Skin Markers Research Articles

Daily Dosimetric Robustness of Prone-Position Whole Breast Radiotherapy (WBRT) Planned With Electronic Tissue Compensation (ECOMP) and 6MV Flattening Filter Free (6X-FFF) Beam Energy: Dose Variation and Predictive Factors

This study investigates daily dose to prone-positioned patients undergoing tangential WBRT on an O-ring LINAC with 6X-FFF energy. For prone breast patients, most practices rely on skin marks or daily planar image matching. This system provides low dose (<1mGy CTDIvol) daily CBCT, which was used to verify daily robustness of target coverage and hotspot dose metrics for prone-position WBRT. Eight patients treated with 16-fraction prone breast WBRT planned with ECOMP were retroactively studied. During treatment, patients were positioned under CBCT guidance by matching to the chest wall. Planning CTs were deformed to daily CBCT to generate daily synthetic CTs, on which daily dose distributions were calculated. A total of 8 patients x 16 fractions = 128 synthetic CTs were generated. Consensus ASTRO definition was used to contour Breast PTV Eval for each daily deformed CT. Target coverage (V90%) and hotspot (V105%) to Breast PTV Eval contour was monitored each day. Various predictors (patient weight, breast separation, breast deformation / dice similarity coefficient DSC, etc.) were fit into a mixed effect linear regression model predicting V90% and V105% deviation from planned values (ΔV90%, ΔV105%). Statistical significance is indicated with asterisks (* for p<0.05; ** for p<0.001). For all synthetic CTs studied, V90% (as % of Breast PTV Eval volume) was moderately smaller than planned (median ΔV90% = -0.1%*), while V105% was much larger (median ΔV105% = +10.1%** or +92.4cc**). Among all fractions studied, only 40% met PTV Breast Eval V105%<15% criteria and 59% met V90%>95%. V90% and V105% did not correlate with time. Breast PTV Eval volume decreased with time (-2.21cc per fx*), possibly indicating general weight loss or seroma resolution. Patient’s weight loss correlated with significantly increased V105% (+4.6% / -1% weight., R = 0.4**) and moderately decreased V90% (-0.071% / -1% wt., R = 0.2**). However, comprehensive models indicate three factors influence ΔV90% and ΔV105% the most (with R = 0.86**, 0.95** respectively): (1) Breast separation decrease (-0.09%* and +10%** per -1cm), (2) PTV Eval volume decrease (-0.4%** and +9%** per -100cc), and for ΔV105% only, (3) more breast deformation (+10%** per -1% ΔDSC). For patients undergoing tangential prone breast WBRT with ECOMP-planned parallel opposed beams, daily CBCT revealed key dosimetric parameters vary significantly, especially for V105% associated with negative cosmesis. Patient weight loss substantially increased hotspots and slightly decreased coverage over treatment course. Breast separation and shape changes could be used to predict dosimetric variations. Preliminary findings suggest some patients could benefit from an adaptive plan based on daily CBCT.

