Intraoperative Needle Tip Tracking with an Integrated Fibre-Optic Ultrasound Sensor.

Ultrasound is an essential tool for guidance of many minimally-invasive surgical and interventional procedures, where accurate placement of the interventional device is critical to avoid adverse events. Needle insertion procedures for anaesthesia, fetal medicine and tumour biopsy are commonly ultrasound-guided, and misplacement of the needle may lead to complications such as nerve damage, organ injury or pregnancy loss. Clear visibility of the needle tip is therefore critical, but visibility is often precluded by tissue heterogeneities or specular reflections from the needle shaft. This paper presents the in vitro and ex vivo accuracy of a new, real-time, ultrasound needle tip tracking system for guidance of fetal interventions. A fibre-optic, Fabry-Pérot interferometer hydrophone is integrated into an intraoperative needle and used to localise the needle tip within a handheld ultrasound field. While previous, related work has been based on research ultrasound systems with bespoke transmission sequences, the new system-developed under the ISO 13485 Medical Devices quality standard-operates as an adjunct to a commercial ultrasound imaging system and therefore provides the image quality expected in the clinic, superimposing a cross-hair onto the ultrasound image at the needle tip position. Tracking accuracy was determined by translating the needle tip to 356 known positions in the ultrasound field of view in a tank of water, and by comparison to manual labelling of the the position of the needle in B-mode US images during an insertion into an ex vivo phantom. In water, the mean distance between tracked and true positions was 0.7 ± 0.4 mm with a mean repeatability of 0.3 ± 0.2 mm. In the tissue phantom, the mean distance between tracked and labelled positions was 1.1 ± 0.7 mm. Tracking performance was found to be independent of needle angle. The study demonstrates the performance and clinical compatibility of ultrasound needle tracking, an essential step towards a first-in-human study.

The heart of the matter: secretory pheochromocytoma presenting as recurrent biventricular heart failure (Takotsubo cardiomyopathy).

Takotsubo's syndrome (TS) is an acute, transient cardiomyopathy occurring secondary to physical or emotional stressors through catecholamine excess. Secretory pheochromocytomas have been previously implicated in cases of TS (PTS), however, often present atypically, are associated with reoccurrence, and have higher rates of complications. We describe the case of a 70-year-old female who presented central chest pain, hypotension and electrocardiogram changes on a background of a 6-month prior episode of resolved Takotsubo's with unknown cause. After progressing to cardiogenic shock with biventricular failure, computerized tomography coronary aortogram revealed an incidental adrenal mass, later proven to be a secretory pheochromocytoma on biochemistry and subsequent histology. PTS has been associated with recurrence and rarely presents as cardiogenic shock. This case highlights the complexity of TS presentations and complications and the diagnostic delays that may occur in PTS.

A pancreatic mass and extreme elevation of CA 19-9: a benign masquerade of cholangiocarcinoma.

Carbohydrate antigen 19-9 (CA 19-9) is a specific tumour marker for pancreato-biliary malignancy. Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition in which IgG4 deposits infiltrate various organs, including the biliary tract manifesting IgG4 sclerosing cholangitis and pseudotumours. An 83-year-old woman presented with severe obstructive jaundice, weight loss and an extreme elevation of CA 19-9 level of 3295 kU/L. Magnetic resonance cholangiopancreatography (MRCP) revealed a pancreatic mass amputating the biliary tree. Liver function tests revealed a cholestatic pattern and severe hyperbilirubinaemia (289umol/L). IgG4 level was found to be high at 7.97 g/L. After treatment with high-dose corticosteroids, repeat MRCP 2 months later revealed disappearance of the pancreatic mass. There was also normalization of the bilirubin and a dramatic decrease of CA 19-9. This case reports the highest published benign elevation of Ca19.9 level in the setting of IgG4 disease. Differentiation between cholangiocarcinoma and IgG4-RD is important, as the treatment is vastly different.

Ultrasonic Needle Tracking with Dynamic Electronic Focusing.

