[Factors influencing drainage productivity in breast reduction: A retrospective study of 222 breasts]. / Facteurs influençant la productivité du drainage dans la réduction mammaire : étude rétrospective sur 222 seins.

INTRODUCTION: The objective of this study is to highlight the factors that influence drain productivity in reduction mastoplasty. MATERIALS AND METHODS: We have retrospectively referenced from November 2015 to November 2017 all breast reduction performed in the plastic surgery, reconstructive and esthetic surgery department of the University Hospital of Nancy. A total of 222 breasts were analyzed by listing age, weight, height, Body Mass Index (BMI), smoking status, surgeon, technical used, hospitalization stay, breast volume removed, type and size of drain and their productivity. Multivariate analysis were realised. RESULTS: 118 patients were included with an average age of 42.2 years. The average productivity of drains was 50 millilitres (ml). There was a significant difference in productivity of drainage according to the operator with a median ranging from 10ml to 60ml (P<0.0001). The median was 20ml for 10 Redon-Jost drains versus 50ml for the 16 Redon-Jost drains (P<0.0001). Multivariate analysis of the various factors influencing the total productivity of postoperative drainage showed a relative risk of 1.16 for smokers, 0.24 for one surgeon, 1.68 for the Skoog technique, and 1.000 for breast volume removed. CONCLUSION: The drain productivity is not predictable before a breast reduction. Indeed, none of the characteristics studied have sufficient influence on the productivity of the drains.

[Perforating flap for covering sacro-coccygeal cysts: About 8 cases]. / Lambeau perforant pour couverture des kystes sacrococcygiens : à propos de 8 cas.

INTRODUCTION: Multiple surgical revisions (exeresis and directed healing) of recurrent pilonidal cysts are sources of unstable scars. Chronic ulcerations often appear with or without authentic recidivism. A local fasciocutaneous perforating flap based on the parasacral arteries would bring healthy tissue and avoid the disadvantages of conventional techniques (musculo-cutaneous or random). MATERIALS AND METHODS: A series of 8 cases of transposition flap covering based on parasacral perforators, in multi-operated patients. The perforators are identified by Doppler probe before the gesture, then the flap is traced obliquely according to the size of the loss of substance. The gesture is short, not morbid and accessible to all by a technique that excludes fine dissection of the pedicle. The duration of hospitalization is 2days. RESULTS: Despite two minor and resolving complications (a hematoma and a disunion of the donor sit) the healing was complete and without recurrence in all patients at 2years, with 100% satisfaction. CONCLUSION: This reliable and reproducible simple flap becomes the reference technique in our department for the sequelae of recurrent sacro-coccygeal cyst.

[Use of pedicled dorsal muscle flap combined with negative pressure therapy in the management of postpneumonectomy septic complications]. / Utilisation du lambeau de muscle grand dorsal pédiculé combiné à la thérapie à pression négative dans la prise en charge des complications septiques post-pneumonectomie.

SUBJECT: The objective of this study is to report our experience in the management of septic complications arising from pulmonary resection surgery by placing a pedicled upper back muscle flap associated with dressings by therapy. Negative pressure in all patients supported in our center from November 2015 to March 2018. MATERIAL AND METHODS: Characteristics of fourteen patients with a pedicled dorsal muscle flap in the context of chronic empyema associated with bronchopulmonary fistula were identified. Flap placement time, complications, and success rate were assessed. RESULTS: The median flap placement after completion of the open window thoracostomy was 19days [3-65]. The median healing time was 3months. Healing was definitively achieved in 12 patients, a success rate of 86%. CONCLUSION: Through this series we have shown that our coverage by pneumonectomy cavity coverage with an early dorsal muscle flap associated with negative pressure therapy, has a similar mortality rate and success rate to those found in the literature.

Three-dimensional imaging, an important factor of decision in breast augmentation.