VENUS SHELL: Personalized 3D Printed Breast Shells for Prone Breast Radiotherapy

Patients report that the dedicated boards used in prone breast treatment are uncomfortable. In practice it is also difficult to reproducibly align the patient in prone, requiring time and repeated imaging to properly position the patient. In this study we investigate the idea of using personalized, 3D printed, breast shells to transform the breast board into a personalized device with the aim to improve patient comfort and reduce positioning time and inaccuracy. A healthy volunteer was put in treatment position on top of a modified dedicated breast board using movable, plexiglass, transparent, body-shaper elements to shape the body as wanted. A 3D surface model of the volunteer was then acquired using a high-resolution surface scanner. Using CAD software two different shell models that attach to the treatment board were created. The first model was 3D printed in PLA and the second both in PLA and PET-G. The volunteer self-positioned herself repeatedly in treatment position without feedback from an external operator. Cranial, medial and caudal skin marks were made on the volunteer’s back and thorax. Reproducibility of body position with respect to reference marks made on the shells was measured 5 times per shell using the in-room laser and a ruler with mm graduation. The first position was taken as reference position. Time to self-align from sitting on the board to treatment position was measured and categorized as longer or shorter than 1 minute. Comfort with and without shell was simply reported by the volunteer. Comfort increased with both shell models even while testing over a 40 minutes period. Time to align and position reproducibility depended on the shell model, but not on the shell material. Self-positioning within the shell reproduced the body position with a mean ± standard deviation of 5 ± 3 mm for the 1st shell model but which required more than 1 minute for volunteer to find a comfortable fit. The 2nd model allowed to self-align within 1 minute and had good position accuracy of 2 ± 2 mm. Personalized, 3D printed, breast shells could help improve patient comfort in prone position and obtain a patient pre-positioning accuracy of a few millimeters within 1 minute. Because the shell material is MRI compatible, it is possible to do MRI prone simulation and diagnostic in final treatment position. A clinical trial is currently in preparation and will soon verify if these results can be reproduced on a population of real breast cancer patients.

Fluoroscopy-based subject-specific knee joint constraints for the estimation of prosthesis kinematics and contact velocities during gait

Estimation of the kinematics of the natural or prosthetic knee joint from skin markers is challenging due to soft tissue artefact (Camomilla et al. 2017). A solution can be to perform a multibody k...

Daily heroin injection and psychiatric disorders: A cross-sectional survey among People Who Inject Drugs (PWID) in Haiphong, Vietnam

BackgroundPsychiatric comorbidities are frequent among people who inject drugs, they are associated with a poorer prognosis and need to be addressed. Their interaction with daily heroin injection requires clarification. MethodsA cross-sectional survey was conducted among PWID recruited in the city of Haiphong, Vietnam, by respondent-driven sampling. The inclusion criteria were age 18 or older and current injection drug use, verified by skin marks and positive urine tests for heroin or methamphetamine. Data on socio-demographic characteristics, drug use, sexual behaviour and access to treatment were collected using face-to-face questionnaires by trained interviewers. PWID were screened by trained psychiatrists for depression, psychotic disorder and suicidality, using the MINI questionnaire. Results418 participants were included in the analyses. All were injected heroin users, 21 % were diagnosed with a current major depressive disorder, 15 % with a current psychotic disorder and 12 % presented a suicide risk. In the bivariate analyses, regular meth use, cannabis use and ketamine use were positively associated with presenting at least one psychiatric condition while daily heroin injection and being currently treated with methadone were negatively associated. In the multivariate model, poly-substance use was positively associated with depression (methamphetamine and drinking in addition to heroin) and psychotic disorder (methamphetamine and/or hazardous drinking in addition to heroin) while daily heroin injection and current methadone treatment were negatively and independently associated with depression and psychotic syndrome. ConclusionsOur survey confirms the burden of methamphetamine use and the protective effect of methadone but also a possible protective effect of daily heroin injection.

Institut Curie guidelines on breast target volume delineation for patients treated in lateral position

PurposeTo develop guidelines for and describe the delineation of breast for patients treated in lateral position and to transform this three-dimensional technique based on the virtual simulation to volume-based modern intensity-modulated irradiation technique. Material and methodsIn our department, during the daily delineation, radiation oncologists specialized in breast cancer treatment sought consensus on the delineation of clinical treatment volume of the breast through dialogue based on cases. A radiation oncologist delineated clinical treatment volumes on CT scans of five to 20 patients, followed by a discussion and adaptation of the delineation between all radiation oncologists of the team. The consensus established between clinicians was discussed, corrected and improved. All patients were delineated in treatment position; skin markers were used to visualize the breast tissue after careful palpation. ResultsBreast clinical treatment volume was situated and delineated between pectoral muscle and 5mm below the skin (dosimetric considerations), within the space outlined by skin markers, that showed the limits of the palpable breast tissue. In lateral position some vessels were very useful to define the limits as rami mammarii (from thoracica interna) for the internal one and thoracica lateralis for the external. This is the first atlas proposed for the delineation of the breast clinical treatment volumes for breast cancer using alternative technique of breast irradiation (lateral). ConclusionThis atlas will be helpful for the volume definition in our daily practice of breast irradiation in lateral position and can open perspectives to develop also atlases for other alternative techniques as treatment in prone position.

