3D Printed Rigid Bolus Versus Silicone Bolus: A Comparative Study
试验速览
- 阶段
- 不适用
- 状态
- 撤回
- 主要终点
- Air Gap measurement
研究概览
简要总结
This study compares two types of 3D-printed skin bolus (rigid and flexible) used to optimize the treatment of tumors/cancers involving the skin. Each patient will have both types of bolus made, with each will be used on alternating days. The goal is to determine if one type of bolus provides a better fit and thus radiotherapy plan, the ease of use of each type of bolus, and patient reported feedback.
详细描述
Need for Skin Bolus during Radiotherapy for Cancers that Involve the Skin Using standard megavoltage (MV) radiotherapy to treat tumors that involve the skin is technically challenging as without modification, the high-energy radiotherapy machines under-dose the superficial tissue. This is a problem, as this may lead to an inadequate radiation dose being delivered to the skin, thus compromising tumor control. To compensate for this, a flexible polymer material ("bolus") measuring 5-10mm in thickness is placed over the skin during radiotherapy.
There are many types of boluses used internationally from rubber to candle wax slabs. The bolus allows the radiation dose to build up so that a sufficient dose is deposited at the skin. Use of bolus for cancers involving the skin is considered the standard of care when using conventional MV radiotherapy.
Challenges of Using Conventional Bolus Many standard boluses are slightly flexible, but are not able to follow significant changes in the underlying contours. When a bolus is not able to follow an individual's unique 'peaks and valleys' in contour, it can lead to air gaps between the bolus and the skin. An air gap, which is easily seen during imaging, can also vary on a day-to-day basis due to slight changes in positioning of the bolus prior to radiotherapy treatment. The varying air gaps can affect how much radiation dose is getting to the skin, and can potentially lead to under-dosing of the cancer cells in the skin. Even small air gaps (i.e. 5mm in thickness), can cause a 5% error in dose, which exceeds the safe tolerance for treatment.
Areas where this can be a problem are where the patient's anatomy undergoes significant topographical changes in a small area. Examples of this include the ear, nose, top of head. Patients with metastatic cancer can also have large lymph nodes or masses that are growing towards the skin that can be difficult to accommodate with standard bolus materials.
3D-Printed Bolus One method to overcome challenging anatomy for cases that require skin bolus for radiotherapy is the use of 3D-printed bolus. This technology uses data acquired from a CT scan of the affected area. The patients contour can then be used to create an individualized bolus that matches the patient contour for the treatment field. This technology has been demonstrated to improve fit (less air gaps) and decreased radiotherapy treatment time. The bolus used in this study was rigid.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Other
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Pathologically (histologically or cytologically) proven diagnosis of a primary skin cancer or metastatic cancer with involvement of the skin or underlying soft tissues
- •Being treated with radiation therapy that requires the use of bolus to ensure adequate radiotherapy dose to the skin in the affected area
- •Planned for palliative or curative intent radiotherapy using megavoltage (MV) photons
- •Site of involvement has significant contour change, leading to anticipated challenges using conventional bolus material
- •Patient must be competent and able to complete informed consent
- •Women of childbearing potential must be proven to not be pregnant or breast feeding
排除标准
- •Patient being treated with a radiotherapy technique that does not require bolus
- •Patient being treated with a radiotherapy technique other than MV photons (i.e. electrons, brachytherapy, kilovoltage (kV) photons)
- •Patient of childbearing potential who is pregnant, actively trying to become pregnant or breast feeding
- •Allergy to silicone or other components of either the 3D printed rigid or flexible bolus.
- •Size of the bolus required for treatment exceeds 25cm in maximum diameter
结局指标
主要结局
Air Gap measurement
时间窗: 6 weeks
Measurement of the gap between the bolus and the surface of the patient
Planned versus expected radiation duse
时间窗: 6 weeks
Comparison of the planned radiation dose at skin, and that measured during radiation therapy treatment
次要结局
- Patient Reported Outcomes(6 weeks)
- Challenges with Bolus Use(6 weeks)
- Ease of Use(6 weeks)
- Radiation Therapist ease of use(6 weeks)
- Fabrication time(2 weeks)
- Successful fabrication(2 weeks)
研究者
Lara Best, MD, FRCPC, MMEd
Radiation Oncologist
Nova Scotia Cancer Centre