Pre-irradiation tattooing

Accuracy and Efficiency of Patient Setup Using Surface Imaging versus Skin Tattoos for Accelerated Partial Breast Irradiation

Purpose

Skin tattoos represent the standard approach for surface alignment and setup of breast cancer radiation therapy, yet permanent skin markings contribute to adverse cosmesis and patient dissatisfaction. With the advent of contemporary surface-imaging technology, we evaluated setup accuracy and timing between "tattoo-less" and traditional tattoo-based setup techniques.

Methods and Materials

Patients receiving accelerated partial breast irradiation (APBI) underwent traditional tattoo-based setup (TTB), alternating daily with a tattoo-less setup via surface imaging using AlignRT (ART). Following initial setup, position was verified via daily kV imaging, with matching on surgical clips representing ground truth. Translational shifts (TS) and rotational shifts (RS) were ascertained, as were setup time and total in-room time. Statistical analyses used the Wilcoxon signed rank test and Pitman-Morgan variance test.

Results

A total of 43 patients receiving APBI and 356 treatment fractions were analyzed (174 TTB fractions and 182 using ART). For tattoo-less setup via ART, the median absolute TS were 0.31 cm in the vertical (range, 0.08-0.82), 0.23 cm in the lateral (0.05-0.86), and 0.26 cm in the longitudinal (0.02-0.72) axes. For TTB setup, the corresponding median TS were 0.34 cm (0.05-1.98), 0.31 cm (0.09-1.84), and 0.34 cm (0.08-1.25), respectively. The median magnitude shifts were 0.59 (0.30-1.31) for ART and 0.80 (0.27-2.13) for TTB. ART was not statistically distinguishable from TTB in terms of TS, except in the longitudinal direction (P = .154, .059, and .021, respectively), and was superior to TTB for magnitude shift (P < .001). The variance of each TS variable was significantly narrower for ART compared with TTB (P ≤ .001 vertical, P = .001 lateral, P = .005 longitudinal). The median absolute RS for ART was 0.64° rotation (range, 0.00-1.90), 0.65° roll (0.05-2.90), and 0.30° pitch (0.00-1.50). The corresponding median RS for TTB were 0.80° (0.00-2.50), 0.64° (0.00-3.00), and 0.46° (0.00-2.90), respectively. ART setup was not statistically different from TTB in terms of RS (P = .868, .236, and .079, respectively). ART showed lower variance than TTB in terms of pitch (P = .009). The median total in-room time was shorter for ART than TTB (15.42 vs 17.25 minutes; P = .008), as was the median setup time (11.12 vs 13.00 minutes; P = .001). Moreover, ART had a narrower distribution of setup time with fewer lengthy outliers versus TTB.

Conclusions

These findings suggest that a tattoo-less setup approach with AlignRT may be sufficiently accurate and expeditious to supplant surface tattoos for patients receiving APBI. Further analyses with larger cohorts will determine whether tattoo-based approaches can be replaced by noninvasive surface imaging.

Imaging luminescent tattoo inks for direct visualization of linac and cobalt irradiation

PURPOSE

Tattoo fiducials are commonly used in radiotherapy patient alignment, and recent studies have examined the use of UV-excited luminescent tattoo ink as a cosmetic substitute to make these visible under UV illumination. The goal of this study was to show how luminescent tattoo inks could be excited with MV radiation and imaged during beam delivery for direct visualization of field position.

METHODS

A survey of nine UV-sensitive tattoo inks with various emission spectra were investigated using both UV and MV excitation. Images of liquid solutions were collected under MV excitation using an intensified-CMOS imager. Solid skin-simulating phantoms were imaged with both surface-painted ink and in situ tattooing during dose delivery by both a clinical linear accelerator and cobalt-60 source.

RESULTS

The UV inks have peak fluorescence emission ranging from approximately 440 to 600 nm with lifetimes near 11-16 μs. The luminescence intensity is approximately 6x higher during the x-ray pulse than after the pulse, however, the signal-to-noise is only approximately twice as large. Spatial resolution for imaging was achieved at 1.6 mm accuracy in a skin test phantom. Optical filtering allows for continuous imaging using a cobalt source and provides a mechanism to discriminate ink colors using a monochromatic image sensor.

CONCLUSIONS

This study demonstrates how low-cost inks can be used as fiducial markers and imaged both using time-gated and continuous modes during MV dose delivery. Phantom studies demonstrate the potential application of real-time field verification. Further studies are required to understand if this technique could be used as a tool for radiation dosimetry.

Medical applications of tattooing

Tattooing is an ancient procedure, practiced by humans from all parts of the world for a variety of reasons. However, relatively little is known by the medical audience of the numerous medical conditions where tattooing is employed as a therapeutic modality or a diagnostic method. Tattooing for cosmetic and medicinal purposes, referred to as either micropigmentation, dermatography, or medical tattooing, may ensure permanent camouflage in a wide range of dermatological diseases. It can be a valuable finishing step in several surgical procedures in the fields of craniofacial surgery, plastic and reconstructive operations, cosmetic surgery procedures, and breast reconstruction. Other fields of application of medical tattooing include radiation therapy, endoscopic surgery, and ophthalmology.

Mucosal tattooing in oral cavity carcinoma

Tattooing provides accurate localization for tumor surgery following radiation therapy. This paper describes studies done on tattooing technique and instruments available currently. Procedures tested included hypodermic needles and three types of surgical instruments. Chemical tested included india ink, iron oxide, and colored pigments. India ink and iron oxide used with the Spaulding-Rogers Outliner gave satisfactory tattoos.

Tattooing for preservation of oral and oropharyngeal cancer resection margins

En bloc composite cancer surgery for head and neck tumors is now available with reconstruction. Preoperative adjuvant therapy threatens the concept of wide resection because of alteration of tumor margins. Pre-irradiation tattooing at resection margins will preserve this fundamental surgical doctrine.