Genital Feminizing Surgery without Vaginoplasty as a Safe, Aesthetic, and Cost-Effective Option for Gender-Affirming Surgery for Transwomen.

Gender affirming surgery (GAS) has important impacts for people with gender incongruence (GI), both physically and socially. As the societal acceptance of gender diversity spreads, the number of individuals with GI who wish to be identified as the gender of their choice is increasing. Indeed, many elderly people who have lived a long time with GI now wish to undergo GAS, but face greater surgical risks due to greater burdens of underlying medical conditions. Generally, vaginoplasty is performed for transwomen; however, this surgery is time-consuming and involves heavy bleeding, and thus, should be avoided in elderly people. A less invasive technique is needed. In this article, we describe a new, less invasive genital feminizing surgical technique for transwomen with reports from two clinical cases. We present this novel technique as a safe, aesthetic, and cost-effective option for gender-affirming surgery for transwomen.

Lower-Limb Lymphatic Drainage Pathways and Lymph Nodes: A CT Lymphangiography Cadaver Study.

Background Most lymphatic imaging examinations of the lower limb require intradermal or subcutaneous injection of tracer material into the foot to demonstrate the lymphatic vessels; however, no standard protocol exists, and single or multiple injections are applied at different sites. Purpose To determine the three-dimensional relationships between each lymphatic group of the lower limb and corresponding regional lymph nodes. Materials and Methods A total of 130 lower limbs (55 from men and 75 from women) from 83 fresh human cadavers were studied. Lymphatic vessels were first visualized by using indocyanine green fluorescent lymphography with 19 injection sites in the foot, classified into four distinct lymphatic groups (anteromedial, anterolateral, posteromedial, and posterolateral); dilute oil-based contrast material was then injected. Next, specimens were scanned with CT and three-dimensional images were analyzed. Results The anteromedial and anterolateral lymphatic groups of the lower-leg lymphatic vessels were independent of each other and connected to different regional lymph nodes in the inguinal region. The posteromedial group and the anteromedial group in the lower leg drained to the same inguinal lymph nodes. Only the posterolateral group of lymphatic vessels in the lower leg drained to the popliteal lymph nodes. Leg lymphatic drainage pathways were independent of genital pathways. Conclusion Standard injection sites at the web spaces between the toes did not help visualize some lymph nodes of the lower leg. Additional injection sites in the medial, lateral, and posterior aspect of the foot would be better for evaluating the whole lymphatic pathways and regional lymph nodes and for improving understanding of leg lymphedema. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Weiss and Liddel in this issue.

Characterization of robust optimization for VMAT plan for liver cancer.

PURPOSE: We investigated the feasibility of robust optimization for volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) for liver cancer in comparison with planning target volume (PTV)-based optimized plans. Treatment plan quality, robustness, complexity, and accuracy of dose delivery were assessed. METHODS: Ten liver cancer patients were selected for this study. PTV-based optimized plans with an 8-mm PTV margin and robust optimized plans with an 8-mm setup uncertainty were generated. Plan perturbed doses were evaluated using a setup error of 8 mm in all directions from the isocenter. The dosimetric comparison parameters were clinical target volume (CTV) doses (D98%, D50%, and D2%), liver doses, and monitor unit (MU). Plan complexity was evaluated using the modulation complexity score for VMAT (MCSv). RESULTS: There was no significant difference between the two optimizations with respect to CTV doses and MUs. Robust optimized plans had a higher liver dose than did PTV-based optimized plans. Plan perturbed dose evaluations showed that doses to the CTV for the robust optimized plans had small variations. Robust optimized plans were less complex than PTV-based optimized plans. Robust optimized plans had statistically significant fewer leaf position errors than did PTV-based optimized plans. CONCLUSIONS: Comparison of treatment plan quality, robustness, and plan complexity of both optimizations showed that robust optimization could be feasibile for VMAT of liver cancer.