Clinical and dermoscopic features of Fibroepithelioma of Pinkus: case series with an emphasis on hypopigmented to pink lines intersecting at acute angles.

Fibroepithelioma of Pinkus (FEP) is a subtype of basal cell carcinoma (BCC) that can clinically resemble intradermal nevi (IDN) and fibromas. We performed a retrospective review of consecutively biopsied lesions confirmed to be FEP on histopathology diagnosed from January 1, 2008 to April 8, 2019. Clinical (n = 48), contact non-polarized dermoscopy (NPD) (n = 44), and contact polarized dermoscopy (PD) (n = 22) images from 36 patients were reviewed. Mean age was 64.5years (SD 15.1years, range 24-86years) at diagnosis of first FEP lesion. Most lesions were located on the torso (n = 28, 58.3%), followed by the lower extremity (n = 9, 18.8%). The most common differential diagnoses at the time of biopsy included BCC (n = 40) and nevus (other than IDN, n = 5). Clinically, FEP were pink (95.8%), scaly (66.7%) papules (77.1%) displaying disrupted skin markings (62.5%) and absence of hair follicles (87.5%). NPD revealed serpentine (97.7%), dotted (81.8%), or polymorphous vessels (86.4%), and hypopigmented to pink lines intersecting at acute angles (HPLA) (52.3%). PD demonstrated serpentine (95.5%), dotted (86.4%), or polymorphous vessels (81.8%), shiny white lines (50.0%), and HPLA (59.1%). Classic features of BCC such as arborizing vessels (n = 2), ulceration (n = 1), shiny white blotches and strands (n = 1), blue-gray ovoid nest (n = 1), and leaf-like areas (n = 1) were uncommon. FEP often presents as scaly, erythematous papules with disrupted skin markings and absence of hair follicles. Dermoscopy reveals polymorphous vessels with shiny white lines and HPLA.

Application of Henna as a Durable Skin Marker in Orthopedic Surgery.

BackgroundMany orthopedic procedures require skin marking well before surgery. Marks made with most conventional marking pens fade with vigorous skin preparation required before orthopedic procedures, whereas marks with henna may safely last almost up to three weeks. Thereby, we intend to describe applications of henna, a readily available, cost-effective material, as a durable skin marker for various indications in orthopedics.MethodsA total of 120 patients with varied indications for skin marking were randomized into two equal-sized groups of 60 each. Group A patients were marked with henna and group B patients with a permanent skin marker before the intended surgery. All patients had a routine pre-operative bath one day before surgery and vigorous skin preparation using chlorhexidine and ethanol-based scrubs just before surgery in the operating room. The two markers were compared for the following variables: photographic record to determine fading of the mark after scrubbing, in terms of successful execution of the procedure, patients’ acceptability of the mark, any allergy or infection, and final time of disappearance of the mark.ResultsMarking with henna was clearly visible during all but one surgical procedure even after vigorous pre-operative skin preparation, thereby ensuring minimal use of fluoroscopy in henna-marked patients. The fading of the mark and use of fluoroscopy was significantly low in group A (p<0.05). There was no complication associated with marking with either marking method. Marks with henna disappeared on an average nine days later than with permanent marker. In terms of acceptability of mark, henna was preferred by almost all patients.ConclusionsHenna paste is an ideal substance for use as a skin marker in conditions, such as foreign body removal, vertebral level identification, nail dynamization, marking tibial physis in children, and sequestrum in non-discharging osteomyelitis, and in marking blood vessel course in tumor surgery or in volar ganglion removal. Pre-operative skin marking with henna ensures minimal use of fluoroscopy, and it is particularly efficacious when ultrasound is used for localization as it can be directly applied over gel film.

