A Helical tomotherapy as a robust low-dose treatment alternative for total skin irradiation

Investigation of total skin helical tomotherapy using a 3D-printed total skin bolus

OBJECTIVE

To investigate the effectiveness of using a 3D-printed total skin bolus in total skin helical tomotherapy for the treatment of mycosis fungoides.

MATERIALS AND METHODS

A 65-year-old female patient with a 3-year history of mycosis fungoides underwent treatment using an in-house desktop fused deposition modelling printer to create a total skin bolus made of a 5-mm-thick flexible material, which increased the skin dose through dose building. The patient's scan was segmented into upper and lower sections, with the division line placed 10 cm above the patella. The prescription was to deliver 24 Gy over 24 fractions, given 5 times per week. The plan parameters consisted of a field width of 5 cm, pitch of 0.287 and modulation factor of 3. The complete block was placed 4 cm away from the planned target region to reduce the area of the internal organs at risk, especially the bone marrow. Dose delivery accuracy was verified using point dose verification with a "Cheese" phantom (Gammex RMI, Middleton, WI), 3D plane dose verification with ArcCHECK (Model 1220, Sun Nuclear, Melbourne, FL), and multipoint film dose verification. Megavoltage computed tomography guidance was also utilized to ensure the accuracy of the setup and treatment.

RESULTS

A 5-mm-thick 3D-printed suit was used as a bolus to achieve a target volume coverage of 95% of the prescribed dose. The conformity index and homogeneity index of the lower segment were slightly better than those of the upper segment. As the distance from the skin increased, the dose to the bone marrow gradually decreased, and the dose to other organs at risk remained within clinical requirements. The point dose verification deviation was less than 1%, the 3D plane dose verification was greater than 90%, and the multipoint film dose verification was less than 3%, all of which confirmed the accuracy of the delivered dose. The total treatment time was approximately 1.5 h, which included 0.5 h of wearing the 3D-printed suit and 1 h with the beam on. Patients only experienced mild fatigue, nausea or vomiting, low-grade fever, and grade III bone marrow suppression.

CONCLUSION

The use of a 3D-printed suit for total skin helical tomotherapy can result in a uniform dose distribution, short treatment time, simple implementation process, good clinical outcomes, and low toxicity. This study presents an alternative treatment approach that can potentially yield improved clinical outcomes for mycosis fungoides.

Total Skin Treatment with Helical Arc Radiotherapy

For widespread cutaneous lymphoma, such as mycosis fungoides or leukemia cutis, in patients with acute myeloid leukemia (AML) and for chronic myeloproliferative diseases, total skin irradiation is an efficient treatment modality for disease control. Total skin irradiation aims to homogeneously irradiate the skin of the entire body. However, the natural geometric shape and skin folding of the human body pose challenges to treatment. This article introduces treatment techniques and the evolution of total skin irradiation. Articles on total skin irradiation by helical tomotherapy and the advantages of total skin irradiation by helical tomotherapy are reviewed. Differences among each treatment technique and treatment advantages are compared. Adverse treatment effects and clinical care during irradiation and possible dose regimens are mentioned for future prospects of total skin irradiation.

Application of deblur technology for improving the clarity of digital subtractive angiography

BACKGROUND

Digital subtraction angiography (DSA) is most commonly used in vessel disease examinations and treatments. We aimed to develop a novel deep learning-based method to deblur the large focal spot DSA images, so as to obtain a clearer and sharper cerebrovascular DSA image.

METHODS

The proposed network cascaded several residual dense blocks (RDBs), which contain dense connected layers and local residual learning. Several loss functions for image restoration were investigated. Our training set consisted of 52 paired images of angiography with more than 350,000 cropped patches. The testing set included 10 body phantoms and 80 clinical images of different types of diseases for subjective evaluation. All test images were acquired using a large focal spot, and phantom images were simultaneously acquired using a micro focal spot as ground-truth. Peak-to-noise ratio (PSNR) and structural similarity (SSIM) were determined for quantitative analysis. The deblurring results were compared with the original data, and the image quality was subjectively evaluated and graded by two clinicians.