[Improvement of Nonuniformity on Flatbed Scanner for Radiochromic Film Dosimetry Using Average Correction Factor with Multi-direction Scan Data].

In order to correct the lateral effect caused by the light source of the flatbed scanner in the Gafchromic film EBT3, the usefulness of the correction method using the average value of the correction coefficient considering the scan directions were evaluated. EBT3 was scanned from four directions to measure the optical density (OD) of the red, blue, and, red/blue components and the correction coefficient were calculated. For the correction coefficients, average values were calculated for the purpose of use, when the scan directions could not be aligned (average lateral effect correction). Correction accuracy was verified with the pass rate of gamma analysis (3 mm/3%, threshold 30%) of the dose distribution using the EBT3 film irradiated with the step pattern. OD of the red, blue, and, red/blue components in the scanning vertical direction tended to be higher in the center than in the peripheral portion. The pass rate of the step pattern was the red component's before correction, from 26.9 to 45.1% (before correction), from 84.1 to 96.7% (after correction), the red/blue component, from 37.6 to 48.4% (before correction) and from 84.4 to 96.7% (after correction). When using the correction coefficient using the average value, the pass rate was 89.8% for the red component and 94.7% for the red/blue component. The lateral effect correction improves the accuracy of the dose distribution verification, and the correction coefficient using the average value is useful when the scanning direction is different from that at the time of obtaining the dose concentration curve.

Developing Microsurgery through Experience in Yangon General Hospital, Myanmar.

Although many surgical centers perform microsurgery routinely in developed countries, performing microsurgery is challenging in resource-poor developing countries, such as Myanmar. With the establishment of educational training programs and the assistance of volunteer plastic surgical teams, local plastic surgeons can learn the techniques of microsurgery and apply them clinically. The purpose of this study was to establish baseline data and define the challenges of performing microsurgery in Yangon General Hospital, Myanmar. Sixty-four patients underwent reconstruction with free flaps from January 2015 to January 2018. All clinical records of these cases were assessed. The number of free flap reconstructions performed increased from 11 in the first year to 24 in the third year. The anterolateral thigh flap was the most commonly used (42%). The most common sites of reconstruction were mandible and intraoral defects. Total flap survival occurred in 58 of 64 patients (89%). The total salvageable flap rate for revision surgery was 66.6%; the successful revision rate was highest in 2017, with fewer complications. The flap salvage rates increased and the operative duration decreased as clinical experience improved. Establishing a microsurgical center requires a strong multidisciplinary team, clinical experience, continuous learning, sensible clinical application, and effective interdepartmental and intradepartmental cooperation.

Tolerance levels of mass density for CT number calibration in photon radiation therapy.

Computed tomography (CT) data are required to calculate the dose distribution in a patient's body. Generally, there are two CT number calibration methods for commercial radiotherapy treatment planning system (RTPS), namely CT number-relative electron density calibration (CT-RED calibration) and CT number-mass density calibration (CT-MD calibration). In a previous study, the tolerance levels of CT-RED calibration were established for each tissue type. The tolerance levels were established when the relative dose error to local dose reached 2%. However, the tolerance levels of CT-MD calibration are not established yet. We established the tolerance levels of CT-MD calibration based on the tolerance levels of CT-RED calibration. In order to convert mass density (MD) to relative electron density (RED), the conversion factors were determined with adult reference computational phantom data available in the International Commission on Radiological Protection publication 110 (ICRP-110). In order to validate the practicability of the conversion factor, the relative dose error and the dose linearity were validated with multiple RTPSes and dose calculation algorithms for two groups, namely, CT-RED calibration and CT-MD calibration. The tolerance levels of CT-MD calibration were determined from the tolerance levels of CT-RED calibration with conversion factors. The converted RED from MD was compared with actual RED calculated from ICRP-110. The conversion error was within ±0.01 for most standard organs. It was assumed that the conversion error was sufficiently small. The relative dose error difference for two groups was less than 0.3% for each tissue type. Therefore, the tolerance levels for CT-MD calibration were determined from the tolerance levels of CT-RED calibration with the conversion factors. The MD tolerance levels for lung, adipose/muscle, and cartilage/spongy-bone corresponded to ±0.044, ±0.022, and ±0.045 g/cm3 , respectively. The tolerance levels were useful in terms of approving the CT-MD calibration table for clinical use.