How to do safe intracorporeal marking of structures during minimally invasive surgery by simple modification of a skin marking pen.

This study describes how to do safe intracorporeal marking of structures during minimally invasive surgery by simple modification of a skin marking pen. We wish to publicize the use of a skin marking pen tip held within laparoscopic graspers as an effective, simple and cheap method to mark intracorporeal structures, avoiding tissue damage.

Skin transcriptome, tissue distribution of mucin genes and discovery of simple sequence repeats in crucian carp (Carassius auratus).

Crucian carp (Carassius auratus) is one of the major freshwater species and important food fish in China. Fish skin acts as the first line of defence against pathogens, yet its molecular and immune mechanism remains unclear. In this study, a de novo transcriptome assembly of C. auratus skin was performed with the Illumina Hiseq 2000 platform. A total of 49,154,776 clean reads were assembled, among which 60,824 (46.86%), 37,103 (28.59%), 43,269 (33.33%) unigenes were annotated against National Center for Biotechnology Information, Gene Onotology and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, respectively. KEGG Orthology categories were significantly involved in immune system (20.50%), signal transduction (18.04%) and mucosal mucin genes (e.g., muc2, muc5AC, muc5B, muc17, muc18). The high expression of muc18 gene was observed in brain; that of muc2 in intestine; and that of muc5AC in skin, liver, spleen, intestine and muscle. Moreover, the potential 28,928 simple sequence repeats with the three most abundant dinucleotide repeat motifs (AC/GT, AG/CT, AT/AT) were detected in C. auratus. To authors' knowledge, this is the first report to describe the transcriptome analysis of C. auratus skin, and the outcome of this study contributed to the understanding of mucosal immune response of the skin and molecular markers in cyprinid species.

Clinically Relevant Vulnerabilities of Deep Machine Learning Systems for Skin Cancer Diagnosis

Clinically Relevant Vulnerabilities of Deep Machine Learning Systems for Skin Cancer Diagnosis

Mitochondrial Oxygen Monitoring During Surgical Repair of Congenital Diaphragmatic Hernia or Esophageal Atresia: A Feasibility Study.

Current monitoring techniques in neonates lack sensitivity for hypoxia at cellular level. The recent introduction of the non-invasive Cellular Oxygen METabolism (COMET) monitor enables measuring in vivo mitochondrial oxygen tension (mitoPO2), based on oxygen-dependent quenching of delayed fluorescence of 5-aminolevulinic acid (ALA)-enhanced protoporphyrin IX. The aim is to determine the feasibility and safety of non-invasive mitoPO2 monitoring in surgical newborns. MitoPO2 measurements were conducted in a tertiary pediatric center during surgical repair of congenital diaphragmatic hernia or esophageal atresia. Intraoperative mitoPO2 monitoring was performed with a COMET monitor in 11 congenital diaphragmatic hernia and four esophageal atresia neonates with the median age at surgery being 2 days (IQR 1.25–5.75). Measurements were done at the skin and oxygen-dependent delayed fluorescence was measurable after at least 4 h application of an ALA plaster. Pathophysiological disturbances led to perturbations in mitoPO2 and were not observed with standard monitoring modalities. The technique did not cause damage to the skin, and seemed safe in this respect in all patients, and in 12 cases intraoperative monitoring was successfully completed. Some external and potentially preventable factors—the measurement site being exposed to the disinfectant chlorohexidine, purple skin marker, or infrared light—seemed responsible for the inability to detect an adequate delayed fluorescence signal. In conclusion, this is the first study showing it is possible to measure mitoPO2 in neonates and that the cutaneous administration of ALA to neonates in the described situation can be safely applied. Preliminary data suggests that mitoPO2 in neonates responds to perturbations in physiological status.

Is there a risk for bacterial transmission from surgical marker pens?