INTRODUCTION: Since the beginning of the 21st century, three-dimensional imaging systems have been used more often in plastic surgery, especially during preoperative planning for breast surgery and to simulate the postoperative appearance of the implant in the patient's body. The main objective of this study is to assess the patients' attitudes regarding 3D simulation for breast augmentation. METHOD: A study was conducted, which included women who were operated on for primary breast augmentation. During the consultation, a three-dimensional simulation with Crisalix was done and different sized implants were fitted in the bra. RESULTS: Thirty-eight women were included. The median age was 29.4, and the median prosthesis volume was 310mL. The median rank given regarding the final result was 9 (IQR: 8-9). Ninety percent of patients agreed (66% absolutely agreed, and 24% partially agreed) that the final product after breast augmentations was similar to the Crisalix simulation. Ninety-three percent of the patients believed that the three-dimensional simulation helped them choose their prosthesis (61% a lot and 32% a little). After envisaging a breast enlargement, patients estimated that the Crisalix system was absolutely necessary (21%), very useful (32%), useful (45%), or unnecessary (3%). Regarding prosthesis choice, an equal number of women preferred the 3D simulation (19 patients) as preferred using different sizes of implants in the bra (19 patients). CONCLUSION: The present study demonstrated that 3D simulation is actually useful for patients in order to envisage a breast augmentation. But it should be used as a complement to the classic method of trying different sized breast implants in the bra.

Intraoperative instillation of ropivacaine during the placement of sub-muscular cosmetic breast implants: Is there a clinical benefit?

INTRODUCTION: The sub-muscular placement of cosmetic breast implants leads to substantial pain due to the muscular distention. The aim of this study was to assess the efficiency of intraoperative ropivacaine instillation to reduce postoperative pain the day after surgery. MATERIAL AND METHODS: We conducted a prospective, controlled, single-blinded study comparing the intraoperative instillation of 7.5mg of ropivacaine through Redon drains with the standard procedure in 72 patients undergoing sub-muscular cosmetic breast augmentation for the first time. RESULTS: Pain at the awakening on postoperative day 1 was 4.8 on a simple numeric pain scale in the treatment group and 5.1 in the control group (P>0.05). On postoperative day 3, pain at awakening was 3.7 in both groups (P>0.05), and on postoperative day 5, pain was 2.8 in the treatment group and 2.7 in the control group (P>0.05). CONCLUSION: Local instillation of ropivacaine in the implant pocket during surgery did not decrease postoperative pain on day 1, day 3 and day 5. From now on, we are able to tell to patients that the postoperative pain after sub-muscular cosmetic breast implants surgery is about 5/10 on postoperative day 1, 4/10 at day 3 and 3/10 at day 5. LEVEL OF EVIDENCE: Level II.

Abdominoplasty and simultaneous laparoscopic ventral hernia repair. Clinical study about 45 patients.

INTRODUCTION: Abdominoplasty procedures sometimes reveal the presence of ventral hernias (umbilical or trocar-site hernias). Our objective is then to deal with the excess abdominal skin and fat tissue at the same time as the ventral hernia. This can be done with a single surgical procedure combining abdominoplasty with umbilical transposition and laparoscopic ventral hernia repair (LVHR) with mesh. The main objective of our study is to assess the outcome of the combined procedure of abdominoplasty and LVHR with mesh, compared to abdominoplasty alone. MATERIALS AND METHODS: A retrospective single-centre cohort study was conducted, including patients operated on with the combined method (ABDO-LVHR group) and patients who underwent abdominoplasty alone (ABDO group). We noted major and minor complications, with infection issues as our main concern. RESULTS: We included 15 patients in the ABDO-LVHR group and 30 in the ABDO group. The results show no statistically significant difference for infectious complications in the ABDO-LVHR group compared to the ABDO group (20% vs 3.3%; P=0.100). There was no instance of complete umbilical necrosis. Other major and minor complications occurred at the rates typically described in the literature without difference between the two groups. CONCLUSION: There was no significant difference between our two groups in terms of infectious complications. LVHR carried out at the same time as abdominoplasty with umbilical transposition is a positive combination of procedures. Further studies are necessary to confirm that the risk in terms of infectious complications is no higher than for abdominoplasty alone. LEVEL OF EVIDENCE: III.