Nerve Switch for Reducing Synkinesis After Gracilis Muscle Transfer Innervated Via the Masseter Nerve.

BACKGROUND: In surgical treatment for longstanding facial paralysis, muscle transplantation is considered a useful and important method. To obtain a spontaneous smile, the use of the facial nerve of the healthy side as a motor source is better, but use of the masseter nerve allows prompt reinnervation and powerful movement. However, in some patients in whom the masseter nerve is used, separating masticatory movement and commissure contraction is difficult. Solutions for such patients have not been determined. CASE HISTORY AND DISCUSSION: A 46-year-old female patient presented with longstanding complete facial paralysis after resection of a right acoustic neurinoma. As initial surgery, free gracilis transfer was performed on the cheek, but the patient experienced commissure movement during meals postsurgery. Secondary corrective surgery was performed to detach the motor nerve of the gracilis from the masseter nerve and suture it to the facial nerve of the healthy side via cross-face nerve graft. The symptom improved but partially recurred. Improvement in synkinetic movement can be obtained by performing cross-face nerve grafting and subsequent nerve switch.

Exercise-Loaded Indocyanine Green Fluorescence Lymphangiography for Diagnosing Lymphedema.

BACKGROUND: Indocyanine green (ICG) fluorescence lymphography (ICGLG) that can visualize the lymphatic vessel and its flow noninvasively and dynamically was developed in 2007. It is frequently used to observe the function and pathway of the lymphatic vessels. ICGLG is simple and easy to perform, and it is useful for understanding the condition of the lymphatic system in real time. However, its protocol is not standardized. In addition, the lymphatic flow is enhanced by an exercise load such as walking. Till now, there is no report of exercise-loaded ICGLG. Therefore, we aimed to shorten the examination time and establish a standard ICGLG protocol. METHODS: We examined 63 patients (126 lower limbs) who visited our clinic for lower extremity edema. We observed detailed images of exercise-loaded ICGLG and examined the changes in findings over time in affected legs classified according to the International Society of Lymphedema. After ICG was injected, the participants exercised for 30 minutes. We observed the farthest proximal point where any ICG could be observed and the appearance of dermal backflow (DB), which is a specific finding of lymphedema, every 5 minutes. RESULTS: The proximal migration speed of ICG tended to slow as the disease stage worsened. For all disease stages, after 20 minutes of exercise, the DB appearance rate did not change further. The rates were 0% for legs with stage 0 lymphedema, 50% for legs with stage 1 lymphedema, and 100% for legs with stages 2a and 2b lymphedema. CONCLUSION: The appropriate exercise duration after ICG injection is 20 minutes. ICGLG is useful for screening for lymphedema.

Effect of image quality on correlation modeling error using a fiducial marker in a gimbaled linear accelerator.

The purpose of this study was to investigate the effect of image quality under various imaging parameters (60, 70, 80, 90, 100, 110, and 120 kV at 200 mA and 10 ms/63, 80, 100, 160, 200, 250, and 320 mA at 120 kV and 10 ms) and the diameter of the fiducial marker (0.25, 0.50, 0.75, and 1.10 mm) on the correlation modeling error for dynamic tumor tracking (DTT) in the Vero4DRT system. Each fiducial marker was inserted into the center of the 30 × 30 × 10 cm3 water-equivalent phantom. A programmable respiratory motion table was used to simulate breathing-induced organ motion, with an amplitude of ±20 mm and a breathing cycle of 4 s. The correlation modeling error was calculated from the absolute difference between the detected and predicted target positions in the cranio-caudal direction. The image contrast of the fiducial marker was enhanced with increasing kV and mA. Increasing the diameter of the fiducial marker also enhanced the image contrast. Correlation-modeling error does not depend on the image quality and fiducial marker diameter. A lower kV setting did not generate a 4D model due to poor image contrast. All fiducial marker diameters were identified as good candidates for DTT in the Vero4DRT system.