Accurate identification of the needle tip is a key challenge with ultrasound-guided percutaneous interventions in regional anaesthesia, foetal surgery and cardiovascular medicine. In this study, we developed an ultrasonic needle tracking system in which the measured needle tip location was used to set the electronic focus of the external ultrasound imaging probe. In this system, needle tip tracking was enabled with a fibre-optic ultrasound sensor that was integrated into a needle stylet, and the A-lines recorded by the sensor were processed to generate tracking images of the needle tip. The needle tip position was estimated from the tracking images. The dependency of the tracking image on the electronic focal depth of the external ultrasound imaging probe was studied in a water bath and with needle insertions into a clinical training phantom. The variability in the estimated tracked position of the needle tip, with the needle tip at fixed depths in the imaging plane across a depth range from 0.5 to 7.5 cm, was studied. When the electronic focus was fixed, the variability of tracked position was found to increase with distance from that focus. The variability with the fixed focus was found to depend on the the relative distance between the needle tip and focal depth. It was found that with dynamic focusing, the maximum variability of tracked position was below 0.31 mm, as compared with 3.97 mm for a fixed focus.

Precision-Microfabricated Fiber-Optic Probe for Intravascular Pressure and Temperature Sensing.

Small form-factor sensors are widely used in minimally invasive intravascular diagnostic procedures. Manufacturing complexities associated with miniaturizing current fiber-optic probes, particularly for multi-parameter sensing, severely constrain their adoption outside of niche fields. It is especially challenging to rapidly prototype and iterate upon sensor designs to optimize performance for medical devices. In this work, a novel technique to construct a microscale extrinsic fiber-optic sensor with a confined air cavity and sub-micron geometric resolution is presented. The confined air cavity is enclosed between a 3 µm thick pressure-sensitive distal diaphragm and a proximal temperature-sensitive plano-convex microlens segment unresponsive to changes in external pressure. Simultaneous pressure and temperature measurements are possible through optical interrogation via phase-resolved low-coherence interferometry (LCI). Upon characterization in a simulated intravascular environment, we find these sensors capable of detecting pressure changes down to 0.11 mmHg (in the range of 760 to 1060 mmHg) and temperature changes of 0.036 °C (in the range 34 to 50 °C). By virtue of these sensitivity values suited to intravascular physiological monitoring, and the scope of design flexibility enabled by the precision-fabricated photoresist microstructure, it is envisaged that this technique will enable construction of a wide range of fiber-optic sensors for guiding minimally invasive medical procedures.

Photodynamic Therapy in Primary Breast Cancer.

Photodynamic therapy (PDT) is a technique for producing localized necrosis with light after prior administration of a photosensitizing agent. This study investigates the nature, safety, and efficacy of PDT for image-guided treatment of primary breast cancer. We performed a phase I/IIa dose escalation study in 12 female patients with a new diagnosis of invasive ductal breast cancer and scheduled to undergo mastectomy as a first treatment. The photosensitizer verteporfin (0.4 mg/kg) was administered intravenously followed by exposure to escalating light doses (20, 30, 40, 50 J; 3 patients per dose) delivered via a laser fiber positioned interstitially under ultrasound guidance. MRI (magnetic resonance imaging) scans were performed prior to and 4 days after PDT. Histological examination of the excised tissue was performed. PDT was well tolerated, with no adverse events. PDT effects were detected by MRI in 7 patients and histology in 8 patients, increasing in extent with the delivered light dose, with good correlation between the 2 modalities. Histologically, there were distinctive features of PDT necrosis, in contrast to spontaneous necrosis. Apoptosis was detected in adjacent normal tissue. Median follow-up of 50 months revealed no adverse effects and outcomes no worse than a comparable control population. This study confirms a potential role for PDT in the management of early breast cancer.

Elastic scattering spectroscopy for early detection of breast cancer: partially supervised Bayesian image classification of scanned sentinel lymph nodes.

Sentinel lymph node biopsy is a standard diagnosis procedure to determine whether breast cancer has spread to the lymph glands in the armpit (the axillary nodes). The metastatic status of the sentinel node (the first node in the axillary chain that drains the affected breast) is the determining factor in surgery between conservative lumpectomy and more radical mastectomy including axillary node excision. The traditional assessment of the node requires sample preparation and pathologist interpretation. An automated elastic scattering spectroscopy (ESS) scanning device was constructed to take measurements from the entire cut surface of the excised sentinel node and to produce ESS images for cancer diagnosis. Here, we report on a partially supervised image classification scheme employing a Bayesian multivariate, finite mixture model with a Markov random field (MRF) spatial prior. A reduced dimensional space was applied to represent the scanning data of the node by a statistical image, in which normal, metastatic, and nonnodal-tissue pixels are identified. Our results show that our model enables rapid imaging of lymph nodes. It can be used to recognize nonnodal areas automatically at the same time as diagnosing sentinel node metastases with sensitivity and specificity of 85% and 94%, respectively. ESS images can help surgeons by providing a reliable and rapid intraoperative determination of sentinel nodal metastases in breast cancer.

