A Free, Open-Source Toolkit to Produce 3D Bolus in the Clinic

PURPOSE/OBJECTIVE(S)

Tissue-equivalent, tissue-approximating and tissue-replacing bolus materials have been in use for decades in radiotherapy. Most frequently these materials are applied to a patient's skin to bring the highest dose region towards the surface of the skin-which is the location of the target. These materials can be applied at the time of simulation and included in a planning CT scan, or can be added during the planning process and first physically applied at the time of treatment. One of the most widely adopted materials for bolus has been sheets of a commercially available proprietary synthetic gel, which is uniform in thickness, and has some ability to match the curvature of the patient's body. Recently investigators have worked to create boluses using 3D printing technology, including several commercially available offerings. We hypothesized that we could create a bespoke, 3D bolus solution, using a series of open-source and free software products.

MATERIALS/METHODS

For an anthropomorphic phantom, a radiation treatment plan representative of skin cancer treatment was designed, this included a superficial target. The DICOM CT and structure set were imported into 3D Slicer, which is a free, open-source software for visualization, processing, segmentation, and registration. Using 3D Slicer, the bolus structure was saved as an STL file. Meshmixer, a free software for working with triangle meshes, was used to complete a mold design, and the mold parts were then printed using a rigid filament on a 3D printer. The mold parts were glued together, and small spring clamps were used secure the walls to the shells to ensure mold integrity. The mold was then filled with a thinned and degassed silicone. After appropriate curing, demolding was completed by removing the clamps and separating the walls. After QA, the bolus was applied to the anthropomorphic phantom and CTs were taken to compare a commercial sheet bolus with the in-house 3D printed product.

RESULTS

The bolus made via the in-house 3D printing process fit even complicated patient geometries well, and had both an obvious visual/goodness of fit advantage over the commercial sheet bolus and a nuanced dosimetric improvement as the air gaps present in the commercial sheet bolus were not desirable nor reproducible. The overall in-house workflow was efficient, and clinically reasonable (an estimated time of 72 hours was presented to the physician team, but in testing less than 24 hours was needed from export to delivery of the finished product).

CONCLUSION

In this work we explored whether motivated groups and departments could produce dosimetrically accurate and clinically reasonable custom boluses for patients undergoing radiotherapy to a superficial area of the body, using a test case on an anthropomorphic phantom. We found that this was absolutely achievable and could be implemented with no funds spent on software or licenses. Provided that a 3D printer, filament and silicone are available, any thoughtful practice can join the bespoke-bolus-club.

The Effects of Internet-Based Cognitive Behavioral Therapy for Suicidal Ideation or Behaviors on Depression, Anxiety, and Hopelessness in Individuals With Suicidal Ideation: Systematic Review and Meta-Analysis of Individual Participant Data

BACKGROUND

Suicide is a global public health problem. Digital interventions are considered a low-threshold treatment option for people with suicidal ideation or behaviors. Internet-based cognitive behavioral therapy (iCBT) targeting suicidal ideation has demonstrated effectiveness in reducing suicidal ideation. However, suicidal ideation often is related to additional mental health problems, which should be addressed for optimal care. Yet, the effects of iCBT on related symptoms, such as depression, anxiety, and hopelessness, remain unclear.

OBJECTIVE

We aimed to analyze whether digital interventions targeting suicidal ideation had an effect on related mental health symptoms (depression, anxiety, and hopelessness).

METHODS

We systematically searched CENTRAL, PsycInfo, Embase, and PubMed for randomized controlled trials that investigated guided or unguided iCBT for suicidal ideation or behaviors. Participants reporting baseline suicidal ideation were eligible. Individual participant data (IPD) were collected from eligible trials. We conducted a 1-stage IPD meta-analysis on the effects on depression, anxiety, and hopelessness-analyzed as 2 indices: symptom severity and treatment response.

RESULTS

We included IPD from 8 out of 9 eligible trials comprising 1980 participants with suicidal ideation. iCBT was associated with significant reductions in depression severity (b=-0.17; 95% CI -0.25 to -0.09; P<.001) and higher treatment response (ie, 50% reduction of depressive symptoms; b=0.36; 95% CI 0.12-0.60; P=.008) after treatment. We did not find significant effects on anxiety and hopelessness.

CONCLUSIONS

iCBT for people with suicidal ideation revealed significant effects on depression outcomes but only minor or no effects on anxiety and hopelessness. Therefore, individuals with comorbid symptoms of anxiety or hopelessness may require additional treatment components to optimize care. Studies that monitor symptoms with higher temporal resolution and consider a broader spectrum of factors influencing suicidal ideation are needed to understand the complex interaction of suicidality and related mental health symptoms.

