Does the standardized helmet technique lead to adequate coverage of the cribriform plate? An analysis of current practice with respect to the ICRU 50 report

Therapy of leptomeningeal metastasis in solid tumors

“…Usually, whole brain radiotherapy (WBRT) is applied in case of cerebral involvement and a focal radiotherapy for spinal lesions. The WBRT technique should ideally be 3D-based CT planning in order to fully include the retroorbital part of the eye socket and the cribriform plate [40][41][42][43][44]. Focal cerebral irradiation of individual regions is not established, but may be discussed in individual cases depending on the location.…”

Shielding in whole brain irradiation in the multileaf collimator era: Dosimetric evaluation of coverage using SFOP guidelines against in-house guidelines

“…Parallel opposed, two lateral portals are utilized, with added customized shielding to protect the surrounding critical structures. [4] The area around the cribriform plate is considered to be gravity-related sanctuary site. [5] However, due to its proximity to the ocular structures, it often gets shielded in cranial radiation.…”

“…The standard German helmet technique has been criticized as it leads to inadequate coverage of the cribriform plate. [2][3][4] In 1999, SFOP (French Society of Pediatric Oncology) gave guidelines for design of cranial shielding in medulloblastoma, [6] which have been subsequently adapted for use in other indications where whole brain radiation is required. A similar but modified guideline for design of cranial shield is used at our center.…”

Differences in Parotid Dosimetry and Expected Normal Tissue Complication Probabilities in Whole Brain Radiation Plans Covering C1 Versus C2

“…Even in the computed tomography (CT) era, radiation treatment fields continue to be designed based on anatomic landmarks identifiable on lateral radiographs of the skull, with a 5 to 10 mm margin placed on the cribriform plate and floor of the middle cranial fossa and 1 to 2 cm of “flash” beyond the anterior, superior, and posterior cranium to ensure dose homogeneity [12]. Variations in the WBRT technique can lead to substantial differences in the mean parotid dose [13].…”

“…Most commonly, the inferior border for the field is placed at either the inferior endplate of the C1 or C2 vertebra. The decision of which vertebral level to cover is typically a matter of physician preference, although coverage through C2 has most commonly been recommended when treating small-cell lung cancer and leukemia via the German Helmet technique [12,14]. The purpose of this study is to compare the dose delivered to the parotid glands in plans covering C1 versus C2.…”