MR-based artificial intelligence model to assess response to therapy in locally advanced rectal cancer.

PURPOSE: To develop and validate an Artificial Intelligence (AI) model based on texture analysis of high-resolution T2 weighted MR images able 1) to predict pathologic Complete Response (CR) and 2) to identify non-responders (NR) among patients with locally-advanced rectal cancer (LARC) after receiving neoadjuvant chemoradiotherapy (CRT). METHOD: Fifty-five consecutive patients with LARC were retrospectively enrolled in this study. Patients underwent 3 T Magnetic Resonance Imaging (MRI) acquiring T2-weighted images before, during and after CRT. All patients underwent complete surgical resection and histopathology was the gold standard. Textural features were automatically extracted using an open-source software. A sub-set of statistically significant textural features was selected and two AI models were built by training a Random Forest (RF) classifier on 28 patients (training cohort). Model performances were estimated on 27 patients (validation cohort) using a ROC curve and a decision curve analysis. RESULTS: Sixteen of 55 patients achieved CR. The AI model for CR classification showed good discrimination power with mean area under the receiver operating curve (AUC) of 0.86 (95% CI: 0.70, 0.94) in the validation cohort. The discriminatory power for the NR classification showed a mean AUC of 0.83 (95% CI: 0.71,0.92). Decision curve analysis confirmed higher net patient benefit when using AI models compared to standard-of-care. CONCLUSIONS: AI models based on textural features of MR images of patients with LARC may help to identify patients who will show CR at the end of treatment and those who will not respond to therapy (NR) at an early stage of the treatment.

The ß- radio-guided surgery: Method to estimate the minimum injectable activity from ex-vivo test.

PURPOSE: Radio-guided surgery with ß- decays is a novel technique under investigation. One of the main advantages is its capability to detect small (⩽0.1 ml) samples after injecting the patient with low activity of radiopharmaceutical. This paper presents an experimental method to quantify this feature based on ex-vivo tests on specimens from meningioma patients. METHODS: Patients were enrolled on the basis of the standard uptake value (SUV) and the tumour-to-non-tumour activity ratio (TNR) resulted from 68Ga-DOTATOC PET exams. After injecting the patients with 93-167 MBq of 90Y-DOTATOC, 26 samples excised during surgery were analyzed with a ß- probe. The radioactivity expected on the neoplastic specimens was estimated according to the SUV found in the PET scan and the correlation with the measured counts was studied. The doses to surgeon and medical personnel were also evaluated. RESULTS: Even injecting as low as 1.4 MBq/kg of radiotracer, tumour residuals of 0.1 ml can be detected. A negligible dose to the medical personnel was confirmed. CONCLUSIONS: Radio-guided surgery with ß- decays is a feasible technique with a low radiation dose for both personnel and patient, in particular if the patient is injected with the minimum required activity. A correlation greater than 80% was observed between the measured counts and the expected activity for the lesion samples based on the individual SUV and the TNR. This makes identifiable the minimum injectable radiotracer activity for cases where 90Y is the utilized radionuclide.

Secondary radiation measurements for particle therapy applications: charged particles produced by 4He and 12C ion beams in a PMMA target at large angle.

Proton and carbon ion beams are used in the clinical practice for external radiotherapy treatments achieving, for selected indications, promising and superior clinical results with respect to x-ray based radiotherapy. Other ions, like [Formula: see text] have recently been considered as projectiles in particle therapy centres and might represent a good compromise between the linear energy transfer and the radiobiological effectiveness of [Formula: see text] ion and proton beams, allowing improved tumour control probability and minimising normal tissue complication probability. All the currently used p, [Formula: see text] and [Formula: see text] ion beams allow achieving sharp dose gradients on the boundary of the target volume, however the accurate dose delivery is sensitive to the patient positioning and to anatomical variations with respect to photon therapy. This requires beam range and/or dose release measurement during patient irradiation and therefore the development of dedicated monitoring techniques. All the proposed methods make use of the secondary radiation created by the beam interaction with the patient and, in particular, in the case of [Formula: see text] ion beams are also able to exploit the significant charged radiation component. Measurements performed to characterise the charged secondary radiation created by [Formula: see text] and [Formula: see text] particle therapy beams are reported. Charged secondary yields, energy spectra and emission profiles produced in a poly-methyl methacrylate (PMMA) target by [Formula: see text] and [Formula: see text] beams of different therapeutic energies were measured at 60° and 90° with respect to the primary beam direction. The secondary yield of protons produced along the primary beam path in a PMMA target was obtained. The energy spectra of charged secondaries were obtained from time-of-flight information, whereas the emission profiles were reconstructed exploiting tracking detector information. The obtained measurements are in agreement with results reported in the literature and suggests the feasibility of range monitoring based on charged secondary particle detection: the implications for particle therapy monitoring applications are also discussed.