RESULTS

For quantitative analysis of phantom images, the average PSNR/SSIM based on the deep-learning approach (35.34/0.9566) was better than that of large focal spot images (30.64/0.9163). For subjective evaluation of 80 clinical patient images, image quality in all types of cerebrovascular diseases was also improved based on a deep-learning approach (p < 0.001).

CONCLUSIONS

Deep learning-based focal spot deblur algorithm can efficiently improve DSA image quality for better visualization of blood vessels and lesions in the image.

Low-Dose Volumetric Modulated Arc Therapy for a Patient With Head and Neck Involvement of Mycosis Fungoides: A Case Report With a Review of Literature

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma that slowly progresses over a period of years to decades. In some cases, lesions that spread to the scalp, neck, or facial skin can have a significant impact on cosmetic appearance and a patient's quality of life. Among the various treatments, radiation therapy is one of the most effective treatment modalities for patients with symptomatic cutaneous lesions. We report on an MF patient who had gradually increasing patches and plaques on the scalp, face, and neck and who underwent irradiation with 20 Gy administered in 10 fractions using volumetric modulated arc therapy. After undergoing this highly conformal technique, the patient obtained prolonged local control and significant alleviation of symptoms with acceptable adverse events. This technique constitutes a promising approach for treating a complex target due to its ability to provide homogeneous coverage of irregularly shaped target volumes along with its ability to preserve organs at risk. In addition, we systematically reviewed clinical reports on the management of extensive cutaneous lesions in MF patients undergoing other irradiation techniques.

Influencing Factors of Total Skin Irradiation With Helical Tomotherapy

Purpose

To investigate the influencing factors of total skin irradiation (TSI) with helical tomotherapy for guiding the clinical selection of the suitable parameters and optimizing the plan quality and efficiency.

Materials and Methods

Six patients with mycosis fungoides (MF) who received TSI were retrospectively selected. They were all dressed with 5 mm thick diving suits during the CT scan and treatment as a bolus to increase the superficial dose through buildup. The dose prescription was 24 Gy in 20 fractions and 5 times per week. During the planned pretreatment, Ring0, Ring1, Ring2, Ring3, and Ring4 of 1 cm thick away from the planning target volume (PTV) at the distances of 0, 1, 2, 3, and 4 cm and other normal tissues (NTs) were generated, respectively. The auxiliary structures were completely blocked during planning; while the field widths were 5 and 2.5 cm, the pitches were 0.287 and 0.215, the modulation factors were 4 and 3, and the other parameters remained consistent. Finally, the dose parameters of PTV and auxiliary structures, as well as the beam on time (BOT) and gantry period, were compared and analyzed.

Results

when the auxiliary structures were completely blocked with distance to PTV (d_PTV) above 3 cm were used, the mean dose (D_mean), conformity index (CI), and heterogeneity index (HI) of the PTV met the clinical requirements. As the d_PTV gradually increased, the BOT decreased while the volume of normal tissue that received excessive radiation increased correspondingly. If the d_PTV was less than 3 cm, the clinical requirements were not met. The field widths (FWs), pitches, and modulation factors (MFs) had no effect on PTV_mean and the HI. The FW of 2.5 cm was slightly better than 5 cm for the CI. The FW and MF had a significant impact on the BOT, which gradually increased with decreasing FW and increasing MF. Pitch had no effect on the BOT.

Conclusion

During planning with TSI patients, d_PTV is the key factor that has a significant influence on the plan quality. We found that the plan with the d_PTV above 3 cm can meet clinical objectives. The BOT increases as the d_PTV increases. The FWs also have an effect on the CI and BOT. Therefore, it is necessary to comprehensively balance these factors to optimize the quality and efficiency of the plan. We also found that different MFs and pitches have no obvious effect on the results.