Outcome of 122 delayed breast reconstruction following post-mastectomy radiotherapy: The scarless latissimus dorsi flap with tissue expansion technique.

BACKGROUND: Delayed breast reconstruction with tissue expansion may be risky after radiotherapy, due to the poor skin quality. To permit the use of the tissue expansion procedure, we propose a scarless latissimus dorsi flap to bring tissue trophicity, by a healthy vascularized muscular interface with no donor scar and no patch effect. The objective of this study is to assess the outcome of the tissue expansion technique with scarless latissimus dorsi flap after post-mastectomy radiotherapy. METHODS: All the patients who had benefited of a delayed breast reconstruction after radiotherapy using tissue expansion technique with scarless latissimus dorsi flap, between January 2000 and January 2013, were reviewed. The exclusion criteria were: prior breast reconstruction, or interruption of breast reconstruction procedure due to active metastatic disease requiring ongoing oncological treatment. The complications were identified: failures of reconstruction, implant exposure, wound dehiscence, capsular contracture, deflation of implant, hematoma, infection, and skin necrosis. RESULTS: One hundred and twenty-two breasts were reviewed. The average time between the flap and the expander intervention was: 194±114 SD (28-1051) days. The mean volume of inserted expander was 633±111 SD (350-1100) mL and the mean inflation volume was 578±190 SD (170-1160) mL. The average time between insertion of the expander and insertion of the permanent implant was 132±76 SD (49-683) days. The mean inflation of the implant volume was 368±105 SD (130-620) mL. Forty patients developed at least one complication. The most common complication was the appearance of a capsular contracture requiring a capsulectomy: 11 (9.2%) with permanent implants and 6 (4.9%) with expander. Deflation of implants occurred with six permanent implants and with one expander. There were 3 breast reconstructions failures (two infections and one exposure of implants). CONCLUSION: This procedure offers the advantages that there is no unattractive scar, and that there are low rates of exposure or failed reconstruction.

[Tobacco and plastic surgery: An absolute contraindication?] / Tabac et interventions de chirurgie plastique : vers une contre-indication formelle ?

INTRODUCTION: Smoking increases perioperative risk regarding wound healing, infection rate and failure of microsurgical procedures. There is no present consensus about plastic and aesthetic surgical indications concerning smoking patients. The aim of our study is to analyze French plastic surgeons practices concerning smokers. METHOD: A questionnaire was send by e-mail to French plastic surgeons in order to evaluate their own operative indications: patient information about smoking dangers, pre- and postoperative delay of smoking cessation, type of intervention carried out, smoking cessation supports, use of screening test and smoking limit associated to surgery refusing were studied. Statistical tests were used to compare results according to practitioner activity (liberal or public), own smoking habits and time of installation. RESULTS: In 148 questionnaires, only one surgeon did not explain smoking risk. Of the surgeons, 49.3% proposed smoking-cessation supports, more frequently with public practice (P=0.019). In total, 85.4% of surgeons did not use screening tests. Years of installation affected operative indication with smoking patients (P=0.02). Pre- and postoperative smoking cessation delay were on average respectively 4 and 3 weeks in accordance with literature. CONCLUSION: Potential improvements could be proposed to smoking patients' care: smoking cessation assistance, screening tests, absolute contraindication of some procedures or level of consumption to determine.

[Postoperative quality of life of patients with a bacterial necrotizing dermis-hypodermitis or necrotizing fasciitis, a ten-year study]. / Qualité de vie des patients opérés d'une dermo-hypodermite ou fasciite nécrosante, une étude sur 10ans.

