 cm from the anal verge) and none distal (more than 5 cm from the anal verge). Another subdivision was inferior (0 - 4.99 cm), middle (5 - 9.99 cm), and superior (10 - 15 cm). The pathological response was compared across the groups. Results: In this study, the pCR was seen in 30%. In univariate analysis body mass index (BMI), grade, N-stage, and distance from anal verge were related to pCR. In cases with BMI over 25 kg/m2 and in tumors with low to medium grade N0/N1, and distance less than 5 cm from the anal verge (low lying tumors) the pCR to neoadjuvant treatment was higher. In multivariate analysis tumor grade, N stage, and distance from anal verge were still related to pCR. Conclusions: According to the obtained results in this study, there may be some association between rectal tumor location and pathologic complete response.

Introduction: Methotrexate (MTX) is the most generally administered antimetabolite in pediatric cancers. Renal excretion is the major route of elimination of MTX. However, renal toxicity and delayed MTX elimination is a particular concern and direct serum MTX concentration is a gold standard for renal toxicity monitoring. However, checking plasma MTX concentrations in most oncology institutions is not always possible especially in less developed countries. Objectives: The purpose of this study was to further assess the renal function after administration of high-dose MTX by parameters such as serum creatinine and Cr clearance rate. Patients and Methods: This is a cross-sectional descriptive analytic study. The study was conducted on children with acute lymphoblastic leukemia, non-Hodgkin lymphoma and osteosarcoma receiving high doses MTX. Patients’ age was ranged from 5 to 16 years. Serum MTX concentration and serum Cr were measured at 24, 48 and 96 hours after receiving MTX and then Cr clearance calculated based on available formulas. All the statistical analyses were done by SPSS 20.0 statistical software Results: This study was performed on 4 patients with osteosarcoma, 3 patients with leukemia and one patient with lymphoma. MTX concentration reduced significantly during 96 hours (PConclusion: Our findings indicated that serum Cr and Cr clearance can be used to estimate the average of serum MTX concentrations.