Total skin electron beam therapy is a treatment option in patients with mycosis fungoides (MF) affecting a significant amount of the body surface. For patients with involvement of soles and interdigital folds, however, this approach is ineffective, requiring alternatives such as localised radiotherapy (RT). Although electron beams are well suited for superficial lesions, on irregular surfaces it provides inadequate tumour coverage and excess dose variance, requiring photon irradiation with tissue compensation.

We present the case of a patient with extensive cutaneous MF with skin lesions spread over both lower limbs and treated on these affected areas with photon beam RT. Long sheets of paraffin gauze dressings were used to create a 0·5-cm-thick bolus. The patient received a single fraction of 8 Gy. In vivo dosimetry using Gafchromic films was performed.

After 3 months, a complete response was achieved. In this case, paraffin gauze bolus proved to be an inexpensive, convenient, effective and flexible method for irregular superficial cancer irradiations.

Paraffin gauze bolus is a suitable option for irregular contours.

To modify the final dose delivered to superficial tissues and to modulate dose distribution near irradiated surface, different boluses are used. Air gaps often form under the bolus affecting dose distribution. This study aimed to evaluate the effect of an air gap under the bolus radiation on dose delivery.

To evaluate the impact of the air gap, both helical tomotherapy (HT) and direct tomotherapy (DT) were performed in a simulation study.

The maximum dose to bolus in DT plans was bigger than that used in HT plans. The maximum dose delivered to the bolus depended on the air gap size. However, the maximum dose to bolus in all HT plans was within the acceptable value range. Acceptable value was set to up to 107% of the prescription dose. In the simulation performed in this study, the acceptable air gap under bolus was up to 15 mm and below 5 mm in HT and DT plans, respectively.

HT technique is a good choice, but DT technique can be also used if the bolus position can be reproduced accurately. Thus, the reproducibility of the bolus position between planning and treatment is very important.

Bolus material is frequently used on patient’s skin during radiation therapy to reduce or remove build-up effect for high-energy beams. However, the air-gaps formed between the bolus and the skin’s irregular surface reduce the accuracy of treatment planning. To achieve a good treatment outcome using bolus, experimental investigations are required to choose its thickness and to quantify the air-gap effect.

Measurements for a 6 MV photon beam with a fixed source surface distance were carried out using the 31021 Semiflex 3D chamber into the water phantom. Firstly, the depth of maximum dose (R100) and the dose value at surface (Ds) were evaluated as a function of bolus thickness for some square fields. Secondly, to test the effect of the air-gaps ranged from 5 to 30 mm with a step of 5 mm between the bolus and the phantom surface, a water-equivalent RW3 (Goettingen White Water) slab form of 10 mm thickness was considered as a bolus.

We observed that the linear behaviour of R100 in terms of the bolus thickness makes the choice of this parameter more convenient depending on field size. In addition, increasing the air-gaps widens the penumbra and created electrons that have a greater probability to quit the radiation field borders before reaching the surface. The dose spread of the off-field area could have a significant influence on the patient treatment.

Based on dose distribution comparisons between the measurements with and without air-gaps for the field size of 100 mm × 100 mm, it has been demonstrated that a maximum air-gap value lower than 5 mm would be desirable for an efficient use of the bolus technique.

In radiotherapy (RT) bolus material is used to increase skin dose and eliminate the ‘skin-sparing’ effect. Bolus fabrication is limited to the expertise of the practitioner and is time and resource intensive for both patients and staff to construct bolus. In addition, prefabricated bolus does not always conform to irregular surfaces resulting in variations to dose distribution at the skin surface. The purpose of this paper is to ascertain whether it is feasible to improve bolus conformity within radiation therapy by using a 3D printer to fabricate bolus.

A literature review was conducted that utilised Boolean terminology and included keywords; (‘3d’ OR ‘3-dimensional’ OR ‘three dimensional’) ‘bolus’ OR ‘boli’ conform*, (‘Radiation therapy’ OR ‘radiotherapy’) Printing.

Several key papers were identified and critically evaluated based of the title of the feasibility of improving bolus conformity with the used of 3D printing. Several fabrication material devices were explored.

The literature advocates that fused deposition modelling fabrication device clear polylactic acid material to be an adequate product to construct 3D printed bolus and conform to irregular surfaces. 3D bolus would prove advantageous for volumetric arc therapy/intensity modulated radiation therapy techniques as literature has shown the presence of air gaps, small field sizes and large beam obliquity can result in a >10% dose reduction at skin surface.