INTRODUCTION: Bacterial necrotizing dermis-hypodermitis and necrotizing fasciitis (BNDH-NF) are serious life-threatening soft-tissue infections. The object is to evaluate the quality of life (QOL) of patients who have been operated in our plastic surgery departement. PATIENTS AND METHODS: This is a retrospective study of cases who have been treated at Nancy University Hospital between 2005 and 2014. We analyzed the perioperative data (demographic, clinical, bacteriological), the surgical data (excision, reconstruction) and the follow up data (consequences, mortality). The quality of life was assessed by the Short-Form 36 score, and the patients' satisfaction was assessed by a four-level scale. RESULTS: We analyzed 23 patients with an average age of 60 years (28-84 years). The main comorbidities were diabetes (43 %) and obesity (39 %). The average number of surgical excision was about 1.9 (1-5) and the average excised body surface area was about 5 % (1-16 %). The short-term mortality was about 17 %. The mortality rate has been statistically correlated with the surgically excised body surface area (short-term 95 days: P=0.02; and long-term: P=0.003). The statistical analysis has shown a strong relative linear relationship between number of surgical excision and the physical score of QOL (P<0.001), between number of surgical excision and mental score of QOL (P=0.032), and between age and physical score of QOL (P≤0.021). The statistical analysis has also shown a strong relative linear relationship between E. coli infections and physical score of QOL (P=0.01). The percentage of patients' satisfaction in our study was evaluated at 86 %. CONCLUSION: We have found that multiple surgical excisions, an advanced age of patients and E. coli infections have been associated with poor QOL. The mortality rate increased in relation with the importance of excised body surface. In spite of the gravity of these infections, our patients were satisfied of their treatment.

Dealing with tattoos in plastic surgery. Tattoo removal.

Not only has tattooing been socially performed for thousands of years, but it has also been part and parcel of medical practice since antiquity. In our day and age, plastic surgeons are ever more frequently compelled to deal with tattooing - and with tattoo removal procedures, as well. While the process itself may appear harmless, it is not without risk and necessitates use of suitable tools and management by expert hands.

Medial thighplasty: Current concepts and practices.

Medial thighplasty, also known as medial thigh lift, is a procedure that has been carried out for five decades. The original "Lewis" technique has undergone many changes, and thereby been rendered widely available to plastic surgeons. Given the increasingly high number of surgical reconstructions after massive weight loss, this technique is now an integral part of a surgeon's therapeutic arsenal as he strives to meet the evolving demands of patients. The objective of this article, which is based on a comprehensive review of the literature, is to summarize current knowledge on medial thighplasty and thereby allow plastic surgeons to adopt the operating technique best suited to the deformations presented by their patients and to the overall context. The different techniques, outcomes and complications are successively discussed.

Zosteriform configuration of multiple eccrine spiradenomas of the scalp.

BACKGROUND: Eccrine spiradenoma (ES) is a benign adnexal tumor predominantly located in the head and neck regions. Multiple neoplasms located on the scalp have been reported but never with a zosteriform configuration on the first trigeminal area. CASE REPORT: We describe an original case report of a 75-year-old Caucasian man presenting multiple subcutaneous blue and purple nodules disseminated on the first left trigeminal dermatome. All the nodules appeared gradually on a one-year period. Biopsy revealed a nodular adnexal tumor in the dermis without malignant eccrine spiradenoma (MES) transformation. The surgical procedure was performed in a manner to protect the galea aponeurotica in the upper half on the first left trigeminal area. The frontalis muscle was raised with the surgical specimen in the lower half of the first trigeminal area. A split-thickness skin graft was applied on the surgical defect. Histological examination revealed multilobular well-defined tumors located in the dermis. CONCLUSION: The presence of multiple subcutaneous nodules in a trigeminal pattern should suggest a multiple localized zosteriform ES. The diagnosis is focused on clinical findings and the treatment is based on a large surgical excision. The histological examination is essential for not to fail a MES transformation.

[Changing and follow-up of silicone gel-filled breast implants: Multicentric, retrospective study about 130 rupture cases]. / Surveillance et changement des implants mammaires en gel de silicone: étude rétrospective a propos de 130 cas de rupture d'implants.