The incremental validity of borderline personality disorder relative to major depressive disorder for suicidal ideation and deliberate self-harm in adolescents

Few studies have examined the relation between suicide-related behaviors and Borderline Personality Disorder (BPD) in adolescent samples. The current study investigated the incremental validity of BPD relative to Major Depressive Disorder (MDD) for suicide-related behaviors in a psychiatric sample of adolescents at the cross-sectional level of analysis. The sample included N = 156 consecutive admissions (55.1% female; M age = 15.47; SD = 1.41), to the adolescent treatment program of an inpatient treatment facility. Of the sample 19.2% (n = 30) met criteria for BPD on the Child Interview for DSM-IV Borderline Personality Disorder and 39.1% (n = 61) met criteria for MDD on the Computerized Diagnostic Interview Schedule for Children-IV. Results showed that BPD conferred additional risk for suicidal ideation and deliberate self-harm. Our findings support the clinical impression that BPD should be evaluated in inpatient samples of adolescents either through intake interviews or more structured assessments.

A statewide quality improvement collaborative to reduce neonatal central line-associated blood stream infections

OBJECTIVE

The objective of this study was to reduce central line-associated blood stream infections (CLABSIs) among 13 collaborating regional neonatal intensive care units by 25%. We tested the hypothesis that change could be attributed to the quality improvement collaborative by testing for 'special cause' variation.

STUDY DESIGN

Our prevention project included five features: (1) leadership commitment, (2) potentially best practices, (3) collaborative processes, (4) audit and feedback tools and (5) quality improvement techniques. Baseline (1 January 2006 to 30 August 2006) data were compared with the intervention (1 September 2006 to 30 June 2007) and post-intervention (1 July 2007 to 30 December 2007) periods and analyzed using statistical process control (SPC) methods.

RESULT

We detected special cause variation, suggesting that the collaborative was associated with reduced infection rates, from 4.32 to 3.22 per 1000 line days (a 25% decrease) when comparing the baseline with the follow-up period.

CONCLUSION

The collaborative's process was associated with fewer infections. SPC suggested that systematic changes occurred. The remaining challenges include sustaining or even further reducing the infection rate.

Skeletal muscle acidosis correlates with the severity of blood volume loss during shock and resuscitation

BACKGROUND

Continuous assessment of tissue perfusion and oxygen utilization may allow for early recognition and correction of hemorrhagic shock. We hypothesized that continuously monitoring skeletal muscle (SM) PO2, PCO2, and pH during shock would provide an easily accessible method for assessing the severity of blood loss and the efficacy of resuscitation.

METHODS

Thirteen anesthetized pigs (25-35 kg) underwent laparotomy and femoral vessel cannulation. Multiparameter fiberoptic sensors were placed in the deltoid (SM) and femoral artery. Ventilation was maintained at a PaCO2 of 40-45 mm Hg. Total blood volume (TBV) was measured using an Evans blue dye technique. Animals were bled for 15 minutes, maintained at a mean arterial pressure (MAP) of 40 mm Hg for 1 hour, resuscitated (shed blood + 2 times shed volume in normal saline) and observed for 1 hour. Four animals served as controls (sham hemorrhage). Blood and tissue samples were taken at each time point.

RESULTS

Blood loss ranged from 28.5-56% of TBV. SM pH and SM PO2 levels fell rapidly with shock. SM PO2 returned to normal with resuscitation; however, SM pH did not return to baseline. SM PCO2 significantly rose with shock, but returned to baseline promptly with resuscitation. There was a significant correlation between SM pH and blood volume loss at end shock (r2 = 0.73, p < 0.001) and recovery (r2 = 0.84, p < 0.001). Animals (n = 2) whose SM pH did not recover to 7.2 were found to have ongoing blood loss from biopsy sites and persistent tissue hypercarbia despite normal MAP.

CONCLUSION

Continuous multiparameter monitoring of SM provides a minimally invasive method for assessing severity of shock and efficacy of resuscitation. Both PCO2 and PO2 levels change rapidly with shock and resuscitation. SM pH is directly proportional to lost blood volume. Persistent SM acidosis (pH < 7.2) and elevated PCO2 levels suggest incomplete resuscitation despite normalized hemodynamics.

By any other name: when will preschoolers produce several labels for a referent?

Two experiments investigated why preschool children sometimes produce multiple words for a referent (i.e. polynomy), but other times seem to allow only one word. In Experiment 1, 40 three- and four-year-olds completed a modification of Deák & Maratsos' (1998) naming task. Although social demands to produce multiple words were reduced, children produced, on average, more than two words per object. Number of words produced was predicted by receptive vocabulary. Lexical insight (i.e. knowing that a word refers to function or appearance) and metalexical beliefs (i.e. that a hypothetical referent has one label, or more than one) were not preconditions of polynomy. Polynomy was independent of bias to map novel words to unfamiliar referents. In Experiment 2, 40 three- and four-year-olds learned new words for nameable objects. Children showed a correction effect, yet produced more than two words per object. Children do not have a generalized one-word-per-object bias, even during word learning. Other explanations (e.g. contextual restriction of lexical access) are discussed.

Is a share buyback right for your company?