Image quality and absorbed dose comparison of single- and dual-source cone-beam computed tomography.

PURPOSE: Dual-source cone-beam computed tomography (DCBCT) is currently available in the Vero4DRT image-guided radiotherapy system. We evaluated the image quality and absorbed dose for DCBCT and compared the values with those for single-source CBCT (SCBCT). METHODS: Image uniformity, Hounsfield unit (HU) linearity, image contrast, and spatial resolution were evaluated using a Catphan phantom. The rotation angle for acquiring SCBCT and DCBCT images is 215° and 115°, respectively. The image uniformity was calculated using measurements obtained at the center and four peripheral positions. The HUs of seven materials inserted into the phantom were measured to evaluate HU linearity and image contrast. The Catphan phantom was scanned with a conventional CT scanner to measure the reference HU for each material. The spatial resolution was calculated using high-resolution pattern modules. Image quality was analyzed using ImageJ software ver. 1.49. The absorbed dose was measured using a 0.6-cm3 ionization chamber with a 16-cm-diameter cylindrical phantom, at the center and four peripheral positions of the phantom, and calculated using weighted cone-beam CT dose index (CBCTDIw ). RESULTS: Compared with that of SCBCT, the image uniformity of DCBCT was slightly reduced. A strong linear correlation existed between the measured HU for DCBCT and the reference HU, although the linear regression slope was different from that of the reference HU. DCBCT had poorer image contrast than did SCBCT, particularly with a high-contrast material. There was no significant difference between the spatial resolutions of SCBCT and DCBCT. The absorbed dose for DCBCT was higher than that for SCBCT, because in DCBCT, the two x-ray projections overlap between 45° and 70°. CONCLUSIONS: We found that the image quality was poorer and the absorbed dose was higher for DCBCT than for SCBCT in the Vero4DRT.

Tolerance levels of CT number to electron density table for photon beam in radiotherapy treatment planning system.

The accuracy of computed tomography number to electron density (CT-ED) calibration is a key component for dose calculations in an inhomogeneous medium. In a previous work, it was shown that the tolerance levels of CT-ED calibration became stricter with an increase in tissue thickness and decrease in the effective energy of a photon beam. For the last decade, a low effective energy photon beam (e.g., flattening-filter-free (FFF)) has been used in clinical sites. However, its tolerance level has not been established yet. We established a relative electron density (ED) tolerance level for each tissue type with an FFF beam. The tolerance levels were calculated using the tissue maximum ratio (TMR) and each corresponding maximum tissue thickness. To determine the relative ED tolerance level, TMR data from a Varian accelerator and the adult reference computational phantom data in the International Commission on Radiological Protection publication 110 (ICRP-110 phantom) were used in this study. The 52 tissue components of the ICRP-110 phantom were classified by mass density as five tissues groups including lung, adipose/muscle, cartilage/spongy-bone, cortical bone, and tooth tissue. In addition, the relative ED tolerance level of each tissue group was calculated when the relative dose error to local dose reached 2%. The relative ED tolerances of a 6 MVFFF beam for lung, adipose/muscle, and cartilage/spongy-bone were ±0.044, ±0.022, and ±0.044, respectively. The thicknesses of the cortical bone and tooth groups were too small to define the tolerance levels. Because the tolerance levels of CT-ED calibration are stricter with a decrease in the effective energy of the photon beam, the tolerance levels are determined by the lowest effective energy in useable beams for radiotherapy treatment planning systems.

4D modeling in a gimbaled linear accelerator by using gold anchor markers.