SUBJECT: A recent report from "Agence Nationale de sécurité du medicament et des produits de santé" (ANSM) assesses the rupture of silicone gel breast implants without proposing rules for follow-up and replacement of implants. OBJECTIVE: To demonstrate that systematic follow-up surveillance of silicone breast implants could improve early diagnosis of ruptures; to propose a surveillance protocol based on the findings. MATERIALS AND METHODS: This is a multicentric, retrospective study which reports cases of ruptured silicone gel breast implants from January 2006 to June 2014. Using Case-notes from ANSM and quotations from CCAM certificates, 130cases were gathered from 6 centers. RESULTS: The average time between implantation and the diagnosis of ruptures was 9.24 years (± 6.19). Forty cases of ruptured implants (30.8%) originated from original reconstruction or symmetrisation in the context of a breast carcinoma; and 90 (69.2%) originated from augmentation mammaplasty. The average length in reconstructive group was 6.97 years (± 3.33). The difference in the lifetime of the implants between both groups was statistically significant (P = 0.0291). A clinical abnormality led to an imaging assessment in only 19.7% of cases; rupture was thus mainly discovered incidentally either during a systematic breast screening (59.8%), or during a preoperative examination for an aesthetic surgery (20.5%) (P = 0.0082). CONCLUSIONS: The results suggest that implant ruptures of silicone gel breast implants are under diagnosed. Clinical follow-up seems insufficient to diagnose implant ruptures. Ultra sound surveillance (± MRI) could be proposed 4 years, 7 years and 10 years after the initial surgery. It does not seem appropriate to propose a systematic change of implant without the incidence of a rupture.

[Photography in plastic surgery: practices, uses and legislation]. / Photographies en chirurgie plastique: pratiques, usages et législation.

INTRODUCTION: Photography in plastic surgery is omnipresent. Through its various uses, it may present both ethical and forensic risks. The objective of this study is to analyze the use of medical photography by the plastic surgeon, the perception of this use by the patient, and consequence of such use. METHOD: A questionnaire about the use of medical photography was assessed to 629 plastic surgeons. A questionnaire was given to patients, about their perception of the use of photography by their surgeon. RESULTS: One hundred and seventy-six surgeon's questionnaires and 93 patient's questionnaires were analyzed. For 97.7% of the responding surgeons, the proportion of patients refusing to be photographed was less then 1/20. The objective of the photography was especially medicolegal for 62.5% of the surgeons, especially for following the patient progress (87.5%), partially for the formation (72.1%), partially for scientific publications (57.8%) and not at all for the personal publicity (73.1%). Surgeons often share his photographs with others surgeons (71.1%), sometimes with others medical personnel (48.8%). The security and the access to photographs were determined to be correct for 67.6% of the surgeons and perfect for 23.3%. In total, 17.2% of the surgeons obtained a written consent, 41.4% obtained an oral consent, and 38.5% did not request patient consent. It was found that 48.3% of the surgeons and 40.2% of the patients think that the right to the photographic images belong to the patient. CONCLUSION: Medical photographs expose the plastic surgeon to medico-legal risks. He must know and follow the law in order to prevent eventual legal proceedings.

Pilomatrix Carcinoma of the scalp. A case report and review of the literature.

INTRODUCTION: Pilomatrix Carcinoma (PC) is a rare and malignant dermo-hypodermic tumor. Only 11 cases were reported in patients younger than 18 years old and only 13 cases were reported on the scalp. CASE REPORT: We report the case of a 15-year-old woman who underwent cyst excision on the vertex. Anatomopathology shed light trichilemmal cyst. Five months later, she presented a first local recurrence. The tumor was removed with wide margin. Anatomopathology shed light PC. No adjuvant therapy was performed. The patient presented a second recurrence 3 months later with a parietal bone and superior sagittal sinus invasion and a lung metastasis. She underwent a craniotomy and radiochemotherapy. A third local recurrence was detected 4 months later. Three more lines of chemotherapy were performed without success. DISCUSSION: PC is a locally aggressive tumour, with a high rate of local recurrences and metastases. PC arises de novo or through malignant transformation of a pilomatrixoma. PC were observed frequently in the white male over 50 years old. The histological diagnosis is difficult to prove. Treatment consists of a wide surgical excision. Peritumoral margins are not codified. Because of most cases are on the face and neck, Mohs Micrographic Surgery seems to be a good modality to limit margins. Radiation therapy is an adjuvant treatment. Chemotherapy can be used in metastasis case. CONCLUSION: PC is a rare malignant tumor with high rate of disease relapse. Histological diagnosis is difficult and treatment is not standardized. Surgical procedure with wide margins is recommended to avoid the large recurrence when the staging shows no metastasis.