A mini-invasive tenolysis of the flexor tendons following hand fractures: case series.

INTRODUCTION: The treatment of the flexor tendon adhesions following phalanx and metacarpal fractures, in closed or open injuries, is a great challenge for the hand surgeon. The outcomes are often poor, because of the severity of the lesion and the aggressiveness of the surgical procedure of the secondary tenolysis. MATERIALS AND METHODS: The authors describe the technical findings and the results of a new mini-invasive tenolysis in order to treat the adhesions in zone 1 and 2 of the fingers, following phalangeal and metacarpal fractures. With an atraumatic Allis or Duval surgical forceps, the flexor tendons are separately and gently tracted making a twisting movement on themselves until the adhesions were torn and the tendons appeared released. RESULTS: The relevant outcomes achieved show this technique is very useful to treat tendon adhesions, without adding trauma and scare to the tendinous canal and surrounding soft tissues.

Stage IV Kienböck's disease: Proximal row carpectomy and application of RCPI implant.

Kienböck disease is an aseptic osteonecrosis of the lunate, which gradually leads to total carpal collapse. Lichtman's classification relates radiographic evidence of wrist damage to four different stages and supports surgical decision-making. This study pertains to six patients (2 males and 4 females) affected by stage IV Kienböck's disease who underwent proximal row carpectomy and received an RCPI implant. The clinical outcomes consisted of wrist range of motion (ROM), pain on a VAS scale (0-10), the DASH score and the patient's level of satisfaction. The mean follow-up was 27.6 months (16-36). Pain relief and improvements in wrist flexion - extension ROM, radial - ulnar deviation and strength were achieved in every patient. There were no cases of implant failure or dislocation. Considering the good results obtained, we believe that proximal row carpectomy associated with the use of a pyrocarbon RCPI implant is a valid surgical technique for the treatment of stage IV Kienböck's disease. It is a good alternative to carpal fusion, which leads to wrist immobility, and to total wrist joint replacement, which has a high incidence of dislocation and fracture.

Secondary radiation measurements for particle therapy applications: prompt photons produced by 4He, 12C and 16O ion beams in a PMMA target.

Charged particle beams are used in particle therapy (PT) to treat oncological patients due to their selective dose deposition in tissues with respect to the photons and electrons used in conventional radiotherapy. Heavy (Z > 1) PT beams can additionally be exploited for their high biological effectiveness in killing cancer cells. Nowadays, protons and carbon ions are used in PT clinical routines. Recently, interest in the potential application of helium and oxygen beams has been growing. With respect to protons, such beams are characterized by their reduced multiple scattering inside the body, increased linear energy transfer, relative biological effectiveness and oxygen enhancement ratio. The precision of PT demands online dose monitoring techniques, crucial to improving the quality assurance of any treatment: possible patient mis-positioning and biological tissue changes with respect to the planning CT scan could negatively affect the outcome of the therapy. The beam range confined in the irradiated target can be monitored thanks to the neutral or charged secondary radiation emitted by the interactions of hadron beams with matter. Among these secondary products, prompt photons are produced by nuclear de-excitation processes, and at present, different dose monitoring and beam range verification techniques based on prompt-γ detection are being proposed. It is hence of importance to perform γ yield measurement in therapeutic-like conditions. In this paper we report on the yields of prompt photons produced by the interaction of helium, carbon and oxygen ion beams with a poly-methyl methacrylate (PMMA) beam stopping target. The measurements were performed at the Heidelberg Ion-Beam Therapy Center (HIT) with beams of different energies. An LYSO scintillator, placed at [Formula: see text] and [Formula: see text] with respect to the beam direction, was used as the photon detector. The obtained γ yields for the carbon ion beams are compared with results from the literature, while no other results from helium and oxygen beams have been published yet. A discussion on the expected resolution of a slit camera detector is presented, demonstrating the feasibility of a prompt-γ-based monitoring technique for PT treatments using helium, carbon and oxygen ion beams.