Current treatment strategies and emerging therapies for cutaneous lymphoma

Cutaneous lymphoma is generally treated with skin-directed therapies (SDT) during the early and localized stages. For the refractory or advanced stages, systemic therapies are used. Previously, retinoids and interferons were used for SDT-resistant cases. Only a few chemotherapy options were available for more advanced disease. In recent years, many novel agents have been introduced and the strategy for systemic therapy has changed, especially for cutaneous T-cell lymphoma (CTCL). For SDT, helical tomotherapy, a new radiation modality, has been drawing attention as an option for radiotherapy. Targeted therapies such as histone deacetylase inhibitors, mogamulizumab, brentuximab vedotin, and denileukin diftitox are new treatment options. Chemotherapy agents such as gemcitabine and pralatrexate have been introduced; they are expected to have meaningful efficacy as monotherapy. Allogeneic hematopoietic stem cell transplantation is still considered for young patients with advanced CTCL as the only potentially curative treatment.

Successful treatment of tumor stage mycosis fungoides with total skin helical tomotherapy

Total skin electron beam therapy (TSEBT) is a treatment option for mycosis fungoides (MF). In Japan, it has been rarely performed because of the time required for each treatment, physical burden on patients, and difficulties in providing uniform dosimetry. In recent years, helical tomotherapy, an intensity-modulated radiation therapy that applies helical computed tomography technology, has been used to treat cancer. Total skin helical tomotherapy (TSHT) has been suggested as a promising alternative to TSEBT for patients with MF, but there are few reports from Japan. We used TSHT to treat a 28-year-old Japanese woman with tumor stage MF. She achieved complete remission with TSHT (12 Gy in six fractions over 6 days) and remained in remission for 32 months without additional treatment. Treatment-related grade 4 myelosuppression was observed, but resolved with blood transfusions and subcutaneous injection of granulocyte colony stimulating factor. Other adverse events were tolerable. Although careful attention should be paid to myelosuppression, TSHT might be a useful treatment option for MF.

Robust Treatment Planning in Intrafraction Motion Using TomoDirect™ Intensity-modulated Radiotherapy for Breast Cancer

BACKGROUND/AIM

To evaluate the robustness of radiotherapy treatment planning optimization for respiratory-moving breast cancer using fixed-angle beams planning TomoDirect™ intensity-modulated radiotherapy (IMRT).

MATERIALS AND METHODS

A minimax optimisation algorithm was applied to 10 breast cancer patients. Two sets of treatment plans with or without robust techniques were prepared considering anterior-posterior and head-tail movements due to respiration. Parameters were compared between treatment plans: 95% planned target volume (PTV) dose, conformal index and homogeneity index (HI), and organs at risk (OAR) parameters including the lung volume receiving 20 Gy or more (V20) and 5 Gy (V5).

RESULTS

Robust planning significantly improved parameters of 95% PTV dose and HI, without deteriorating V20 or V5 in the anterior-posterior movement, while it slightly improved 95% PTV and slightly deteriorated V20 in the head-tail movement.

CONCLUSION

Robust treatment planning improves coverage of targets moving because of respiration in the treatment of breast cancer using TomoDirect; however, normal lung doses should be cautiously evaluated on a case-by-case basis.

Dosimetric comparison of volumetric modulated arc therapy (VMAT) and high-dose-rate brachytherapy (HDR-BT) for superficial skin irradiation with significant curvature in one or more planes

PURPOSE

This study compares the plan quality of high-dose-rate brachytherapy (HDR-BT) and volumetric modulated arc therapy (VMAT) for superficial irradiation of large areas of skin with significant curvature in one or more planes.

METHODS

A total of 14 patients from two centres previously treated with either HDR-BT or VMAT were retrospectively replanned using the alternative technique. Sites included scalp and lower limbs. Identical computed tomography (CT) scans, clinical target volume (CTV) and organs at risk (OARs) and prescription were used for both techniques. Conformity, skin surface dose and OAR doses were compared.

RESULTS

Conformity index was consistently better with VMAT than HDR-BT (p < 0.01). Maximum skin surface dose (D0.1cc) had a higher mean of 49.6 Gy with HDR-BT compared to 31.4 Gy for VMAT (p < 0.01). Significantly smaller volumes of healthy tissue were irradiated with VMAT than with HDR-BT. This can be seen in brain volumes receiving 10, 20 and 30 Gy EQD2 and in extremities receiving 5 and 10 Gy. When close to the volume, the lens received significantly lower doses with VMAT (p < 0.01).