Design of sEMG assembly to detect external anal sphincter activity: a proof of concept.

OBJECTIVE: Conditional trans-rectal stimulation of the pudendal nerve could provide a viable solution to treat hyperreflexive bladder in spinal cord injury. A set threshold of the amplitude estimate of the external anal sphincter surface electromyography (sEMG) may be used as the trigger signal. The efficacy of such a device should be tested in a large scale clinical trial. As such, a probe should remain in situ for several hours while patients attend to their daily routine; the recording electrodes should be designed to be large enough to maintain good contact while observing design constraints. The objective of this study was to arrive at a design for intra-anal sEMG recording electrodes for the subsequent clinical trials while deriving the possible recording and processing parameters. APPROACH: Having in mind existing solutions and based on theoretical and anatomical considerations, a set of four multi-electrode probes were designed and developed. These were tested in a healthy subject and the measured sEMG traces were recorded and appropriately processed. MAIN RESULTS: It was shown that while comparatively large electrodes record sEMG traces that are not sufficiently correlated with the external anal sphincter contractions, smaller electrodes may not maintain a stable electrode tissue contact. It was shown that 3 mm wide and 1 cm long electrodes with 5 mm inter-electrode spacing, in agreement with Nyquist sampling, placed 1 cm from the orifice may intra-anally record a sEMG trace sufficiently correlated with external anal sphincter activity. SIGNIFICANCE: The outcome of this study can be used in any biofeedback, treatment or diagnostic application where the activity of the external anal sphincter sEMG should be detected for an extended period of time.

Through-needle all-optical ultrasound imaging in vivo: a preclinical swine study.

High-frequency ultrasound imaging can provide exquisite visualizations of tissue to guide minimally invasive procedures. Here, we demonstrate that an all-optical ultrasound transducer, through which light guided by optical fibers is used to generate and receive ultrasound, is suitable for real-time invasive medical imaging in vivo. Broad-bandwidth ultrasound generation was achieved through the photoacoustic excitation of a multiwalled carbon nanotube-polydimethylsiloxane composite coating on the distal end of a 300-µm multi-mode optical fiber by a pulsed laser. The interrogation of a high-finesse Fabry-Pérot cavity on a single-mode optical fiber by a wavelength-tunable continuous-wave laser was applied for ultrasound reception. This transducer was integrated within a custom inner transseptal needle (diameter 1.08 mm; length 78 cm) that included a metallic septum to acoustically isolate the two optical fibers. The use of this needle within the beating heart of a pig provided unprecedented real-time views (50 Hz scan rate) of cardiac tissue (depth: 2.5 cm; axial resolution: 64 µm) and revealed the critical anatomical structures required to safely perform a transseptal crossing: the right and left atrial walls, the right atrial appendage, and the limbus fossae ovalis. This new paradigm will allow ultrasound imaging to be integrated into a broad range of minimally invasive devices in different clinical contexts.

Disulfonated tetraphenyl chlorin (TPCS2a)-induced photochemical internalisation of bleomycin in patients with solid malignancies: a phase 1, dose-escalation, first-in-man trial.