Secondary radiation measurements for particle therapy applications: nuclear fragmentation produced by 4He ion beams in a PMMA target.

Nowadays there is a growing interest in particle therapy treatments exploiting light ion beams against tumors due to their enhanced relative biological effectiveness and high space selectivity. In particular promising results are obtained by the use of 4He projectiles. Unlike the treatments performed using protons, the beam ions can undergo a fragmentation process when interacting with the atomic nuclei in the patient body. In this paper the results of measurements performed at the Heidelberg Ion-Beam Therapy center are reported. For the first time the absolute fluxes and the energy spectra of the fragments-protons, deuterons, and tritons-produced by 4He ion beams of 102, 125 and 145 MeV u-1 energies on a poly-methyl methacrylate target were evaluated at different angles. The obtained results are particularly relevant in view of the necessary optimization and review of the treatment planning software being developed for clinical use of 4He beams in clinical routine and the relative bench-marking of Monte Carlo algorithm predictions.

First ex vivo validation of a radioguided surgery technique with ß-radiation.

PURPOSE: A radio-guided surgery technique with ß(-)-emitting radio-tracers was suggested to overcome the effect of the large penetration of γ radiation. The feasibility studies in the case of brain tumors and abdominal neuro-endocrine tumors were based on simulations starting from PET images with several underlying assumptions. This paper reports, as proof-of-principle of this technique, an ex vivo test on a meningioma patient. This test allowed to validate the whole chain, from the evaluation of the SUV of the tumor, to the assumptions on the bio-distribution and the signal detection. METHODS: A patient affected by meningioma was administered 300MBq of (90)Y-DOTATOC. Several samples extracted from the meningioma and the nearby Dura Mater were analyzed with a ß(-) probe designed specifically for this radio-guided surgery technique. The observed signals were compared both with the evaluation from the histology and with the Monte Carlo simulation. RESULTS: we obtained a large signal on the bulk tumor (105cps) and a significant signal on residuals of ∼0.2ml (28cps). We also show that simulations predict correctly the observed yields and this allows us to estimate that the healthy tissues would return negligible signals (≈1cps). This test also demonstrated that the exposure of the medical staff is negligible and that among the biological wastes only urine has a significant activity. CONCLUSIONS: This proof-of-principle test on a patient assessed that the technique is feasible with negligible background to medical personnel and confirmed that the expectations obtained with Monte Carlo simulations starting from diagnostic PET images are correct.

An arthroscopic-assisted minimal invasive method for the reconstruction of the scapho-lunate ligament using a bone-ligament-bone graft.

UNLABELLED: We report the outcomes of an arthroscopic-assisted minimally invasive technique to reconstruct the scapho-lunate ligament using a bone-ligament-bone graft in 11 patients (11 wrists). The mean follow-up time was 29 months (range 20 to 38). The preoperative mean wrist flexion, extension, grip strength and patient-rated wrist evaluation score values were 61°, 54°, 115 N and 54, respectively. The postoperative mean values were 64°, 58°, 142 N and 15, respectively. There were no statistical differences between the pre- and postoperative wrist flexion and extension, whereas changes in grip strength and patient-rated wrist evaluation score were significant. Scapho-lunate angles decreased significantly from 69° to 60°. Based on our clinical outcomes, this method provides a reliable alterative for the reconstruction of the scapho-lunate ligament in patients with persistent Geissler type 3 and 4 lesions in the short-term. LEVEL OF EVIDENCE: IV.

Personal technique for wrist dorsal approach.