Markers for preoperative skin marking are used several times and bear a risk of transmitting bacteria. Bacterial contamination was assessed by sonication and culture. Antimicrobial susceptibility testing (AST) was performed for facultative pathogens to assess multi-drug resistance (MDR). An accelerated failure time model was applied to assess the statistical relationship between the bacterial contamination and the filling status of markers. Of 45 markers, 13 had a colony count <10 cfu/mL and 32 had counts from 10 to 12,500 cfu/mL. Three markers were colonized by Staphylococcus aureus. No MDR bacteria were found. We recommend single use of markers to reduce transmission risk.

A marking of the cricothyroid membrane with extended neck returns to correct position after neck manipulation and repositioning.

Emergency front of neck airway access by anaesthetists carries a high failure rate and it is recommended to identify the cricothyroid membrane before induction of anaesthesia in patients with a predicted difficult airway. We have investigated whether a marking of the cricothyroid membrane done in the extended neck position remains correct after the patient's neck has been manipulated and subsequently repositioned. The subject was first placed in the extended head and neck position and had the cricothyroid membrane identified and marked with 3 methods, palpation, 'laryngeal handshake' and ultrasonography and the distance from the suprasternal notch to the cricothyroid membrane was measured. The subject then moved off the table and sat on a chair and subsequently returned to the extended neck position and examinations were repeated. Skin markings of all 11 subjects lay within the boundaries of the cricothyroid membrane when the subject was repositioned back to the extended neck position and the median difference between the two measurements of the distance from the suprasternal notch was 0mm (range 0-2mm). The cricothyroid membrane can be identified and marked with the subject in the extended neck position. Then the patient's position can be changed as needed, for example to the 'sniffing' neck position for conventional intubation. If a front of neck airway access is required during subsequent airway management, the patient can be returned expediently to the extended-neck position, and the marking of the centre of the membrane will still be in the correct place.

A Rump‐mount Harness Design Improvement for Greater Sage‐grouse

ABSTRACTMarking birds with radiotransmitters to ascertain movements and demographic parameters has been a common practice for &gt;50 years. Previous research provides evidence that transmitters may negatively affect some avian species, including gallinaceous birds. Investigators now commonly use rump‐mount transmitters with leg‐loop harnesses to monitor greater sage‐grouse (Centrocercus urophasianus), but there is concern about effects of such harnesses with no published protocols for harness construction or attachment. During spring 2017–2019, we captured male greater sage‐grouse on or near strutting grounds in Moffat County, Colorado, USA. In 2017, we deployed 20 very‐high‐frequency transmitters on male greater sage‐grouse with elasticized Teflon™‐ribbon harnesses, but discovered marked birds sustained skin abrasions and lacerations. After this discovery, we modified the harness to use ribbon sheathed with tubing. We used the modified harness on 129 males in 2018 and 2019. We found few to no abrasions or lacerations on 8 out of 8 recaptured males with the modified harness, whereas only 1 out of 7 recaptured males fitted with the original elasticized ribbon harness had few to no abrasions or lacerations. Our findings suggest that sheathing the ribbon used to build the leg loops improves the commonly used elasticized‐ribbon design. We suggest investigators planning to use rump‐mount harnesses on male and female greater sage‐grouse to consider adopting our design, develop and test a new or improved design, and carefully consider harness materials, construction, and fit prior to deployment. © 2020 The Wildlife Society.

Reliable Method of Radial and Ulnar Nerve Identification During the Posterior Approach to the Humerus: A Clinical and Cadaveric Correlation Study.