BACKGROUND: Photochemical internalisation, a novel minimally invasive treatment, has shown promising preclinical results in enhancing and site-directing the effect of anticancer drugs by illumination, which initiates localised chemotherapy release. We assessed the safety and tolerability of a newly developed photosensitiser, disulfonated tetraphenyl chlorin (TPCS2a), in mediating photochemical internalisation of bleomycin in patients with advanced and recurrent solid malignancies. METHODS: In this phase 1, dose-escalation, first-in-man trial, we recruited patients (aged ≥18 to <85 years) with local recurrent, advanced, or metastatic cutaneous or subcutaneous malignancies who were clinically assessed as eligible for bleomycin chemotherapy from a single centre in the UK. Patients were given TPCS2a on day 0 by slow intravenous injection, followed by a fixed dose of 15 000 IU/m(2) bleomycin by intravenous infusion on day 4. After 3 h, the surface of the target tumour was illuminated with 652 nm laser light (fixed at 60 J/cm(2)). The TPCS2a starting dose was 0·25 mg/kg and was then escalated in successive dose cohorts of three patients (0·5, 1·0, and 1·5 mg/kg). The primary endpoints were safety and tolerability of TPCS2a; other co-primary endpoints were dose-limiting toxicity and maximum tolerated dose. The primary analysis was per protocol. This study is registered with ClinicalTrials.gov, number NCT00993512, and has been completed. FINDINGS: Between Oct 3, 2009, and Jan 14, 2014, we recruited 22 patients into the trial. 12 patients completed the 3-month follow-up period. Adverse events related to photochemical internalisation were either local, resulting from the local inflammatory process, or systemic, mostly as a result of the skin-photosensitising effect of TPCS2a. The most common grade 3 or worse adverse events were unexpected higher transient pain response (grade 3) localised to the treatment site recorded in nine patients, and respiratory failure (grade 4) noted in two patients. One dose-limiting toxicity was reported in the 1·0 mg/kg cohort (skin photosensitivity [grade 2]). Dose-limiting toxicities were reported in two of three patients at a TPCS2a dose of 1·5 mg/kg (skin photosensitivity [grade 3] and wound infection [grade 3]); thus, the maximum tolerated dose of TPCS2a was 1·0 mg/kg. Administration of TPCS2a was found to be safe and tolerable by all patients. No deaths related to photochemical internalisation treatment occurred. INTERPRETATION: TPCS2a-mediated photochemical internalisation of bleomycin is safe and tolerable. We identified TPCS2a 0·25 mg/kg as the recommended treatment dose for future trials. FUNDING: PCI Biotech.

Correction: Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method.

[This corrects the article DOI: 10.1371/journal.pone.0142099.].

Photographic-Based Optical Evaluation of Tissues and Biomaterials Used for Corneal Surface Repair: A New Easy-Applied Method.

PURPOSE: Tissues and biomaterials used for corneal surface repair require fulfilling specific optical standards prior to implantation in the patient. However, there is not a feasible evaluation method to be applied in clinical or Good Manufacturing Practice settings. In this study, we describe and assess an innovative easy-applied photographic-based method (PBM) for measuring functional optical blurring and transparency in corneal surface grafts. METHODS: Plastic compressed collagen scaffolds (PCCS) and multilayered amniotic membranes (AM) samples were optically and histologically evaluated. Transparency and image blurring measures were obtained by PBM, analyzing photographic images of a standardized band pattern taken through the samples. These measures were compared and correlated to those obtained applying the Inverse Adding-Doubling (IAD) technique, which is the gold standard method. RESULTS: All the samples used for optical evaluation by PBM or IAD were histological suitable. PCCS samples presented transmittance values higher than 60%, values that increased with increasing wavelength as determined by IAD. The PBM indicated that PCCS had a transparency ratio (TR) value of 80.3 ± 2.8%, with a blurring index (BI) of 50.6 ± 4.2%. TR and BI obtained from the PBM showed a high correlation (ρ>|0.6|) with the diffuse transmittance and the diffuse reflectance, both determined using the IAD (p<0.005). The AM optical properties showed that there was a largely linear relationship between the blurring and the number of amnion layers, with more layers producing greater blurring. CONCLUSIONS: This innovative proposed method represents an easy-applied technique for evaluating transparency and blurriness of tissues and biomaterials used for corneal surface repair.

Development of Photodynamic Antimicrobial Chemotherapy (PACT) for Clostridium difficile.

BACKGROUND: Clostridium difficile is the leading cause of antibiotic-associated diarrhoea and pseudo membranous colitis in the developed world. The aim of this study was to explore whether Photodynamic Antimicrobial Chemotherapy (PACT) could be used as a novel approach to treating C. difficile infections. METHODS: PACT utilises the ability of light-activated photosensitisers (PS) to produce reactive oxygen species (ROS) such as free radical species and singlet oxygen, which are lethal to cells. We screened thirteen PS against C. difficile planktonic cells, biofilm and germinating spores in vitro, and cytotoxicity of effective compounds was tested on the colorectal adenocarcinoma cell-line HT-29. RESULTS: Three PS were able to kill 99.9% of bacteria in both aerobic and anaerobic conditions, both in the planktonic state and in a biofilm, after exposure to red laser light (0.2 J/cm2) without harming model colon cells. The applicability of PACT to eradicate C. difficile germinative spores indirectly was also shown, by first inducing germination with the bile salt taurocholate, followed by PACT. CONCLUSION: This innovative and simple approach offers the prospect of a new antimicrobial therapy using light to treat C. difficile infection of the colon.