PAGAT gel dosimetry for everyone: gel production, measurement and evaluation.

Polymer gel (PG) dosimetry is a valuable tool to measure complex dose distributions in 3D with a high spatial resolution. However, due to complex protocols that need to be followed for in-house produced PGs and the high costs of commercially available gels, PG gels are only rarely applied in quality assurance procedures worldwide. In this work, we provide an introduction to perform highly standardized dosimetric PG experiments using PAGAT (PolyAcrylamide Gelatine gel fabricated at ATmospheric conditions) dosimetry gel. PAGAT gel can be produced at atmospheric conditions, at low costs and is evaluated using magnetic resonance imaging (MRI). The conduction of PG experiments is described in great detail including the gel production, treatment planning, irradiation, MRI evaluation and post-processing procedure. Furthermore, a plugin in an open source image processing tool for post-processing is provided free of charge that allows a standardized and reproducible analysis of PG experiments.

Development of phantom materials with independently adjustable CT- and MR-contrast at 0.35, 1.5 and 3 T.

Quality assurance in magnetic resonance (MR)-guided radiotherapy lacks anthropomorphic phantoms that represent tissue-equivalent imaging contrast in both computed tomography (CT) and MR imaging. In this study, we developed phantom materials with individually adjustable CT value as well as [Formula: see text]- and [Formula: see text]-relaxation times in MR imaging at three different magnetic field strengths. Additionally, their experimental stopping power ratio (SPR) for carbon ions was compared with predictions based on single- and dual-energy CT. Ni-DTPA doped agarose gels were used for individual adjustment of [Formula: see text] and [Formula: see text] at [Formula: see text] and 3.0 T. The CT value was varied by adding potassium chloride (KCl). By multiple linear regression, equations for the determination of agarose, Ni-DTPA and KCl concentrations for given [Formula: see text] [Formula: see text] and CT values were derived and employed to produce nine specific soft tissue samples. Experimental [Formula: see text] [Formula: see text] and CT values of these soft tissue samples were compared with predictions and additionally, carbon ion SPR obtained by range measurements were compared with predictions based on single- and dual-energy CT. The measured CT value, [Formula: see text] and [Formula: see text] of the produced soft tissue samples agreed very well with predictions based on the derived equations with mean deviations of less than [Formula: see text] While single-energy CT overestimates the measured SPR of the soft tissue samples, the dual-energy CT-based predictions showed a mean SPR deviation of only [Formula: see text] To conclude, anthropomorphic phantom materials with independently adjustable CT values as well as [Formula: see text] and [Formula: see text] relaxation times at three different magnetic field strengths were developed. The derived equations describe the material specific relaxation times and the CT value in dependence on agarose, Ni-DTPA and KCl concentrations as well as the chemical composition of the materials based on given [Formula: see text] and CT value. Dual-energy CT allows accurate prediction of the carbon ion range in these materials.

The accuracy of helium ion CT based particle therapy range prediction: an experimental study comparing different particle and x-ray CT modalities.

