ANEURYSMAL bone cyst may be defined as a cystic lesion of bone containing clefts or spaces filled with blood which is in continuity with the general circulation. It often increases in size very rapidly and may expand the bone to an extreme degree. This expansion is frequently confined to one aspect of the bone.The clinical and radiological appearances of the lesion closely resemble those of osteoclastoma, and the solid parts of it may appear similar histologically, so that it is sometimes classified as a "variant" of the giant cell tumours. Aneurysmal bone cyst, however, frequently commences in childhood when osteoclastoma is very rare.
Only complete excision of the nidus of an osteoid osteoma can guarantee cure. Localization of the nidus by using a gamma camera in theatre (Rinsky et al, 1980) is cumbersome and inaccurate in delineating how much bone should be excised. The use of a sterilizable, portable scaler-ratemeter (Colton & Hardy, 1983) provides good results, but the equipment is expensive to buy and maintain. The use of a scintillation well counter outside theatre to measure counts from bone punch biopsy specimens in and around the suspect area has also been reported (O'Brien et al, 1984). However, up to 24 specimens were required and operative time must have been substantially prolonged.
When a patient presented to our hospital with a probable osteoid osteoma we devised a variation on the above techniques which is reasonably speedy and only requires the type of gamma camera found in most nuclear medicine departments.
Purpose:
To demonstrate that Volumetric Modulated Arc Therapy (VMAT) can be an alternative technique to Brachytherapy Accelerated Partial Breast Irradiation (APBI) for treating large breasted women. The non‐coplanar VMAT technique uses a commercially available couch and a small number of angles. This technique with the patient in the prone position can reduce high skin and critical structure doses in large breasted women, which are usually associated with Brachytherapy APBI.
Methods:
Philips Pinnacle treatment planning system with Smart Arc was used to plan a left sided laterally located excision cavity on a standard prone breast patient setup. Three thirty‐degree arcs entered from the lateral side at respective couch angles of 345, 0, and 15 degrees. A fourth thirty degree arc beam entered from the medial side at a couch angle of 0 degrees. The arcs were selected to avoid critical structures as much as possible. A test run was then performed to verify that the beams did not collide with the patient nor support structures. NSABP B‐39/RTOG 0413 protocol guidelines were used for dose prescription, normal tissue, and target definition.
Results:
Dose Volume Histogram analysis indicated that all parameters were equal or better than RTOG recommendations. Of particular note regarding the plan quality:1.(a) For a prescribed dose of 3850cGy the PTV‐EVAL target volume receiving 100 percent of the dose(V100) was 93; protocol recommendation is V90 > 90 percent. (b) Maximum dose was 110 percent versus the allowed 120 percent .2. Uninvolved percentage of normal breast V100 and V50 were 17 and 47 versus allowed 35 and 60 percent respectively.3. For the skin, V100 was 5.7cc and the max dose to 0.1 cc was 4190cGy.
Conclusion:
Prone Breast non‐coplanar VMAT APBI can achieve better skin cosmesis and lower critical structure doses than Brachytherapy APBI.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.