Broadband miniature optical ultrasound probe for high resolution vascular tissue imaging.

An all-optical ultrasound probe for vascular tissue imaging was developed. Ultrasound was generated by pulsed laser illumination of a functionalized carbon nanotube composite coating on the end face of an optical fiber. Ultrasound was detected with a Fabry-Pérot (FP) cavity on the end face of an adjacent optical fiber. The probe diameter was < 0.84 mm and had an ultrasound bandwidth of ~20 MHz. The probe was translated across the tissue sample to create a virtual linear array of ultrasound transmit/receive elements. At a depth of 3.5 mm, the axial resolution was 64 µm and the lateral resolution was 88 µm, as measured with a carbon fiber target. Vascular tissues from swine were imaged ex vivo and good correspondence to histology was observed.

Interventional Photoacoustic Imaging of the Human Placenta with Ultrasonic Tracking for Minimally Invasive Fetal Surgeries.

Image guidance plays a central role in minimally invasive fetal surgery such as photocoagulation of inter-twin placental anastomosing vessels to treat twin-to-twin transfusion syndrome (TTTS). Fetoscopic guidance provides insufficient sensitivity for imaging the vasculature that lies beneath the fetal placental surface due to strong light scattering in biological tissues. Incomplete photocoagulation of anastamoses is associated with postoperative complications and higher perinatal mortality. In this study, we investigated the use of multi-spectral photoacoustic (PA) imaging for better visualization of the placental vasculature. Excitation light was delivered with an optical fiber with dimensions that are compatible with the working channel of a fetoscope. Imaging was performed on an ex vivo normal term human placenta collected at Caesarean section birth. The photoacoustically-generated ultrasound signals were received by an external clinical linear array ultrasound imaging probe. A vein under illumination on the fetal placenta surface was visualized with PA imaging, and good correspondence was obtained between the measured PA spectrum and the optical absorption spectrum of deoxygenated blood. The delivery fiber had an attached fiber optic ultrasound sensor positioned directly adjacent to it, so that its spatial position could be tracked by receiving transmissions from the ultrasound imaging probe. This study provides strong indications that PA imaging in combination with ultrasonic tracking could be useful for detecting the human placental vasculature during minimally invasive fetal surgery.

Small bowel obstruction in the virgin abdomen: the need for a mandatory laparotomy explored.

BACKGROUND: A laparotomy is still considered mandatory for patients without previous abdominal surgery presenting with a small bowel obstruction (SBO) because of a perceived high incidence of underlying lesions. However, there is no evidence in literature to support this assumption. We analyzed the etiology of SBO in this subgroup of patients to establish the need for a mandatory laparotomy. METHODS: A retrospective analysis was conducted over a 5-year period. Basic demographics, radiology results, operative findings, and outpatient investigations were analyzed. RESULTS: Of 689 patients presenting with an SBO, a total of 62 patients, 9.0%, had a virgin abdomen. A known underlying disease (inflammatory bowel disease, malignancy) was the cause in 13 patients. The remaining 49 patients had adhesions in 75.5% and a newly diagnosed malignancy in 10.2% as a cause. CONCLUSIONS: Adhesions are by far the most likely cause of SBO in patients without previous abdominal surgery followed by a small number of newly diagnosed malignancies. Both prevalences are in equal proportion to patients with previous abdominal surgery. A trial of nonoperative management may therefore be justified.

A microchannel neuroprosthesis for bladder control after spinal cord injury in rat.