PURPOSE: The purpose of this study was to verify whether the dynamic tumor tracking (DTT) feature of a Vero4DRT system performs with 10-mm-long and 0.28 mm diameter gold anchor markers. METHODS: Gold anchor markers with a length of 10 mm and a diameter of 0.28 mm were used. Gold anchor markers were injected with short and long types into bolus material. These markers were sandwiched by a Tough Water (TW) phantom in the bolus material. For the investigation of 4-dimensional (4D) modeling feasibility under various phantom thicknesses, the TW phantom was added at 2 cm intervals (in upper and lower each by 1 cm). A programmable respiratory motion table was used to simulate breathing-induced organ motion, with an amplitude of 30 mm and a breathing cycle of 3 s. X-ray imaging parameters of 80 kV and 125 kV (320 mA and 5 ms) were used. The least detection error of the fiducial marker was defined as the 4D-modeling limitation. RESULTS: The 4D modeling process was attempted using short and long marker types and its limitation with the short and long types was with phantom thicknesses of 6 and 10 cm at 80 kV and 125 kV, respectively. However, the loss in detectability of the gold anchor because of 4D-modeling errors was found to be approximately 6% (2/31) with a phantom thickness of 2 cm under 125 kV. 4D-modeling could be performed except under the described conditions. CONCLUSIONS: This work showed that a 10-mm-long gold anchor marker in short and long types can be used with DTT for short water equivalent path length site, such as lung cancer patients, in the Vero4DRT system.

[Influence of Changing Respirator Pattern on Dynamic Tumor Tracking Accuracy with Gimbaled Linac System Using a Digital Camera].

It is important for high-precision radiation therapy that tracking accuracy in dynamic tumor tracking (DTT) using the gimbal X-ray head. We evaluated the tracking accuracy under various respiratory patterns differ from a correlation model [four-dimensional model (4D-model)] in real-time using a digital camera. A sheet of paper with luminous line was placed on the programmable respiratory motion table (CIRS Inc.) and operated with the laser projector. The luminous line was defined as a target and the laser was defined as a gimbal. Motion table was operated at a period of 4 s and amplitude of ±10 mm to create 4D-modeling. This movement was defined as the basic operation. To investigate the tracking accuracy, target and gimbal positions were recorded using a digital camera under amplitudes (±5-20 mm) and periods (2-8 s) and analyzed by ImageJ software (NIH). The maximum tracking errors under various period and amplitude were 1.7-0.9 mm and 0.4-1.9 mm, respectively. From the creation of 4D-modeling, it was confirmed that when the period has shortened and the amplitude has increased, tracking accuracy was reduced.

In vitro fertilization and pregnancy management in a woman with acquired idiopathic chylous ascites.

Acquired idiopathic chylous ascites is extremely rare in women of reproductive age. This is the first report describing successful infertility and pregnancy management in a patient with idiopathic chylous ascites. A 23-year-old woman presented with abdominal distention and was diagnosed with idiopathic fluid collection. A lymphogram revealed lymphatic leakage from the right renal hilum. Lymphatic-venous anastomosis of the thoracic duct was performed thrice, but the chylous ascites persisted. In vitro fertilization was performed because natural conception was not possible. Just prior to oocyte retrieval, transvaginal drainage of ascites was performed. In total, nine blastocysts were obtained and cryopreserved. Single frozen embryo transfer was performed, including hormone replacement therapy. The patient became pregnant and the ascites spontaneously decreased as the pregnancy progressed, finally disappearing around gestational week 20. A healthy baby was delivered transvaginally. Ascites began to reaccumulate on post-partum day 1 and returned to the pre-pregnancy level within a month.

Three-Dimensional Imaging of Lymphatic System in Lymphedema Legs Using Interstitial Computed Tomography-lymphography.