This work provides a quantitative assessment of helium ion CT (HeCT) for particle therapy treatment planning. For the first time, HeCT based range prediction accuracy in a heterogeneous tissue phantom is presented and compared to single-energy x-ray CT (SECT), dual-energy x-ray CT (DECT) and proton CT (pCT). HeCT and pCT scans were acquired using the US pCT collaboration prototype particle CT scanner at the Heidelberg Ion-Beam Therapy Center. SECT and DECT scans were done with a Siemens Somatom Definition Flash and converted to RSP. A Catphan CTP404 module was used to study the RSP accuracy of HeCT. A custom phantom of 20 cm diameter containing several tissue equivalent plastic cubes was used to assess the spatial resolution of HeCT and compare it to DECT. A clinically realistic heterogeneous tissue phantom was constructed using cranial slices from a pig head placed inside a cylindrical phantom (ø150 mm). A proton beam (84.67 mm range) depth-dose measurement was acquired using a stack of GafchromicTM EBT-XD films in a central dosimetry insert in the phantom. CT scans of the phantom were acquired with each modality, and proton depth-dose estimates were simulated based on the reconstructions. The RSP accuracy of HeCT for the plastic phantom was found to be 0.3 ± 0.1%. The spatial resolution for HeCT of the cube phantom was 5.9 ± 0.4 lp cm-1for central, and 7.6 ± 0.8 lp cm-1for peripheral cubes, comparable to DECT spatial resolution (7.7 ± 0.3 lp cm-1and 7.4 ± 0.2 lp cm-1, respectively). For the pig head, HeCT, SECT, DECT and pCT predicted range accuracy was 0.25%, -1.40%, -0.45% and 0.39%, respectively. In this study, HeCT acquired with a prototype system showed potential for particle therapy treatment planning, offering RSP accuracy, spatial resolution, and range prediction accuracy comparable to that achieved with a commercial DECT scanner. Still, technical improvements of HeCT are needed to enable clinical implementation.

Compatibility of 3D printing materials and printing techniques with PAGAT gel dosimetry.

Polymer gel (PG) dosimetry enables three dimensional (3D) measurement of complex dose distributions. However, PGs are strongly reactive with oxygen and other contaminations, limiting their applicability by the need to use specific container materials. We investigate different 3D printing materials and printing techniques for their compatibility with PG. Suitable 3D printing materials may provide the possibility to perform PG dosimetry in complex-shaped phantoms. 3D printed and PG-filled test vials were irradiated homogenously. The signal response was evaluated with respect to homogeneity and compared to the signal in already validated reference vials. In addition, for the printing material VeroClear™ (StrataSys, Eden Prairie, USA) different methods to remove support material, which was required during the printing process, were investigated. We found that the support material should be used only on the outer side of the container wall with no direct contact to the PG. With the VeroClear™ material a homogenous signal response was achieved with a mean deviation of [Formula: see text] relative to the reference vials. In addition, the homogeneous irradiation of an irregularly-shaped gel container designed with the same printing material and technique also lead to a homogenous PG response. Furthermore, a small field irradiation of an additional test-vial showed an accurate representation of steep dose gradients with a deviation of the maximum position of [Formula: see text] relative to the reference vial.

End-to-end test of an online adaptive treatment procedure in MR-guided radiotherapy using a phantom with anthropomorphic structures.

Online adaptive treatment procedures in magnetic resonance (MR)-guided radiotherapy (MRgRT) allow compensating for inter-fractional anatomical variations in the patient. Clinical implementation of these procedures, however, requires specific end-to-end tests to validate the treatment chain including imaging, treatment planning, positioning, treatment plan adaption and accurate dose delivery. For this purpose, a new phantom with reproducibly adjustable anthropomorphic structures has been developed. These structures can be filled either with contrast materials providing anthropomorphic image contrast in MR and CT or with polymer dosimetry gel (PG) allowing for 3D dose measurements. To test an adaptive workflow at a 0.35 T MR-Linac, the phantom was employed in two settings simulating inter-fractional anatomical variations within the patient. The settings included two PG-filled structures representing a tumour and an adjacent organ at risk (OAR) as well as five additional structures. After generating a treatment plan, three irradiation experiments were performed: (i) delivering the treatment plan to the phantom in reference setting, (ii) delivering the treatment plan after changing the phantom to a displaced setting without adaption, and (iii) adapting the treatment plan online to the new setting and delivering it to the phantom. PG measurements revealed a homogeneous tumour coverage and OAR sparing for experiment (i) and a significant under-dosage in the PTV (down to 45% of the prescribed dose) and over-dosage in the OAR (up to 180% relative to the planned dose) in experiment (ii). In experiment (iii), a uniform dose in the PTV and a significantly reduced dose in the OAR was obtained, well-comparable to that of experiment (i) where no adaption of the treatment plan was necessary. PG measurements were well comparable with the corresponding treatment plan in all irradiation experiments. The developed phantom can be used to perform end-to-end tests of online adaptive treatment procedures at MR-Linac devices before introducing them to patients.