To determine the reliability of using "fingerbreadths" and anatomic landmarks as reference points for predictable identification of the radial and ulnar nerves when using the posterior approach to the humerus. A systematic approach using "fingerbreadths" to mark and measure the skin before incision. Two markings were made: the first 4 fingerbreadths proximal to the lateral epicondyle (radial nerve location) and the second 2 fingerbreadths proximal to the medial epicondyle (ulnar nerve location). Once the posterior approach was made, the same fingerbreadths were used on the radial and ulnar sides to identify the radial and ulnar nerves within the deep interval. Measurements were taken at each stage in cadaveric specimens. Clinical correlations followed. Statistical analysis was performed comparing measurements (outer vs. inner) in both cadaveric and clinical specimens. Thirty-two elbows evaluated in this study, 20 patients and 12 cadaveric specimens. In the cadaveric specimens, the mean distance of the radial nerve was 7.59 cm from the lateral epicondyle, SD ± 0.17 cm (P = 0.55), and the ulnar 3.68 cm from medial epicondyle, SD ± 0.63 cm (P = 0.302). In the clinical measurements, the radial nerve was 7.46 cm, SD ± 0.48 cm, never within 7.0 cm (P = 0.425), and the ulnar nerve was 3.14 cm, SD ± 0.31 cm (P = 0.051). Statistical analysis yielded no difference between skin marking and actual location in the deep interval, between cadaveric and clinical specimens, observer fingerbreadth widths, or between left or right arms. Use of "fingerbreadths" is a reliable, efficient, and reproducible method of identifying both the radial and ulnar nerves during the posterior approach to the humerus.

CORRELATION BETWEEN WEIGHT OF SPECTACLE AND THE CONTACT AREA OF NOSE PADS WITH RESPECT TO STANDARD ALIGNMENT

Aim: To understand the co-relation between the weight of spectacle and the contact area of nose pads with respect to standard alignment. Study Design: A cross-sectional study. Method: Parameters such as weight of spectacle, frontal angle of nose and nose pads, splay angle of nose and nose pads and pantoscopic angle, area of nose pads and contact area of nose pads were measured using simple tools such as portable weighing machine and a handmade gauge similar to Fairbanks facial gauge and the correlation between all the parameters was found out. Results: Out of total 75 frames, 42 frames (56%) had no change in contact area with the corresponding area of nose pads with respect to the parameters including weight of spectacle frontal angle, splay angle and pantoscopic angle in standard alignment of spectacle, while other 33 frames (44%) had a noticeable change in the contact area of nose pads with respect to the corresponding parameters. Conclusion: Difference of 50mm2 of area between contact area and area of nose pads is ac-ceptable with current trend of frames. Current trend of light weight frames and lenses has given ease to alignment as even misalignment does not result into marks. Contact area corresponding with the area of nose pad play a significant role in distribution of spectacle weight on nose. Mismatch between contact area and area of nose pads will result into skin marks. Ideally, a wearer is happy when standard alignment is achieved with respect to facial measurements.

Frameless Patient Tracking With Adhesive Optical Skin Markers for Augmented Reality Surgical Navigation in Spine Surgery

Observational study. The aim of this study was to evaluate the accuracy of a new frameless reference marker system for patient tracking by analyzing the effect of vertebral position within the surgical field. Most modern navigation systems for spine surgery rely on a dynamic reference frame attached to a vertebra for tracking the patient. This solution has the drawback of being bulky and obstructing the surgical field, while requiring that the dynamic reference frame is moved between vertebras to maintain accuracy. An augmented reality surgical navigation (ARSN) system with intraoperative cone beam computed tomography (CBCT) capability was installed in a hybrid operating room. The ARSN system used input from four video cameras for tracking adhesive skin markers placed around the surgical field. The frameless reference marker system was evaluated first in four human cadavers, and then in 20 patients undergoing navigated spine surgery. In each CBCT, the impact of vertebral position in the surgical field on technical accuracy was analyzed. The technical accuracy of the inserted pedicle devices was determined by measuring the distance between the planned position and the placed pedicle device, at the bone entry point. The overall mean technical accuracy was 1.65 ± 1.24 mm at the bone entry point (n = 366). There was no statistically significant difference in technical accuracy between levels within CBCTs (P ≥ 0.12 for all comparisons). Linear regressions showed that null- to negligible parts of the effect on technical accuracy could be explained by the number of absolute levels away from the index vertebrae (r ≤ 0.007 for all, β ≤ 0.071 for all). The frameless reference marker system based on adhesive skin markers is unobtrusive and affords the ARSN system a high accuracy throughout the navigated surgical field, independent of vertebral position. 3.

Rapid prototyping of custom radiocontrast agent markers for computed tomography-guided procedures.