As a new trial, we used interstitial computed tomography-lymphography (CT-LG) in 10 patients with lower extremity lymphedema (n=20 limbs) at stage 0, 1, 2, or 3 under the International Society of Lymphology (ISL) classification. In all cases, CT-LG, lymphoscintigraphy, and indocyanine green fluorescence-lymphography (ICG-LG) were performed. In the examination of the ascending level of depicted lymphatic vessels, we measured the diameters of lymphatic vessels detected with CT-LG and conducted an image analysis of dermal backflow of lymph (DB). CT-LG had better resolution than lymphoscintigraphy and enabled the clear visualization of lymphatic vessels with a minimum lumen size of 0.7 mm. CT-LG also showed the three-dimensional architecture of the DB, which originated from deep lymphatic collectors via branched small lymphatic vessels. Our findings are quite valuable not only for detailed examinations of lymphedematous sites and for the lymphedema surgery, but also for investigations of the pathogenesis of lymphedema which has not yet been established. We observed that lymphoscintigraphy could show the lymphatic vessels up to the thigh level in all cases, whereas CT-LG enabled the vessels' visualization up to the leg level at maximum. In conclusion, CT-LG provided adequate and detailed three-dimensional imaging of the lymphatic system in lymphedema patients.

Quality assurance of a gimbaled head swing verification using feature point tracking.

To perform dynamic tumor tracking (DTT) for clinical applications safely and accurately, gimbaled head swing verification is important. We propose a quantitative gimbaled head swing verification method for daily quality assurance (QA), which uses feature point tracking and a web camera. The web camera was placed on a couch at the same position for every gimbaled head swing verification, and could move based on a determined input function (sinusoidal patterns; amplitude: ± 20 mm; cycle: 3 s) in the pan and tilt directions at isocenter plane. Two continuous images were then analyzed for each feature point using the pyramidal Lucas-Kanade (LK) method, which is an optical flow estimation algorithm. We used a tapped hole as a feature point of the gimbaled head. The period and amplitude were analyzed to acquire a quantitative gimbaled head swing value for daily QA. The mean ± SD of the period were 3.00 ± 0.03 (range: 3.00-3.07) s and 3.00 ± 0.02 (range: 3.00-3.07) s in the pan and tilt directions, respectively. The mean ± SD of the relative displacement were 19.7 ± 0.08 (range: 19.6-19.8) mm and 18.9 ± 0.2 (range: 18.4-19.5) mm in the pan and tilt directions, respectively. The gimbaled head swing was reliable for DTT. We propose a quantitative gimbaled head swing verification method for daily QA using the feature point tracking method and a web camera. Our method can quantitatively assess the gimbaled head swing for daily QA from baseline values, measured at the time of acceptance and commissioning.

A Detailed Examination of the Characteristics and Treatment in a Series of 33 Idiopathic Lymphedema Patients.

Background To date, only a few reports have been published on idiopathic lymphedema, and most of these are case reports. In this time, we performed a retrospective review of idiopathic lymphedema patients. Methods Forty patients presented with idiopathic lymphedema that was unrelated to surgery, injury, and medical conditions such as circulatory disease, kidney disease, and thrombotic venous disease. For these patients, we performed a retrospective review for edema-onset age, sex, location and stage of the edema, presence of cellulitis, episode related to edema onset, therapeutic intervention, and follow-up duration in the 33 patients whom we followed up. Results Among the 33 patients with idiopathic lymphedema, there were 11 patients with either congenital or childhood-onset lymphedema, 14 with adult-onset lymphedema, and the remaining 8 patients had an onset age of >60 years. Twenty of the 33 patients had undergone surgical treatment. Of the 19 patients who underwent lymphaticovenular anastomosis (LVA), 2 had good, 4 had fair, and 13 had poor treatment outcomes. Twelve patients successfully received only conservative treatment and follow-up for more than 3 months, without operation. The treatment outcome in these 12 patients was as follows: excellent in 4 patients, good in 6, and fair in 2 patients. Conclusion In this study, the usefulness of LVA for most patients with idiopathic lymphedema was not confirmed. Although this review did not include a conducted case, the indication for new surgical treatments such as vascularized lymph node transfer should be considered in the future.