A severe complication of spinal cord injury is loss of bladder function (neurogenic bladder), which is characterized by loss of bladder sensation and voluntary control of micturition (urination), and spontaneous hyperreflexive voiding against a closed sphincter (detrusor-sphincter dyssynergia). A sacral anterior root stimulator at low frequency can drive volitional bladder voiding, but surgical rhizotomy of the lumbosacral dorsal roots is needed to prevent spontaneous voiding and dyssynergia. However, rhizotomy is irreversible and eliminates sexual function, and the stimulator gives no information on bladder fullness. We designed a closed-loop neuroprosthetic interface that measures bladder fullness and prevents spontaneous voiding episodes without the need for dorsal rhizotomy in a rat model. To obtain bladder sensory information, we implanted teased dorsal roots (rootlets) within the rat vertebral column into microchannel electrodes, which provided signal amplification and noise suppression. As long as they were attached to the spinal cord, these rootlets survived for up to 3 months and contained axons and blood vessels. Electrophysiological recordings showed that half of the rootlets propagated action potentials, with firing frequency correlated to bladder fullness. When the bladder became full enough to initiate spontaneous voiding, high-frequency/amplitude sensory activity was detected. Voiding was abolished using a high-frequency depolarizing block to the ventral roots. A ventral root stimulator initiated bladder emptying at low frequency and prevented unwanted contraction at high frequency. These data suggest that sensory information from the dorsal root together with a ventral root stimulator could form the basis for a closed-loop bladder neuroprosthetic.

CO2 laser of oral dysplasia: clinicopathological features of recurrence and malignant transformation.

The use of the CO(2) laser in the management of oral dysplastic lesions has become a more common practice. Very few studies have evaluated recurrence, residual disease malignant transformation, and overall outcome in patients undergoing such a procedure. In this prospective study, a total of 123 oral dysplastic lesions from 77 consecutive patients were treated with the CO(2) laser (resection and/or ablation). The average age was 58 ± 4.8 years. The patients' recovery was uneventful and no complications were reported. Comparisons with the clinical and histopathological features and rate of recurrence as well as malignant transformation were made. The patients were followed-up for a mean of 6.4 years, and biopsies taken in case of changes suggestive of malignant development. Homogenous leukoplakias were identified in 31 patients, non-homogenous leukoplakias in 34 patients, whereas 12 patients had erythroplakias. Ex- and life-long smokers formed 88.3% of the recruited patients. While people who currently smoke and drink formed 55.8% of the cohort. Erythroplakias were solely identified in heavy life-long smokers. The most common identified primary anatomical locations were the lateral border of tongue, floor of mouth, and buccal mucosa. Moderate dysplasia was identified in 42 patients while 18 patients had severe dysplasia. Laser resection margins in selected cases (68 patients) were clear in 53 and showed mild-moderate dysplasia in the involved margins. The rate of recurrence had no significant association with the location but the severity of epithelial dysplasia. The rate of first recurrence after laser surgery was approximately 19.5%. Malignant transformation was observed in eight patients (10.4%), in the tongue and the floor of mouth. Recurrence and malignant transformation was mainly identified in erythroplakias and non-homogenous leukoplakias. Laser resection/ablation is recommended for oral dysplasia to prevent not only recurrence and malignant transformation but also postoperative oral dysfunction encountered by other conventional modalities.

Prospective evaluation of 110 patients following ultrasound-guided photodynamic therapy for deep seated pathologies.

INTRODUCTION: Photodynamic therapy, the fourth oncological interventional modality has proved its success in the management of variety of pathologies involving the human body. Our aim in this prospective clinical study was to continue evaluating the outcome following ultrasound-guided interstitial PDT of pathologies involving the human body. Patients' reports on quality of life with clinical and radiological evaluation were the main end point parameters used to assess the outcome. MATERIALS AND METHODS: One hundred and ten patients were referred to the UCLH Head and Neck Centre, London for treatment of various deep-seated pathologies. These included tumours in the head and neck as well as vascular anomalies of the limbs. After multidisciplinary discussion, all patients underwent interstitial photodynamic therapy (iPDT) under general anaesthesia, using 0.15mg/kg mTHPC as the photosensitising agent. Following treatment, patients were followed-up for a mean of 26 months. RESULTS: Four out of five patients who presented with visual problems reported improvement after treatment. Also, 27/32 reported improvement of breathing. Improvement of swallowing was reported by 30/37 patients; while speech improvement was evident in 22/29 patients and 43/52 reported reduction in the disfigurement caused by their pathology. Seven out of nine patients with impeded limb function reported some degree of improvement. Clinical assessment showed that nearly half of the patients had "good response" to the treatment and 5 became disease free. Moderate clinical response was reported by 39 patients. Radiological assessment comparing radiological imaging 6-week post-PDT to the baseline showed moderate response in 45 patients and significant response in 32 patients. CONCLUSION: This study on 110 patients with deep-seated pathologies undergoing interstitial photodynamic therapy provided further evidence that PDT is a useful modality in the management of these pathologies that are otherwise resistant to conventional treatments, and with minimal side effects.