In hand disorders surgical procedures are more and more widely used and often it's necessary to approach the wrist by the dorsal way. Beneath anatomy of this region is well known, there is still room enough to develop new surgical exposure techniques mostly related to physiology and biomechanics. Our goals are to present an innovative surgical dorsal exposure of the wrist, to show its use for different problems solving, and to evaluate its mini-invasive and functional outcome. Our inedited surgical technique is presented. Since November 1999 to February 2008, this technique has been used by the same surgeon in 60 cases for different pathologies and procedures: 14 SNAC-SLAC wrists III-IV treated by proximal row resection and Resurface-Capitate Pyrocarbon Implant (RCPI), 2 Fenton syndromes by bone graft and RCPI, 6 SNACSLAC II by proximal row resection +/- radial styloidectomy, 2 SLAC III by scaphoidectomy and capito-lunate arthrodesis, 12 scapho-lunate recent dissociations by ligamentoplasty (double approach), 4 scapho-lunate inveterate dissociations by Cuenod Saffar-Romano modified technique and 4 by synthetic ligaments, 1 fracture of the scaphoid proximal pole by synthesis-revascularization-S.L.ligament reconstruction, 15 Kienbock's diseases revascularized by II m.c. artery +/- radial osteotomy. Patients have been evaluated at follow up through the DASH disability questionnaire, the Mayo score for the force, ROM, pain, satisfaction grade. Results are good and encouraging for these applications. In conclusion this new technique with its limited exposure permits an early mobilization with a lower risk of stiffness and can be considered mini-invasive.

Salvage of a post-traumatic arthritic wrist using the scaphoid as an osteochondral graft.

The authors describe a case of post-traumatic wrist arthritis with an osteochondral defect in the scaphoid fossa of the radius. The patient was treated with proximal row carpectomy, radial styloidectomy and reconstruction of the defect using the proximal half of the scaphoid as an autologous osteochondral graft. Pain relief was achieved while wrist motion and strength were improved. The carpal bones are a source of osteochondral grafts and can be used to expand the indications of motion-preserving wrist salvage procedures.

A novel radioguided surgery technique exploiting ß(-) decays.

The background induced by the high penetration power of the radiation is the main limiting factor of the current radio-guided surgery (RGS). To partially mitigate it, a RGS with ß(+)-emitting radio-tracers has been suggested in literature. Here we propose the use of ß(-)-emitting radio-tracers and ß(-) probes and discuss the advantage of this method with respect to the previously explored ones: the electron low penetration power allows for simple and versatile probes and could extend RGS to tumours for which background originating from nearby healthy tissue makes probes less effective. We developed a ß(-) probe prototype and studied its performances on phantoms. By means of a detailed simulation we have also extrapolated the results to estimate the performances in a realistic case of meningioma, pathology which is going to be our first in-vivo test case. A good sensitivity to residuals down to 0.1 ml can be reached within 1 s with an administered activity smaller than those for PET-scans thus making the radiation exposure to medical personnel negligible.

The use of a pyrocarbon capitate resurfacing implant in chronic wrist disorders.

The present study describes the technique and results of proximal row carpectomy with resection of the head of the capitate and replacement with a pyrocarbon capitate resurfacing implant. The major indication for surgical treatment was arthritic changes on the head of the capitate. Patients were assessed by range of motion, grip strength, pain and functional scoring, and radiographic studies. In most patients, wrist function was improved and pain relief was obtained. This surgical procedure may represent a good alternative to total and partial wrist arthrodesis.

Chronic transscaphoid, transcapitate perilunate fracture dislocation of the wrist: Fenton's syndrome.

The authors report about chronic Fenton's syndrome. This rare injury of the wrist is characterized by scapho-capitate fracture accompanied by 180° rotation of the head of capitate and associated perilunate dislocation. Two patients suffering from chronic Fenton's syndrome were treated with pyrocarbon capitate resurfacing prosthesis. Patients were evaluated according to the wrist range of motion, Mayo modified wrist and DASH scores. In conclusion, prosthetic surgery may achieve satisfactory results for this rare and diagnostically challenging syndrome.