Contrary to popular wisdom, buybacks don't create value by raising earnings per share. But they do indeed create value, and in two very different ways. First, a buyback sends signals about the company's prospects to the market--hopefully, that prospects are so good that the best investment managers can make right now is in their own company. But investors won't see it that way if other, negative, signals are coming from the company, and it's rarely a good idea for companies in high-growth industries, where investors expect that money to be spent pursuing new opportunities. Second, when financed as a debt issue, a buyback is essentially an exchange of equity for debt, conferring the traditional benefits of leverage--a tax shield and a discipline for managers. For such a buyback to make sense, a company would need to have taxable profits in need of shielding, of course, and be able to predict its future cash flows fairly accurately. Justin Pettit has found that managers routinely underestimate how many shares they need to buy to send a credible signal to the markets, and he offers a way to calculate that number. He also goes through the iterative steps involved in working out how many shares must be purchased to reach a target level of debt. Then he takes a look at the advantages and disadvantages of the three most common ways that companies make the actual purchases--open-market purchases, fixed-price tender offers, and auction-based tender offers. When a company's performance is lagging, a share buyback can look attractive. Unfortunately, a buyback can backfire--unless executives understand why, when, and how to use this powerful and risky tool.

Bioelectrical impedance analysis in the evaluation of the nutritional status of continuous ambulatory peritoneal dialysis patients

The authors evaluated the nutritional status of 47 continuous ambulatory peritoneal dialysis (CAPD) patients, 26 men (age 58.9 +/- 14.6 years, duration on CAPD 27.3 +/- 18.3 months) and 21 women (age 56.2 +/- 14.9 years, duration on CAPD 34.5 +/- 23.4 months), using subjective global assessment (SGA), an established method for the nutritional assessment of dialysis patients, and bioelectrical impedance analysis (BIA: body cell mass, fat mass, and phase angle). Of the studied patients, 19 were diabetic (age 59.7 +/- 13.8 years, duration on CAPD 29.2 +/- 19.7 months) and 28 were non diabetic (age 53.9 +/- 14.3 years, duration on CAPD 31.5 +/- 21.8 months. According to SGA, 24 patients were scored as well nourished (Group I), 18 as mildly malnourished (Group II), and 5 as moderately malnourished (Group III). No patient scored as severely malnourished (Group IV). Analysis of the main nutritional parameters for the subgroups revealed a proportional decrease in phase angle, with a statistically significant correlation (p < 0.009) between phase angle and SGA. No significant difference was seen in serum albumin levels between patients in Group I and Group II, but the mean level was significantly lower in patients in Group III compared to Group I. The nutritional and biochemical data in diabetic patients and non diabetic patients were not significantly different. BIA phase angle seems to be a simple and reliable method for the routine assessment of nutritional status in CAPD patients.

Effects of amino acid dialysate on appetite in CAPD patients

The use of amino acid (AA) dialysate in CAPD patients may have theoretical disadvantages, since protein ingestion is known to suppress food intake in humans disproportionately to its energy value. Therefore we measured subjective appetite and food intake of CAPD patients in a cross-over study of 16 subjects (age 22-75 years, BMI 19-31, > 3 months on CAPD, non-diabetic and not protein malnourished). They received, in random order, either 4 weeks of dextrose only (their usual treatment), or one AA (1%) exchange replacing the first dextrose exchange each day. Subjective measurements of food intake (3 day food record) and quantitative measurements of lunch time food intake were obtained during a morning dextrose exchange after 28 days of each regimen. Except for a reduction in feelings of fullness during the AA treatment, there were no effects on feelings of hunger/satiety, food appeal, lunch-time food intake, or on 3-day food intake. We conclude that the use of a daily AA (1%) dialysate for 4 weeks does not affect subjective appetite or food intake of CAPD patients. There may even be a beneficial effect as the feeling of fullness decreased with the AA treatment.

Use of lymphoscintigraphy in chyluria

The roentgenographic procedure of choice in delineating lymphatic channels has been lymphangiography. Recently, radionuclide lymphoscintigraphy has been used to outline lymphatics in patients with various lymphatic disorders. We present and compare the results of lymphangiography and lymphoscintigraphy in 2 patients with chyluria. Since the results of lymphoscintigraphy correlated with lymphangiography, the application of this less invasive technique in the diagnosis and management of chyluria may be warranted.

Reconstruction of penile agenesis by a posterior sagittal approach

Penile agenesis is a rare condition requiring gender reassignment and staged perineal reconstruction. This report describes two children reconstructed by taking advantage of the posterior sagittal approach. This approach allows a precise anatomic dissection, construction of a neovagina and accurate positioning of all perineal orifices. We think that this is the preferred approach for this rare condition.

Isolation and experimental chicken-embryo-inoculation studies with budgerigar papovavirus

Attempts to isolate and identify budgerigar papovavirus (BPV) were made during three separate outbreaks of disease diagnosed on pathological grounds. Direct electron microscopy was successful only when large areas of skin were extensively disrupted to release virus and then extracted with fluorocarbon to remove lipids. Direct inoculation of budgerigar tissue suspensions into chicken embryos or chicken cell cultures failed to produce detectable virus. However, when primary cultures of liver and kidney were prepared from affected budgerigars, BPV could be detected by electron microscopy and by the production of a cytopathic effect at the third or fourth passage in cell cultures. The isolated virus was pathogenic for 10-day-old but not 11- or 12-day-old chicken embryos. Inoculated 11- and 12-day-old embryos produced antibodies to BPV that were detectable 2 weeks after hatching by agar-gel-immunodiffusion tests.