The objective of this study was to evaluate a method for printing a custom radiocontrast agent mixture to develop computed tomography markers of various shapes and sizes for assisting physicians in computed tomography-guided procedures. The radiocontrast agent mixture was designed to be bright in a computed tomography image, able to be extruded from a nozzle as a liquid and transition into a solid, and sufficiently viscous to be extruded through the tip of a needle in a controlled manner. A mixture printing method was developed using a syringe to house the mixture, a syringe pump to extrude the mixture, and a computer numeric control laser cutter to direct the nozzle in the desired path. To assess the efficacy of printing the radiocontrast agent mixture, we printed several designs, collected computed tomography images, and evaluated various physical properties of the printing method and the resulting computed tomography markers. The average line thickness was 1.56 mm (standard deviation of 0.19 mm, n = 30), the infill percentage was 99.9%, and the deviation in roundness was 0.23 mm (n = 30). These results demonstrated the ability of the proposed method to create various types of skin markers, such as dots, lines, and hollow or solid shapes. Additionally, flat printed patterns can be folded to form three-dimensional structures that can be used to guide and support needle insertions.

Techniques to verify the correct skin areas for biopsy, treatment, recurrence and in-vivo dosimetry using an A4 plastic sheet as template

Introduction Radiotherapy (RT) is a precise treatment usually given over multiple sessions with millimetre accuracy to the planned target. Patients undergoing RT require verification of the target area prior each treatment. Imaging with kilovoltage X-rays is usually used to verify the treatment volumes of solid internal tumours, but this process is unsuitable for skin cancers as it cannot visualise skin marks. When biopsying or treating skin cancers, there is a chance that other nearby benign skin structures can be confused with the lesion of concern. Templates using transparent sheets have been used to verify the treatment area. We present a series of cases to demonstrate our skin cancer verification technique using the humble A4 plastic sheet protector. Case series: Case 1 details the use of a plastic sheet template to correctly identify lesions that require biopsy. Cases 2 and 3 describe how templates are used for in-field verification prior to electron and superficial RT treatment, respectively. Case 4 shows how stored templates can be used to quantify recurrence. Conclusion: For skin cancer planning and verification, the A4 plastic sheet protector is easy to use, reproducible, economical and storable. It serves multiple purposes: to delineate areas of biopsy and treatment, to discover whether a recurrence is in-field or not, and to also verify where in vivo dosimetry should be measured.

Defining dose constraints for catheter insertion sites to minimize toxicity after interstitial breast brachytherapy

PurposeThe purpose of this study was to define dose constraints for catheter insertion sites to minimize probability of prominent post-therapy skin marks after interstitial breast brachytherapy. Methods and MaterialsForty patients who had undergone interstitial breast brachytherapy were studied at followup at least 2 years after the procedure. Their implant marks were compared with background skin and areola and scored as Gr0 = invisible (same color as surrounding skin), Gr1 = darker than surrounding skin but lighter than areola or hypopigmentation, and Gr2 = same color as areola or darker. Highest point doses received in each plane of implant and their corresponding closest distances from clinical target volume, 85% isodose, and closest catheter dwell point were used for analysis. A logistic regression was performed to ascertain effects of various dosimetric parameters on the probability of Gr2 marks. Receiver operating characteristic curve was generated to derive cutoffs. ResultsA total of 280 dose points were studied. Median values for various parameters were 1.4 Gy (0.24–3.74) for Dose max and 1.6 cm, 1.5 cm, and 1.0 cm for Dist CTV min, Dist Iso min, and Dist Dwell min, respectively. On logistic regression, increasing Dose max alone was associated with an increased likelihood of developing Gr2 marks. Each unit increase of Dose max increased probability of development of Gr2 skin marks by 5.0% (2.391–10.328). Receiver operating characteristic analysis also showed greatest odd ratio (8.0), sensitivity (74.8%), and specificity (73%) for Dose max. ConclusionsIt seems prudent to restrict dose to catheter insertion sites for better cosmesis.