CONCLUSION

In this small sample, VMAT gives equal coverage with lower OAR and skin surface doses than HDR-BT for both scalp and extremities. VMAT is a useful technique for treating large, superficial volumes with significant curvature in one or more planes.

Helical Skin Radiation Therapy Including Total Skin Radiation Therapy Using Tomotherapy for Primary Cutaneous Lymphoma With Bone Marrow Suppression as a Related Adverse Event

PURPOSE

Total skin electron beam therapy (TSEBT) is useful for primary cutaneous lymphoma. However, helical skin radiation therapy (HSRT) using tomotherapy may avoid the complexity and uncertainty of TSEBT.

METHODS AND MATERIALS

All patients with primary cutaneous lymphoma who underwent HSRT at our hospital between June 2015 and July 2019 were investigated, including 7 patients registered in a clinical trial approved by an institutional review board (ID UMIN000022142). HSRT was performed in 3 partitioned skin areas: head and neck, trunk and arms, and legs.

RESULTS

A total of 24 patients with 53 skin areas (including 8 patients with 24 skin areas who had undergone sequential total skin irradiation), with a median follow-up time of 13 months (range, 2-50), were investigated. Twenty patients (83.3%) had mycosis fungoides (MF). For 41 of 53 (77.4%) cases, a dose of 20 Gy in 10 fractions was used. The overall response rate in the treated fields of each HSRT in patients with MF was 100%, including 38 (80.9%) complete response, 4 (8.5%) good partial response, and 5 (10.6%) partial response. Eight patients with MF who underwent sequential total skin irradiation showed a 100% complete response. For patients with MF, the median survival time after a first round of HSRT was 22 months (95% confidence interval [CI], 13.6-30.4 months), the median response duration of each HSRT was 5 months (95% CI, 3.67-6.32 months), and the median time to in-field reirradiation for each HSRT was 15 months (95% CI, 9.76-20.24 months). Bone marrow suppression (grade ≥3) often occurred (94.1%) with HSRT on trunk and arm skin. An early patient died of HSRT-caused grade 5 leukopenia.

CONCLUSIONS

HSRT targeting trunk and arm skin induced severe bone marrow suppression that led to a temporary palliative effect. TSEBT should still be considered standard treatment for primary cutaneous lymphoma covering the total body surface area.

Intensity-modulated radiation therapy for multiple targets with tomotherapy using multiple sets of static ports from different angles

BACKGROUND

To treat multiple targets separated in the craniocaudal direction within a short time, we invented a new technique using multiple static-port tomotherapy with the dynamic-jaw mode and named it the pseudo-DJDC (pDJDC) technique. We compared the pDJDC plans and helical tomotherapy plans using the dynamic-jaw mode (HDJ) for multiple targets. In the pDJDC plans, we used a beam set with 2-7 ports to the targets at the same level in the craniocaudal direction, and employed another beam set for other targets using different port angles (9-12 angles in total).

METHODS

In seven patients, two plans using the pDJDC and HDJ techniques were compared. For multiple targets (n = 2-6), 20-60 Gy in 2- to 7.5-Gy fractions were prescribed for the planning target volumes at D50%. The conformity index, uniformity index (D5%/D95%), dose distribution in the lung, and treatment time were evaluated.

RESULTS

The median conformity index of all seven patients was 3.0 for the pDJDC plans and 2.4 for the HDJ plans (P = 0.031). The median uniformity indices of the planning target volume (n = 25) for the two plans were 1.048 and 1.057, respectively (P = 0.10). For five patients with thoracic targets, the median mean lung doses were 2.6 Gy and 2.4 Gy, respectively (P = 0.63). The median V5Gy and V20Gy of the lungs in the five patients were 11.8% and 8.5% (P = 0.63), and 1.6% and 2.1% (P = 0.31), respectively. The pDJDC plans reduced the treatment time by 48% compared to the HDJ plans (median: 462 and 884 sec, respectively, P = 0.031).

CONCLUSION

The pDJDC technique allows treatment of multiple targets in almost half the time of the HDJ technique. The pDJDC plans were comparable to the HDJ plans in dose distribution, although the conformity index deteriorated.