Effect of tumor amplitude and frequency on 4D modeling of Vero4DRT system.

BACKGROUND: An important issue in indirect dynamic tumor tracking with the Vero4DRT system is the accuracy of the model predictions of the internal target position based on surrogate infrared (IR) marker measurement. We investigated the predictive uncertainty of 4D modeling using an external IR marker, focusing on the effect of the target and surrogate amplitudes and periods. METHODS: A programmable respiratory motion table was used to simulate breathing induced organ motion. Sinusoidal motion sequences were produced by a dynamic phantom with different amplitudes and periods. To investigate the 4D modeling error, the following amplitudes (peak-to-peak: 10-40 mm) and periods (2-8 s) were considered. The 95th percentile 4D modeling error (4D-E95%) between the detected and predicted target position (µ + 2SD) was calculated to investigate the 4D modeling error. RESULTS: 4D-E95% was linearly related to the target motion amplitude with a coefficient of determination R2 = 0.99 and ranged from 0.21 to 0.88 mm. The 4D modeling error ranged from 1.49 to 0.14 mm and gradually decreased with increasing target motion period. CONCLUSIONS: We analyzed the predictive error in 4D modeling and the error due to the amplitude and period of target. 4D modeling error substantially increased with increasing amplitude and decreasing period of the target motion.

Evaluation of cone-beam computed tomography image quality assurance for Vero4DRT system.

We report the characteristics of quality assurance (QA) image for Vero4DRT system with a kilo-voltage (kV) cone-beam computed tomography (CBCT) capability to perform image-guided radiation therapy (IGRT). To acquire a set of CBCT, the kV source is rotated either 215° clockwise (CW) (tube 1 from 5° to 220° and tube 2 from 275° to 130°) or counterclockwise (CCW) (tube 1 from 85° to 230° and tube 2 from 355° to 140°). Image geometry, image uniformity, high/low contrast resolutions, and contrast linearity were measured with a Catphan 504 CT phantom (The Phantom Laboratory, NY). The comparison between measured and expected distances shows an excellent agreement. The CBCT for Vero4DRT system cannot perform a full 360° rotation, which leads to a loss in uniformity for image acquisition. Separations were observed for high-contrast resolution, with eight line pairs per centimeter corresponding to a gap size of 0.063 cm. For low-contrast resolution, the seventh largest hole was visible. This hole has a 4-mm diameter with 1.0% contrast level. We should check the contrast linearity compared with known value, even though it is out of range from the manufacturer manual.

Relationship of the number and size of superficial groin lymph nodes with the stage of secondary lymphatic edema.

PURPOSE: This study evaluated the relationships of the size and number of superficial groin lymph nodes with the lower limb lymphedema stage and thus examined the role of superficial lymphatic lymph nodes in secondary lymphedema development. METHODS: We determined the number and size of superficial groin lymph nodes using horizontal plane computed tomography (CT) and the lymphedema stage in the lower limbs of 25 patients with gynecologic cancer. RESULTS: The patients had an average of 2.92 (range, 1-7) superficial groin lymph nodes; the mean size of the 146 evaluated lymph nodes was 7.55 mm (range, 5-15 mm). In 19 of 25 patients (76%), the side with major edema contained fewer superficial groin lymph nodes. In total, 22 patients (88%) had fewer superficial groin lymph nodes or a smaller total lymph node size on the edematous dominant side. CONCLUSIONS: In this evaluation of the link between superficial groin lymph node laterality and secondary lymphedema staging, we found that patients with large lymph node numbers and sizes tended to present with a relatively earlier stage of lymphedema. Our results therefore suggest that the size and number of superficial groin lymph nodes affect the lymphedema stage. J. Surg. Oncol. 2016;114:940-946. © 2016 Wiley Periodicals, Inc.